The Status of Biological Invasions and their Management in South Africa in 2017

2017
THE STATUS OF BIOLOGICAL
INVASIONS AND THEIR MANAGEMENT
IN SOUTH AFRICA
SANBI Na ional S a us Repo Co e .indd 1-3 2018/03/28 3:55 PM
2017
THE STATUS OF BIOLOGICAL
INVASIONS AND THEIR MANAGEMENT
IN SOUTH AFRICA
SANBI Na ional S a us Repo Co e .indd 1-3 2018/03/28 3:55 PM
2017
THE STATUS OF BIOLOGICAL
INVASIONS AND THEIR MANAGEMENT
IN SOUTH AFRICA
SANBI Na ional S a us Repo Co e .indd 1-3 2018/03/28 3:55 PM
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
2017
THE STATUS OF BIOLOGICAL
INVASIONS AND THEIR MANAGEMENT
IN SOUTH AFRICA
PRETORIA
The sTaTus o biological in asions and Thei managemenT in souTh a ica in 2017
Lead edi o s:
b ian W. an Wilgen1 & John . Wilson1,2
Chap e lead au ho s:
Ka elyn T. aulkne 2,3, Zanele mnika hi2, Tumelo mo api2, Tendamudzimu munyai2, seba aolo ahlao2, b ian W. an
Wilgen1, John . Wilson1,2 & Tsungai Zengeya2,3
Wi h con ibu ions om
uqaya adams2, lee-anne bo ha2, oupa chauke4, Jenni e ill1, The ese o sy h5, llewellyn oxc o 1,6, michelle
g e e8, cha les g i i hs7, dai he be 9, Pa holmes1,10, Philip i ey2, s iaan Ko zé4, da id le mai e11, ob li le12,
Ka abo malakalaka4, John measey1, siyasanga miza2, be na d ndou4, Kha hu shelo nelukalo4, da id icha dson1,
Tama a obinson1, ian ushwo h13, oss shackle on1, hea he Te apon2, and ew Tu ne 5, uan eld man2,14,
gio anni ime ca i1 & cos as Zacha iades15
1dsT-n cen e o excellence o in asion biology, depa men o bo any and Zoology, s ellenbosch uni e si y
2sou h a ican na ional biodi e si y ins i u e (sanbi)
3dsT-n cen e o excellence o in asion biology, depa men o Zoology and en omology, uni e si y o P e o ia
4depa men o en i onmen al a ai s
5capena u e
6sou h a ican na ional Pa ks
7dsT-n cen e o excellence o in asion biology, depa men o Zoology, uni e si y o cape Town
8depa men o Plan and soil sciences, uni e si y o P e o ia
9KwaZulu-na al museum
10ci y o cape Town
11council o scien i ic and indus ial esea ch
12dsT-n cen e o excellence o bi ds as Keys o biodi e si y conse a ion, uni e si y o cape Town
13ezem elo KwaZulu-na al Wildli e
14depa men o conse a ion ecology and en omology, s ellenbosch uni e si y
15Plan P o ec ion esea ch ins i u e, ag icul u al esea ch council
Co e pho og aphs:
Top le – A gemone mexicana, yellow- lowe ed mexican poppy (pho og aph s. Tu ne )
Top middle – Mus musculus, house mouse (pho og aph c. g i i hs)
Top igh – Sagina p ocumbens, bi d-eye pea lwo (pho og aph m. g e e)
bo om le – Vespula ge manica, ge man wasp (pho og aph s. an noo d )
bo om middle – Pinus species, pine ees (pho og aph b. an Wilgen)
bo om igh – S u nus ulga is, common s a ling (pho og aph c. g i i hs)
Technical edi ing: sanbi g aphics & edi ing
design & layou : ink design
co e design: ink design
Ci ing his publica ion
o ci a ions in he scien i ic li e a u e: an Wilgen, b.W. & Wilson, J. . (eds.) 2018. The s a us o biological in asions
and hei managemen in Sou h A ica in 2017. sou h a ican na ional biodi e si y ins i u e, Ki s enbosch and
dsT-n cen e o excellence o in asion biology, s ellenbosch.
Fo ci a ions in policy documen s: SANBI and C•I•B, 2018. The s a us o biological in asions and hei managemen in
Sou h A ica in 2017. sou h a ican na ional biodi e si y ins i u e, Ki s enbosch and dsT-n cen e o excellence
o in asion biology, s ellenbosch.
ISBN: 978-1-928224-18-1
P in ed by: no us P in solu ions, 26 eedom Way, milne on, cape Town 7441 sou h a ica.
e-mail: in o[email p o ec ed]. www.no us.holdings
copy igh © 2018 sou h a ican na ional biodi e si y ins i u e (sanbi). all igh s ese ed. ep oduc ion o his publica ion o
educa ional o o he non-comme cial pu poses is au ho ised wi hou p io w i en pe mission om he copy igh holde p o ided
he sou ce is ully acknowledged. ep oduc ion o his publica ion o esale o o he comme cial pu poses is p ohibi ed
wi hou p io w i en pe mission o he copy igh holde .
iii
Fu c aea oe ida (Mau i ian hemp) – SANBI
INDEPENDENCE OF THE
STATUS REPORT
This s a us epo cons i u es an independen assessmen o he
s a us o biological in asions and hei managemen in Sou h A ica.
I is he i s such coun y-le el assessmen speci i cally on biological
in asions anywhe e in he wo ld. The epo is in ended o in o m he
de elopmen and ongoing adap a ion o app op ia e policies and
con ol measu es, bo h o educe he nega i e impac s o in asi e
species on ecosys ems, he economy, and people, and o e ain any
bene i s o in asi e species whe e possible and desi able.
The compila ion o he epo was o e seen by a eam o edi o s and
con ibu ing au ho s employed by he Sou h A ican Na ional
Biodi e si y Ins i u e (SANBI) and he DST-NRF Cen e o Excellence
o In asion Biology a (C•I•B). Inpu s (including da a, pee - e iewed
pape s, and unpublished epo s) we e also ob ained om esea che s
and manage s om di e se ins i u ions ac oss Sou h A ica. Funding
o he compila ion o he epo was ob ained h ough he na ional
Depa men o En i onmen al A ai s (DEA) as pa o SANBI’s Medium
Te m Expendi u e F amewo k. In o de o add ess any po en ial
con l ic s o in e es , and o ensu e independence o he epo , he
ollowing s eps we e aken:
• D a s o he s a us epo we e widely ci cula ed o con ibu ing
au ho s and o he s akeholde s, who we e in i ed o submi
commen s, conce ns o addi ional in o ma ion, wi h wo
dedica ed ounds o e iew in 2017;
• Commen s and conce ns aised we e cap u ed in a da abase,
along wi h he d a ing eam’s esponses o hese commen s
and conce ns. This da abase is a ailable on eques ;
• A Re iew and Ad iso y Commi ee was appoin ed, chai ed by an
expe on assessmen s, om he Uni e si y o he Wi wa e s and,
Sou h A ica. This commi ee app o ed he e iew p ocess and
ook esponsibili y o ensu ing edi o ial independence; and
• An independen Re iew Edi o will be appoin ed o assess he
e iew p ocess on comple ion o he i s s a us epo , wi h a
iew o s eng hening he p ocess i necessa y o u u e epo s.
i
EDITORIAL CONVENTIONS
Species
Bo h scien i i c and common names a e p o ided when e e ing o species. Au ho i ies o scien i i c names a e
p o ided in Appendix 3, and a e no used in he main ex o in ables. Each species is assigned only one common
name. The common name used is in English, ecognising ha mo e han one English common name may exis ,
and ha common names in o he Sou h A ican o i cial languages also exis . Excep ions a e made when a non-
English common name is p edominan ly o exclusi ely used o desc ibe a species (e.g. in he case o Acacia
cyclops, he common name “ ooik ans” is used in p e e ence o he English “ ed eye”).
Ac onyms
All ac onyms a e de i ned a i s use in e e y chap e , and a e also de i ned in able headings and in he legends
o i gu es. A ull lis o ac onyms and hei de i ni ions is p o ided a he beginning o he epo .
Te minology
To assis he eade who may no be amilia wi h commonly-used e ms in in asion biology, a glossa y o e ms
is p o ided a he beginning o he epo .
Cu ency
Sou h A ican ands a e deno ed as ZAR, and no R.
Re e ences
All e e ences o he ex and o appendices a e p o ided in a single lis a he end o he epo . In he
bibliog aphy, e e ences wi h mo e han en au ho s only ha e he i s ou au ho s lis ed, ollowed by “e al.”
Indica o s
All indica o s a e numbe ed whe e e hey a e men ioned in he ex o in ables. The numbe ing o indica o s
ollows he numbe s se ou in Chap e 2.

TABLE OF CONTENTS
INDEPENDENCE OF THE STATUS REPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III
EDITORIAL CONVENTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV
PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .X
LIST OF ACRONYMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .XII
GLOSSARY OF TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XIII
EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XVI
1. INTRODUCTION
Chap e summa y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1. The impo ance o biological in asions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. Pu pose o he s a us epo on biological in asions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3. Legisla i e backg ound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4. Aspec s o biological in asions ha a e no co e ed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5. S uc u e o he s a us epo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.6. P ocess ollowed o p oduce his s a us epo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2. INDICATORS
Chap e summa y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.1. In oduc ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.2. The a ionale o he app oach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3. Con i dence le els . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.4. Indica o s used in his epo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.4.1. Pa hways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.4.2. Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.4.3. A eas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.4.4. In e en ions (e ec i eness o con ol measu es and egula ions) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.5. High-le el Indica o s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.6. F amewo k . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3. PATHWAYS OF INTRODUCTION
Chap e summa y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.1. In oduc ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.2. Da a Sou ces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.3. S a us o he pa hways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.3.1. S a us o he pa hways o in oduc ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.3.2. S a us o he pa hways o dispe sal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.3.3. Fu u e changes o he pa hways o in oduc ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.4. Unce ain ies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.5. Syn hesis and indica o alues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4. THE STATUS OF ALIEN SPECIES
Chap e summa y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.1. In oduc ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.2. The numbe and s a us o alien species in Sou h A ica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.2.1. Numbe o alien species in Sou h A ica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.2.2. S a us o alien species in Sou h A ica. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.3. The Ex en o alien species in Sou h A ica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.3.1. Numbe o b oad-scale egions occupied pe species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.3.2. Numbe o qua e deg ee g id cells occupied pe species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.4. Abundance o alien species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.5. The impac o alien species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
4.6. Syn hesis and indica o alues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
5. THE STATUS OF INVADED AREAS
Chap e summa y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
5.1. In oduc ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.2. Alien species ichness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.2.1. In asi e species ichness pe la ge-scale na ional sub-di ision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.2.2. In asi e species ichness pe i ne -scale na ional sub-di ision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.2.3. Alien species ichness a di e en s ages o he Uni i ed F amewo k o Biological In asions . . . . . . . . . . . . . . . . . . 77
5.3. Rela i e alien species ichness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.4. Rela i e in asi e abundance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.5. Impac o in asions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
5.5.1. Impac s on su ace wa e uno and g oundwa e by p ima y ca chmen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
5.5.2. Impac s on angeland p oduc i i y by biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.5.3. Impac s on biodi e si y in ac ness by biome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.5.4. Impac s on i e egimes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.5.5. Impac s on ma ine habi a s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.6. Syn hesis and indica o alues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
6. THE EFFECTIVENESS OF CONTROL MEASURES
Chap e summa y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.1. In oduc ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.2. Pa hway- ela ed con ol measu es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
6.3. Species-speci i c con ol measu es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
6.3.1. The s a us o a emp s a e adica ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
6.3.2. Biological con ol o in asi e plan s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100
6.3.3. In asi e species managemen p og ammes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103
6.3.4. Managemen o in asi e plan s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
6.3.5. Managemen o in asi e eshwa e i sh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
6.3.6. Managemen o in asi e mammals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106
6.3.7. Managemen o in asi e he pe o auna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
6.3.8. Managemen o in asi e in e eb a es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
6.4. A ea-speci i c con ol measu es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108
6.4.1. Assessmen o e ec i eness a a na ional scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108
6.4.2. Assessmen s o con ol e ec i eness a i ne scales whe e in o ma ion is a ailable . . . . . . . . . . . . . . . . . . . . . . .109
6.4.3. Re u ns on in es men om con ol measu es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114
6.4.4. Nega i e impac s o con ol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
6.5. Syn hesis and indica o alues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
6.5.1 O e all e ec i eness o con ol measu es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
6.5.2. Alloca ion o alues o indica o s o pa hway managemen e ec i eness . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
6.5.3. Alloca ion o alues o indica o s o species managemen e ec i eness . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
6.5.4. Alloca ion o alues o indica o s o a ea managemen e ec i eness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
6.5.5. Es ima ion o high-le el indica o s o o e all managemen e ec i eness . . . . . . . . . . . . . . . . . . . . . . . . . . 126
7. EFFECTIVENESS OF REGULATIONS
Chap e summa y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
7.1. In oduc ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132
7.2. The s a e o he cu en egula o y amewo k . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
7.2.1. Wha is equi ed o imp o e he e ec i eness o he egula ions? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
7.3. E ec i eness o egula ions ele an o managing alien species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137
7.3.1. Pe mi s issued o he impo o new species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
7.3.2. Pe mi s issued o lis ed in asi e species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
7.3.3. In asi e species managemen p og ammes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142
7.3.4. Eme gency in e en ions and en o cemen ac ions in ol ing lis ed in asi e species . . . . . . . . . . . . . . . . . . . . . . 142
7.3.5. Risk assessmen s o lis ed species, o candida es o lis ing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
7.4. Regula ions ele an o managing speci i c a eas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147
7.4.1. No i i ca ions om landowne s ega ding alien species on hei land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147
7.4.2. No i i ca ions and di ec i es issued o landowne s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147
7.4.3. Le el o compliance wi h p ope y ans e no i i ca ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153
7.4.4. In asi e Species Moni o ing, Con ol and E adica ion Plans (i.e. a ea managemen plans) . . . . . . . . . . . . . . . . . .154
7.4.5. S a us epo s o p o ec ed a eas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
7.5. Resea ch p oposal and epo s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
7.6. P osecu ions unde he egula ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
7.7. Syn hesis and indica o alues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157
8. KNOWLEDGE AND INFORMATION GAPS IN UNDERSTANDING
THE STATUS OF BIOLOGICAL INVASIONS
Chap e summa y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159
8.1. App oach used in his chap e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160
x
• Lis ed alien species: all alien species ha a e egula ed unde he Na ional En i onmen al Managemen :
Biodi e si y Ac , 2004 (Ac no. 10 o 2004), Alien and In asi e Species (A&IS) Regula ions, 2016.
• Na i e species: see Indigenous species.
• Na u alised (syn. es ablished): Alien species ha sus ain sel - eplacing popula ions o se e al li e cycles o
o e a gi en pe iod o ime wi hou di ec in e en ion by people, o despi e human in e en ion.
• Ne p esen alue: he p esen -day alue o money when compa ed o i s pas alue a e ac o ing in in l a ion.
• Pa hways: a b oadly de i ned e m ha e e s o he combina ion o p ocesses and oppo uni ies ha esul in
he mo emen o alien species om one place o ano he .
• Pe mi : an o i cial documen issued in e ms o Chap e 7 o Na ional En i onmen al Managemen : Biodi e si y
Ac , 2004 (Ac no. 10 o 2004).
• Pes (c . en i onmen al pes and weed): an o ganism ha causes nega i e impac s. The a ec ed sec o migh
be speci i ed, so an ag icul u al pes will impac nega i ely on ag icul u al p oduc ion. Pes s can be alien o
indigenous, and a e usually aken o e e o animals, wi h pes plan s mo e speci i cally e e ed o as weeds
and pes ungi o mic obes e e ed o as diseases.
• P e-in oduc ion: a s age in he in asion p ocess whe e a species is no cu en ly p esen in a egion o in e es .
• P ohibi ed species: species ha a e no na i e o Sou h A ica lis ed as p ohibi ed unde he Na ional
En i onmen al Managemen : Biodi e si y Ac , 2004 (Ac no. 10 o 2004) Alien and In asi e Species (A&IS)
Regula ions, 2016. These species a e assumed o be absen om he coun y and new in oduc ions a e p ohibi ed.
• P opagule p essu e: a concep ha encompasses a ia ion in he quan i y, quali y, composi ion and a e
o supply o seeds, indi iduals, o o he ep oduc i ely iable ma e ial o an alien species esul ing om he
anspo condi ions and pa hways be ween sou ce and ecipien egions.
• Po o en y: an o i cial poin o en y o depa u e om Sou h A ica h ough which goods and people may
en e o lea e a coun y, o example a bo de pos , ai po o ha bou .
• Regula ion: a law, ule o o he o de p esc ibed by au ho i y, especially o egula e conduc .
• Risk analysis: he assessmen o he na u e, likelihood and consequences o a gi en alien axon causing
nega i e impac s (i.e. isk assessmen ), and he iden i i ca ion o measu es ha can be implemen ed o
educe o manage such isk, aking in o accoun socio-economic conside a ions.
• Risk assessmen : pa o isk analysis, assessing he na u e, likelihood and consequences o a gi en alien
axon causing nega i e impac s.
• Sp ead: see Expansion.
• S a us: he s a e, condi ion o s age o a ai s a a pa icula ime.
• Taxon (pl. axa): a g oup o o ganisms ha all sha e pa icula p ope ies (usually e olu iona y his o y). The
g ouping can be below, a , o abo e he species le el.
• Uni i ed F amewo k: a amewo k he de i nes biological in asions in e ms o he in oduc ion-
na u alisa ion-in asion con inuum and p o ides a me hod o ca ego ising alien species in e ms o
hei in oduc ion s a us (see Appendix 3 o de ails).
• Vec o s: a b oadly de i ned phenomenon in ol ing dispe sal mechanisms ha can be bo h non-human and
human media ed. I is o en used o e e o he ac ual mechanism by which alien species a e able o a i e
a new a eas.
• Weed (c . pes , en i onmen al weed): a plan ha causes nega i e impac s. Weeds can ei he be alien o na i e.

x i
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
EXECUTIVE SUMMARY1
Biological in asions a e a la ge and g owing en i onmen al p oblem, globally and in Sou h A ica. Many
housands o species ha e been ansloca ed om hei indigenous anges o no el en i onmen s, whe e some
become in asi e and sp ead ac oss na u al ecosys ems, h ea ening indigenous biodi e si y and educing he
abili y o ecosys ems o deli e i al se ices. These biological in asions o en ha e di ec nega i e impac s on
he wellbeing o many people, and in pa icula h ea en u al li elihoods.
This epo cons i u es he i s comp ehensi e a emp o assess he s a us o biological in asions ac oss all
aspec s o he p oblem a a na ional le el. The epo is based on in o ma ion om a ange o sou ces, including
inpu s om expe s and p ac i ione s, a las da a, published scien i i c pape s and heses, and managemen
eco ds om go e nmen agencies. D a e sions o he epo we e sen ou o a wide and ep esen a i e ange
o in e es ed pa ies in wo ounds o e iew, which esul ed in he inclusion o addi ional in o ma ion.
This epo does no co e he social bene i s associa ed wi h alien species con ol p og ammes ha a e
implemen ed wi h he addi ional goals o employmen c ea ion and po e y elie , as his is no equi ed in
e ms o he egula ions, as well as because he e ha e been no a emp s o da e o quan i y hese bene i s.
Howe e , hese bene i s should ideally be conside ed when e u ns on in es men om con ol p ojec s a e
calcula ed.
The epo is s uc u ed a ound ou aspec s: pa hways o in oduc ion and dispe sal; he numbe , dis ibu ion
and impac o indi idual species; species ichness and abundance o alien species in de i ned a eas, and hei
impac s on hose a eas; and he e ec i eness o in e en ions, i.e. Ha e Sou h A ican egula ions and con ol
e o s been e ec i e in educing he p oblem? A o al o 21 indica o s we e de eloped o assess he s a us o
hese aspec s. In addi ion, ou high-le el indica o s (one o each aspec ) we e de eloped o use in he na ional
sui e o en i onmen al indica o s on which he Depa men o En i onmen al A ai s epo s on a egula basis.
Mos alien species ound in Sou h A ica oday we e in en ionally in oduced many yea s ago, ei he delibe a ely
wi h he goal o es ablishing popula ions in na u e, o o ho icul u e, ag icul u e, o es y o he pe ade ( om
whe e some escaped o become in asi e). The emainde we e in oduced acciden ally as commodi y
con aminan s o as s owaways on anspo ec o s. While he a e o in en ional in oduc ion o high- isk species
is expec ed o decline due o imp o ed egula ion, i is also expec ed ha he a e o unin en ional in oduc ions
will inc ease due o inc eases in ade and ou ism. The a e a which species a e a i ing in he coun y appea s
o be g adually inc easing.. Once an alien species is in oduced o Sou h A ica, u he sp ead wi hin he coun y
1 This execu i e summa y p o ides a b ie , high-le el o e iew o he con en s o his epo . Mo e de ailed summa ies appea a he s a o each
chap e . Chap e 9 also p o ides a se o key policy- ele an messages.
x ii
PREFACE
is highly likely and e y di i cul o s op. The e is a h i ing ade in alien species o a a ie y o pu poses wi hin
Sou h A ica’s bo de s. Alien species can also be acciden ally anspo ed along he coun y’s ex ensi e anspo
ne wo ks, and in asi e species can sp ead na u ally.
A o al o 556 in asi e axa ha e been lis ed unde he Na ional En i onmen al Managemen : Biodi e si y Ac ’s
Alien and In asi e Species Regula ions. The ac ual numbe o in asi e species is highe , wi h 775 ha ing been
iden i i ed o da e. Mos o hese in asi e species a e e es ial and eshwa e plan s (574 species) o e es ial
in e eb a es (107 species).
A o al o 107 species we e conside ed by expe s o be ha ing ei he majo o se e e impac s on biodi e si y
and/o human wellbeing; he as majo i y o hese (75%) we e e es ial o eshwa e plan s.
Alien species ichness was highes in he Sa anna, G assland, Indian Ocean Coas al Bel and Fynbos biomes, wi h
ela i ely low species ichness in he mo e a id Ka oo and Dese biomes. Alien ees and sh ubs can domina e
a eas such as ynbos ca chmen s and coas al a eas; mesqui e ees (P osopis spp.) domina e a id a eas; many
ipa ian zones a e in aded by ees; many angelands a e in aded by cac i and he baceous annual and pe ennial
plan s; and ew indigenous i sh species su i e in s eams in aded by alien i sh.
The e a e e y ew s udies ha co e he combined impac s o in asi e species on pa icula a eas. A ailable
s udies es ima e he combined impac s o in asi e plan s on su ace wa e uno a be ween 1450 o 2450
million m3 pe yea . I no emedial ac ion is aken, educ ions in wa e esou ces could ise o be ween 2600 and
3150 million m3 pe yea , se e ely impac ing d ough -s icken ci ies like Cape Town. Reduc ions in he p oduc i i y
o angelands, and in biodi e si y in ac ness, a e low a p esen (be ween 1 and 3%), bu hese impac s a e
expec ed o g ow apidly as in asi e plan s en e a s age o exponen ial g ow h. Biological in asions accoun o
25% o he educ ion in Sou h A ican biodi e si y seen o da e.
In e ms o con ol measu e inpu s, Sou h A ica’s Alien and In asi e Species Regula ions a e subs an ial, as hey
co e mos aspec s o he p oblem. La ge sums o money ha e been spen (cu en ly ZAR1.5 billion pe yea ),
especially on he con ol o e es ial and eshwa e plan species. This is almos ce ainly an unde es ima e as
i only includes unding om he Depa men o En i onmen al A ai s, and no om o he go e nmen o semi-
go e nmen en i ies, o he p i a e sec o . Planning co e age is low, and he e is li le e idence o adequa e
le els o goal-se ing o moni o ing.
x iii
Con ol measu e ou pu s a e assessed in e ms o he p opo ion o pa hways, species o a eas ha ha e been
subjec ed o con ol. The Con en ion on Biological Di e si y ecognises 44 pa hways o in oduc ion, and 34 o
hese pa hways (77.3%) a e managed o some ex en . Al hough 556 axa a e lis ed in he Alien and In asi e
Species egula ions, no all o hese a e subjec ed o ac i e managemen . Fo example, ~126 ou o 379 alien
e es ial and eshwa e plan axa ha e been a ge ed o some con ol, and o hese, eigh species make up
80% o he a ea subjec ed o ea men . In e ms o a eas, less han 1% o in aded land has been epo ed o ha e
been he subjec o con ol measu es.
Da a on he ou comes o con ol measu es a e so ely lacking. The impac o pa hway egula ion on a es o
in oduc ion o in asi e species canno ye be de e mined, gi en ha hey ha e only been in place o a sho
ime. Con ol measu es ha e been shown o be e ec i e in some localized a eas bu no so in o he s. While he
si ua ion would a guably ha e been wo se had he e been no con ol, cu en con ol e o s ha e no been
e ec i e in p e en ing he ongoing sp ead o in asi e species when iewed a a na ional scale.
The le el o con i dence in almos all hese es ima es is low. This can be imp o ed in u u e s a us epo s as mo e
da a a e colla ed and cu a ed, bu in many cases new p ocesses a e equi ed o moni o and epo on biological
in asions i policy and managemen decisions a e o be e idence-based. In pa icula h ee key a eas o ocus a e
iden i i ed: (1) he need o mo e esea ch o de e mine and assess he impac s o alien species; (2) be e
moni o ing o he e ec i eness o cu en con ol measu es; and (3) he de elopmen o me hods o look a he
impac o biological in asions and hei managemen on socie y as a whole.
The epo concludes by p o iding a lis o policy- ele an messages ha ha e been dis illed om he
assessmen , and hese should be conside ed when o mula ing en i onmen al policies o he coun y as a
whole. Besides expanding on he poin s desc ibed abo e, i is no ed ha i should be impe a i e o imp o e
managemen e i ciency, gi en he subs an ial economic and social consequences ha would be associa ed
wi h a ailu e o adequa ely add ess he p oblem o biological in asions. This will equi e di i cul choices and
ade-o s o be made, including he need o p ac ice conse a ion iage by ocussing e o on p io i y
pa hways, species, and a eas.
Ac ido he es is is (common myna) – Richa d Taylo
1
INTRODUCTION
Lead au ho s:
B ian an Wilgen, John Wilson
Con ibu ing au ho s:
Seba aolo Rahlao,
Tsungai Zengeya
Chap e summa y
Biological in asions can ha e p o ound nega i e impac s on biodi e si y,
educe he abili y o ecosys ems o deli e he se ices needed o main ain and
imp o e he li elihoods o he people o Sou h A ica, and impac di ec ly upon
people’s wellbeing.
This epo p esen s he i s comp ehensi e na ional-scale assessmen o he
s a us o biological in asions in Sou h A ica, and he i s such coun y-le el
assessmen speci i cally on biological in asions anywhe e in he wo ld. The
epo is in ended o in o m he de elopmen and ongoing adap a ion o
app op ia e in e en ions o educe he nega i e impac s o biological in asions
on biodi e si y and ecosys ems, he economy, and people, while p ese ing
any bene i s.
S a us is add essed in e ms o i e aspec s: pa hways o in oduc ion and
sp ead; he es ablishmen , dis ibu ion, and impac o species; he le el o
which a eas a e in aded and he esul ing o e all impac s; he e ec i eness o
con ol measu es; and he e ec i eness o egula ions.
This epo also ul i ls he legal equi emen o he Sou h A ican Na ional
Biodi e si y Ins i u e o submi a epo on he s a us o biological in asions,
and he e ec i eness o con ol measu es and egula ions, o he Minis e o
En i onmen al A ai s. This i s epo also p o ides a amewo k o u u e
epo s, wi h epo s due e e y h ee yea s.
This chap e b ie l y desc ibes he p ocess ollowed o p oduce he epo ,
which included he appoin men o a Re e ence and Ad iso y Commi ee o
p o ide guidance and ad ice, he ga he ing o in o ma ion om a wide ange
o sou ces, and e iew by s akeholde s and con ibu o s.
EFFECTIVENESS
OF RESPONSES
The cu en e ec i eness o managemen
in e en ions a ies. In some cases, good
p og ess has been made, bu in o he s he
in e en ions ha e been less e ec i e.
Undoub edly, we would be wo se o i
no ac ion had been aken, bu e ec i eness
can be inc eased subs an ially by be e
planning and moni o ing and he mo e
widesp ead use o accep ed bes -p ac ice
con ol measu es.
Ly h um hyssopi olia (hyssop looses i e) – Ch is ian Fische
2
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
1.1. THE IMPORTANCE OF BIOLOGICAL INVASIONS
Biological in asion is he phenomenon o he anspo a ion o o ganisms h ough in en ional o acciden al
human ac i i y o a eas ou side o hei na u al ange, and he a e o such o ganisms in hei new anges,
including hei abili y o su i e, es ablish, ep oduce, dispe se, sp ead, p oli e a e, and in l uence in aded
ecosys ems (Richa dson e al., 2011a). Biological in asions a e a g owing en i onmen al p oblem wo ldwide, and
Sou h A ica in pa icula is home o a la ge and g owing numbe o in asi e species.
Thousands o species ha e been in oduced o Sou h A ica o e he yea s. Many o hese alien species a e
bene i cial. Almos all ag icul u e and o es y p oduc ion is based on alien species, and alien species a e widely
used in ho icul u e, aquacul u e, and ma icul u e, o a e kep as pe s. Only a small p opo ion o alien species
become in asi e hough his a ies ma kedly be ween axa (~0.1–10%). This subse o alien species can educe
he abili y o ecosys ems o deli e se ices, nega i ely a ec ing he economy o in aded a eas, and ul ima ely
impac ing upon all Sou h A icans. In asi e ees and sh ubs educe wa e uno and g oundwa e echa ge,
educing he wa e supplies o al eady-s essed a ms, owns and ci ies; plan s ha in ade angelands educe he
capaci y o he land o suppo li es ock and h ea en he li elihoods o people ha depend on li es ock
p oduc ion; and in asi e plan s and animals impac nega i ely on biodi e si y and he se ices ha Sou h A ica’s
di e se na u al ecosys ems p o ide ( om eco ou ism o ha es ing ood, cu l owe s, and medicinal p oduc s).
In 1996, Sou h A ica adop ed a new Cons i u ion (Cons i u ion o he Republic o Sou h A ica Ac , Ac 108 o
1996). The Bill o Righ s (Chap e 2) is cen al o his Cons i u ion as i ensh ines he igh s o all people in he
coun y. Sec ion 24 o he Bill o Righ s gua an ees he igh o an en i onmen ha is no ha m ul o people’s
heal h o wellbeing, and p o ides o en i onmen al p o ec ion o he bene i o u u e gene a ions h ough
easonable legisla i e and o he measu es ha p e en “ecological deg ada ion, p omo e conse a ion, and
secu e ecologically sus ainable de elopmen ”. This impa s a esponsibili y bo h o con ol in asi e species so as
o educe hei nega i e impac s, and o y o p ese e any bene i s ha such in asi e species may p o ide.
C ucially his is no only a ma e o balancing ecological and economic impe a i es, as in some si ua ions
in asi e species a e economically use ul o some people bu economically damaging o o he people Van Wilgen
& Richa dson, 2014; Wood o d e al., 2016).
Sou h A ica has been ac i ely managing biological in asions o well o e a cen u y (e.g. Mo an, Ho mann &
Zimme mann, 2013). While his o ically he ocus was on limi ing di ec impac s o ag icul u al p oduc ion, he
ul ima e goal o hese measu es is o p e en he e osion o ecosys em se ices and o p o ec people om he
ongoing expansion o nega i e impac s. This is in line wi h he cons i u ional obliga ion.
1.2. PURPOSE OF THE STATUS REPORT ON BIOLOGICAL INVASIONS
This s a us epo is in ended o in o m he de elopmen and ongoing adap a ion o app op ia e policies and
con ol measu es, bo h o educe he nega i e impac s o in asi e species on ecosys ems, he economy, and
people, and o e ain any bene i s o in asi e species whe e possible and desi able. Such con ol measu es and
policies ideally need o be based on an unde s anding o he dynamics o biological in asions, he magni ude
and dis ibu ion o he impac s o biological in asions, an assessmen o he implica ions o hose impac s, and

3
CHAPTER 1
I
INTRODUCTION
on he p ospec s o con aining o educing hem. Once managemen goals
a e se and implemen ed, hei ou comes should be moni o ed and
e alua ed egula ly, wi h obse a ions eeding back o adjus p io i ies o
basic in en o y and ecological esea ch. Howe e , his p ocess is a ely as
s aigh o wa d as his (Figu e 1.1). This s a us epo syn hesizes cu en
unde s anding o he p oblem a ising om in en o ies and ecological
esea ch, as well as on he ou pu s o exe cises o moni o and e alua e he
ou comes o con ol measu es, in a o m ha is o alue o policy make s and
manage s. The cu en equi emen is o epea his cycle e e y h ee yea s
(see sec ion 1.3 below).
Basic in en o y
and ecological
esea ch
Assess
implica ions and
o mula e policy
Se goals and
implemen
managemen
measu es
Moni o ing and
e alua ion
A
Basic in en o y
and ecological
esea ch
Assess
implica ions and
o mula e policy
Se goals and
implemen
managemen
measu es
Moni o ing and
e alua ion
B
STATUS
REPORT
FIGURE 1.1 The Na ional S a us Repo is a o mal mechanism o inc ease he connec i i y be ween esea ch, policy and
implemen a ion. The op panel (A) shows an idealised p ocess whe eby esea ch is conduc ed ha is in e p e ed in e ms o
implica ions o managemen exp essed in app op ia e policy, which in u n is implemen ed. Implemen a ion is moni o ed and
e alua ed and adjus ed acco dingly, i.e. managemen is adap i e. How and wha is moni o ed and e alua ed is in o med by basic
in en o y and ecological esea ch and ice e sa. The bo om panel (B) shows he eal si ua ion. The e a e some imes di ec links
be ween basic esea ch and implemen a ion, and many mo e eedbacks, bu o en he links a e incomple e o b oken. Di e en
people and o ganisa ions a e in ol ed in esea ch, policy o mula ion, managemen , and e alua ions, and hei speci i c goals and
in e es s a e o en no closely aligned, no do hey always ha e he ime o in e ac . The e is a a ie y o mechanisms o inc ease
communica ion be ween di e en ole playe s. A na ional s a us epo is one o mal way o colla ing in o ma ion om basic
in en o ies and ecological esea ch and om moni o ing and e alua ion, and p o iding i in a o m ha can assis wi h he p ocesses
o assessing implica ions and o mula ing app op ia e policy, and se ing goals and implemen ing managemen measu es.
FACT
The Na ional S a us Repo
on Biological In asions in
Sou h A ica is he i s such
epo anywhe e in he
wo ld. I s pu pose is o se a
benchma k agains which
ends in his p oblem can
be acked o e ime.
4
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
1.3. L EGISLATIVE BACKGROUND
His o ically, Sou h A ica has esponded o he h ea posed by in asi e species
by ad hoc, o en piecemeal, legisla ion. Recen ly, he e has been a mo e
comp ehensi e sec o -speci i c app oach. In pa icula , egula ions unde he
Conse a ion o Ag icul u al Resou ces Ac (CARA) (Ac 43 o 1983), we e
p omulga ed o go e n he managemen o ce ain (lis ed) in asi e plan species
(“weeds”); while he Ag icul u al Pes s Ac , 1983 (Ac 36 o 1983) p o ides o
measu es o comba ag icul u al pes s and p e en hei in oduc ion. Despi e
he ini ial in en o he CARA (which was o con ol ag icul u al weeds), he
species lis ed included plan s whose impac s we e p ima ily el in un ans o med
na u al ecosys ems, i.e. en i onmen al weeds.
In 1998, he Na ional En i onmen Managemen Ac (NEMA) (Ac 107 o 1998)
was enac ed o p o ide a amewo k o en i onmen al managemen . In 2004, he
Na ional En i onmen al Managemen : Biodi e si y Ac (NEM:BA, Ac 10 o 2004)
was passed. NEM:BA is one o he laws buil a ound he NEMA amewo k, and is
in ended o p omo e he p o ec ion and conse a ion o Sou h A ica’s ich
biodi e si y. In 2014, a se o egula ions was p omulga ed in e ms o his Ac , by
which he managemen o biological in asions is o be go e ned. These egula ions
add ess he impo o new alien species, place exis ing alien species in o a numbe
o ca ego ies, and speci y how hese species a e o be con olled o managed. One
o he speci i c equi emen s con ained in hese egula ions is o he Sou h A ican
Na ional Biodi e si y Ins i u e (SANBI) o p oduce egula s a us epo s (Box 1.1).
Sec ion 2 o NEM:BA s a es ha Sou h A ica should “gi e e ec o a i i ed
in e na ional ag eemen s ela ing o biodi e si y which a e binding on he Republic”.
The mos impo an o hese ag eemen s is he Con en ion on Biological Di e si y
(CBD), which Sou h A ica a i i ed in No embe 1995. A icle 8(h) o his con en ion
equi es each Con ac ing Pa y, as a as possible and as app op ia e, o “p e en
he in oduc ion o , con ol o e adica e hose alien species which h ea en
ecosys ems, habi a s o species”. A icle 19 also equi es each con ac ing pa y o
ake legisla i e, adminis a i e o policy measu es o p o ide o e ec i e
pa icipa ion in he con en ion. O he ele an con en ions include he In e na ional
Plan P o ec ion Con en ion (IPPC), which equi es ha signa o y coun ies mee
equi emen s designed o educe he isks o pes s o plan s om ei he lea ing o
en e ing he coun y (while pes s o iginally e e ed o animals and ungi, he IPPC
de i ni ion has ecen ly been expanded o include plan s as pes s hemsel es). F om
a ma ine pe spec i e, he UN Con en ion on he Law o he Sea obliges pa ies o
p e en , educe and con ol he in en ional o acciden al in oduc ion o species o
he ma ine en i onmen whe e hey may ha e signi i can ha m ul e ec s. The
In e na ional Con en ion o he Con ol and Managemen o Ship’s Ballas Wa e
and Sedimen s imposes obliga ions o p e en , minimise, and ul ima ely elimina e
he ans e o ha m ul aqua ic o ganisms and pa hogens h ough he con ol and
managemen o ship’s ballas wa e and sedimen s.
EFFECTIVENESS
OF RESPONSES
Sou h A ica has
comp ehensi e na ional
egula ions o deal wi h
biological in asions. Many
p o isions a e inno a i e,
allowing o bene i s o be
de i ed om some in asi e
species while simul aneously
equi ing hei con ol whe e
i is equi ed. The egula ions
ha e only been in o ce o
h ee yea s, so i is oo ea ly
o be able o assess he
deg ee o which hey ha e
a ec ed he s a us o
biological in asions in
he coun y.
5
CHAPTER 1
I
INTRODUCTION
BOX 1.1 REGULATORY REQUIREMENT FOR A NATIONAL STATUS REPORT
In e ms o sec ion 11 o he Alien and In asi e Species Regula ions p omulga ed unde he Na ional
En i onmen al Biodi e si y Ac (NEM:BA) (Ac 10 o 2004), he Sou h A ican Na ional Biodi e si y Ins i u e
(SANBI) is equi ed o d aw up a s a us epo on biological in asions. The wo ding o he ele an sec ion o
he egula ions is as ollows:
1. The Ins i u e [i.e. SANBI] o a body designa ed by he Ins i u e mus , o he pu pose o epo ing as
con empla ed in sec ion 11(1) (a) (iii) o he Ac , submi a epo on he s a us o lis ed in asi e species o
he Minis e wi hin h ee yea s o he da e on which hese egula ions come in o e ec , and a leas e e y
h ee yea s he ea e [ he egula ions came in o e ec on 1 Oc obe 2014].
2. A epo con empla ed in sub- egula ion (1) mus con ain a summa y and assessmen o :
a. he s a us o lis ed in asi e species and o he species ha ha e been subjec ed o a isk assessmen ; and
b. he e ec i eness o hese egula ions and con ol measu es based in e alia on in o ma ion om:
i. no i i ca ions ecei ed om owne s o land ega ding lis ed in asi e species occu ing on hei land;
ii. pe mi s issued o lis ed in asi e species;
iii. In asi e Species Moni o ing, Con ol and E adica ion Plans ecei ed om o gans o s a e and
managemen au ho i ies o p o ec ed a eas; and
i . eme gency in e en ions and en o cemen ac ions in ol ing lis ed in asi e species issued by he
Minis e .
5. In p epa ing a epo con empla ed in sub- egula ion (1), he Ins i u e mus ca y ou he esea ch and
moni o ing necessa y o iden i y he ma e s con empla ed in sub- egula ion (2).
No e: he “In asi e Species Moni o ing, Con ol and E adica ion Plans” e e ed o in he egula ions a e in ended o be d awn up o
speci i c a eas. Fo he pu poses o his epo hese a e e e ed o as a ea managemen plans. This is dis inc om species managemen
p og ammes which ocus on con olling pa icula species o en ac oss he whole o Sou h A ica.
1.4. ASPECTS OF BIOLOGICAL INVASIONS THAT ARE NOT COVERED
Box 1.1 ou lines wha has o be co e ed in he epo , bu i is wo h explici ly no ing wha is no conside ed. Fi s ,
as he s a us epo ’s p ima y unc ion is o epo on en i onmen al issues, his ini ial epo has a limi ed ocus
on he socio-economic p oblems caused by biological in asions. The mos damaging in asi e species a e human
diseases. These a e no included in his epo . Simila ly, pes s and weeds ha a ec ag icul u al c ops a e a majo
h ea o sus ainable de elopmen , bu a e no wi hin his epo ’s emi unless such axa also impac upon, o
h ea en, na u al ecosys ems.
Secondly, he e is a sui e o indigenous species ha can ha e undesi able impac s ha a e simila o he impac s
caused by alien species, bu which a e p ecipi a ed by changes in land use o o he aspec s o global change.
Examples include bush enc oachmen by indigenous plan s, and he sp ead o many indigenous bi d species
in o u ban a eas. These can p esen pa icula p oblems, bu hei managemen needs o be in he con ex o
hem as indigenous o he egion and as pes s wi hin hei indigenous anges.
Finally, he social bene i s associa ed wi h alien species con ol p og ammes ha a e implemen ed wi h he
addi ional goals o employmen c ea ion and po e y elie a e no co e ed in his epo , as his is no equi ed
in e ms o he egula ions, as well as because he e ha e been no a emp s o da e o quan i y hese bene i s.
Howe e , hese bene i s should ideally be conside ed when e u ns on in es men om con ol p ojec s a e
calcula ed (Box 1.2).
6
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
See Chap e 8 o a mo e de ailed discussion o gaps, challenges, and po en ial di ec ions o u u e epo s.
BOX 1.2 SOCIAL BENEFITS ASSOCIATED WITH INVASIVE ALIEN PLANT CLEARING PROGRAMS
This epo assesses he s a us o biological in asions and he e ec i eness o con ol and egula o y
measu es in Sou h A ica, as equi ed by sec ion 11o he Alien and In asi e Species Regula ions (Box 1.1).
Mos o he alien plan con ol p ojec s ac oss he coun y a e unded by he Wo king o Wa e (W W)
P og amme (Box 6.2), which is an Expanded Public Wo ks p og amme o go e nmen and has he dual
goals o p o iding employmen and de elopmen oppo uni ies o disad an aged indi iduals in u al
a eas, as well as managing in asi e alien species. The social goals, besides p o iding a di ec income o
ens o housands o bene i cia ies, include a emp s o de elop en ep eneu ial and o he skills. W W has
adop ed employmen p ac ices which ensu e ha p e iously disad an aged indi iduals, women, he
you h, and people li ing wi h disabili ies a e gi en p io i y. The magni ude and impac o hese social
bene i s has no been o mally quan i i ed, bu i should be no ed ha hese bene i s need o be
conside ed when de e mining he ull ex en o e u ns on in es men a ising om alien species con ol
p ojec s (see sec ion 6.4.3 o he epo ). This has no been add essed in his s a us epo as he issue alls
ou side o he manda e o his epo , and also because he e a e no eliable es ima es o he magni ude
o he social bene i s.
Bene i cia ies employed by he Wo king o Wa e P og amme in he Eas e n Cape P o ince. Bene i s each o e 30000 people ac oss
Sou h A ica e e y yea (Pho og aph: B. an Wilgen).
2
INDICATORS
Lead au ho s:
John Wilson, B ian an Wilgen
Con ibu ing au ho s:
Ka elyn Faulkne ,
Da id Richa dson,
Seba aolo Rahlao,
Tsungai Zengeya
Chap e summa y
This chap e ou lines he de elopmen o a se o 21 indica o s o assessing
h ee main aspec s o in asions (pa hways, species, and a eas), as well
in e en ions (in e ms o bo h he e ec i eness o con ol measu es, and he
e ec i eness o he egula ions). Fo each indica o , a ac -shee was de eloped,
ou lining how he indica o s a e o be measu ed and p o iding a me hod o
asc ibing a le el o con i dence when assigning alues o indica o s.
Indica o s o pa hways desc ibe he oppo uni ies a ailable o in oduc ion o
and dispe sal wi hin Sou h A ica, as well as he deg ee o which alien species
a e being in oduced along hese pa hways.
Indica o s o species include he numbe and s a us o alien species in he
coun y, he ex en and abundance o hese alien species, and he impac s
caused.
Indica o s o in aded a eas include he numbe o alien species in di e en
a eas, he alien species ichness ela i e o indigenous species ichness, he
abundance o in asi e species ela i e o he abundance o indigenous species,
and he impac o in asions on pa icula a eas.
Indica o s o he in e en ions include an assessmen o key inpu s ( he
egula o y amewo k, he money spen and he planning co e age), ou pu s
( he deg ee and quali y o ea men s applied o pa hways, species and a eas)
and ou comes ( he e ec i eness o ea men s o pa hways, species and a eas,
as well as e u ns on in es men ).
This chap e also p oposes ou high-le el indica o s: 1) he a e o in oduc ion o
new un egula ed species; 2) he numbe o in asi e species ha ha e majo
impac s; 3) he ex en o a ea ha su e s majo impac s om in asions; and (4)
he le el o success in managing in asions.
Acacia pa adoxa (Kanga oo ho n) – John Wilson

14
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
2.1. INTRODUCTION
A se o obus indica o s is needed o p o ide a
comp ehensi e pic u e o he s a e o biological in asions.
While he e has been some p og ess owa ds his goal a
an in e na ional le el (Hawkins e al., 2015, La ombe e al.,
2017), much emains o be done. I was clea ha Sou h
A ica’s i s na ional s a us epo should build on hese
in e na ional ini ia i es, bu i was also necessa y o
de elop addi ional indica o s o co e hose aspec s ha
we e no ye ca e ed o in he de eloping in e na ional
amewo k. In addi ion, he e is a speci i c need o include
indica o s ha di ec ly add ess he epo ing equi emen s
ou lined in he egula ions. Fu he mo e, he e a e no da a
a ailable o accu a ely assign alues o some indica o s o
Sou h A ica, no will i be easible o collec such da a in
he medium- e m. The p ocess o indica o de elopmen
in his a ea will need o con inue bo h in e ms o
undamen al esea ch, and as pa o he de elopmen o a
p ac ical and in o ma i e moni o ing amewo k o
biological in asions in Sou h A ica. As such, he indica o s
p oposed he e cons i u e a comp omise, pa ly om
in e na ional amewo ks, pa ly om i s p inciples, pa ly
simply in e ms o a e l ec ion o which da a a e cu en ly
a ailable, while ensu ing ha he e is alignmen wi h he
equi emen s in he egula ions.
This chap e p esen s a se o indica o s o use in
es ablishing he s a us o biological in asions in Sou h
A ica based on basic in en o y and ecological esea ch and
he moni o ing and epo ing o he e ec i eness o
egula ions and con ol measu es (Figu e 2.1). This chap e
also p esen s a me hodology o asc ibing a le el o
con i dence when assigning alues o hese indica o s.
2.2. THE RATIONALE FOR THE
APPROACH
The phenomenon o biological in asions is caused by a
combina ion o how axa a e mo ed a ound by humans
(in oduc ion dynamics), he ai s o indi idual axa
(in asi eness), and he suscep ibili y o he en i onmen o
EFFECTIVENESS
OF RESPONSES
A se o ou high-le el indica o s has been
de eloped o ack ends in:
A
he a e o in oduc ion o
new un egula ed species
o Sou h A ica
7
PER
YEAR
B
he numbe o in asi e
species ha ha e majo
impac s
107
SPECIES
C
he ex en o Sou h A ica
ha su e s majo impac s
om in asions
1.4%
OF THE LAND AREA
D
he le el o success in
managing in asions
5.5%
The alues assigned o hese indica o s se a
baseline agains which ends in u u e can be
measu ed, wi h he o e all goal being o
implemen con ol and egula o y measu es
ha will imp o e he si ua ion as measu ed
by hese indica o s.
15
CHAPTER 2
I
INDICATORS
in asions (in asibili y). Fo example, he cu en dis ibu ion o in asi e pines in Sou h A ica is a esul o
how pines ha e his o ically been plan ed o o es y, which species ha e pa icula ai s ha p edispose
hem o in ade, and he ac ha some a eas o he coun y do no ha e any indigenous i e-adap ed ee
species and so a e suscep ible o woody plan in asions (e.g. he Cape Flo is ic Region). The explici
conside a ion o biological in asions in e ms o hese h ee aspec s [i.e. pa hways, species (o mo e p ecisely
axa), and a eas] is also c ucially impo an o managemen . Focussing on pa hways is impo an o educe
a es o in oduc ion and sp ead, bu does no add ess cu en in asions. Focussing on species can be highly
e ec i e in educing densi ies o a single species, bu can simply clea he way o o he species o in ade.
In eg a ed and s a egic app oaches a e needed o deal wi h sui es o co-occu ing species in any gi en
a ea, bu i managemen is o be e ec i e in hose a eas, pa hways o in oduc ion need o be managed and
in mos cases bes p ac ice species-speci i c con ol measu es will need o be implemen ed.
The in asion p ocess is commonly ca ego ised in e ms o an in oduc ion-na u alisa ion-in asion
con inuum (Blackbu n e al., 2011). The e a e ou majo in asion s ages – p e-in oduc ion, incu sion,
expansion, and dominance – ha align wi h ou managemen goals – p e en ion, e adica ion,
con ainmen , and impac educ ion. The combina ion o he need o look a indica o s o pa hways,
species and a eas, as well as he need o look a p e-in oduc ion, incu sion, expansion and dominance,
gi es ise o he 3×4 amewo k. This amewo k was he basis o he d a Na ional S a egy on Biological
In asions in Sou h A ica, and is discussed in de ail by Wilson, Pane a & Lindg en (2017). Howe e , he
de elopmen o indica o s o all aspec s o in asions a all in asion s ages s ill equi es some heo e ical
de elopmen . This epo concen a es on indica o s o he h ee aspec s (pa hways, species, and a eas),
and no on he ou s ages (p e-in oduc ion, incu sion, expansion, and dominance), al hough a u u e
epo may seek o de elop he indica o s needed o co e all componen s o he 3 × 4 amewo k.
The e a e, o cou se, many o he ways o concep ualising o ca ego ising biological in asions. Taxonomic,
disciplina y o unc ional lines could also be used, e.g. by conside ing eshwa e i sh in asions and ipa ian
plan in asions as sepa a e p oblems. Al e na i ely, a s a us epo could be di ided in o speci i c biomes,
en i onmen s o ealms. Sou h A ica’s Na ional Biodi e si y Assessmen has, o da e, aken his app oach
and is p esen ed as a se ies o chap e s based on ‘ ealms’ – eshwa e , ma ine, and e es ial. In e ms o
biological in asions, he e is, howe e , no nea sepa a ion be ween aqua ic and e es ial en i onmen s,
no be ween i sh, ogs, and e ns – he essence o he p oblem is he same. I p opagule p essu e can be
educed, will his educe he likelihood o an in asion? Wha a e he impac s? Is a species de i ni ely alien?
Managemen o en needs o conside en i e sys ems, e.g. simul aneously managing eshwa e i sh
in asions and ipa ian plan in asions would lead o a mo e sus ainable ou come han i ei he g oup was
con olled on i s own (Impson, Van Wilgen & Weyl 2013); and he same pa hway (e.g. he pe - ade) can be
esponsible o in oducing ma ine, e es ial and eshwa e o ganisms. So while i is impo an o be able
o epo along geog aphical o axonomic lines, no leas as his is equen ly he le el a which da a a e
collec ed o managemen is implemen ed, i is impo an ha such da a can be agg ega ed o gi e highe
le el indica o s. In his epo , he indica o s hemsel es a e no spli in o geog aphical o axonomic lines,
bu he epo will conside g oupings wi hin each indica o as pe he da a sou ces hemsel es [e.g. he
Sou he n A ican Plan In ade s A las (SAPIA) includes da a on alien plan s ac oss all habi a ypes excep
ma ine and some coas al habi a s].
16
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
Fo he epo o be o alue i should p o ide in o ma ion ha can be used o de e mine how e ec i e
in e en ions ha e been in educing he size o cu en p oblems. The app oach aken in his epo is o assess
he e ec i eness o in e en ions (which is composed o bo h he e ec i eness o con ol measu es and he
e ec i eness o egula ions) in e ms o how hey in l uence aspec s o pa hways, species o a eas. Speci i cally
indica o s a e p esen ed o inpu s (e.g. he amoun o money spen ), ou pu s (i.e. con ol measu es ha a e in
place), and he ou comes (i.e. how e ec i e he con ol measu es a e). In his epo , indica o s a e no , howe e ,
de eloped o : 1) he unde lying p ocesses equi ed o hose in e en ions; o 2) he ul ima e impac o he
in e en ions. In e en ions equi e a sui e o enabling p ocesses (speci i cally: accessibili y o da a and
in o ma ion; o ganisa ional and human capaci y; esea ch; and public awa eness and engagemen ), bu as hese
a e no di ec ly ela ed o ou pu s ha a ec ou comes hey a e no conside ed he e. De eloping indica o s o
hese enabling p ocesses migh be a p io i y o u u e epo s. Secondly, i he implica ions o any in e en ion
o he b oade Sou h A ican communi y a e o be assessed, he e mus be a link made o gene al en i onmen al
and socio-economic indica o s, i.e. he impac . In his epo , his link is no made explici no is an a emp made
o de elop indica o s speci i cally o his (as i is mo e app op ia e o co-op exis ing sec o -speci i c indica o s).
I is an icipa ed ha de eloping he link be ween wha is done in his epo (i.e. assessing impac in e ms o
speci i c ou come indica o s and changes o he indica o s o he s a e o biological in asions) and b oade
socie al indica o s o impac will be a majo ocus o u u e epo s.
In line wi h in e na ional p oposals (GEO BON, 2015, La ombe e al., 2017), he s a us epo ed should be modula .
I esou ces pe mi , high-le el da a can be collec ed wi hou comp omising he abili y o compa e wi h si ua ions
whe e ewe da a o esou ces a e a ailable. Fo example, accu a e dis ibu ion da a a e a ailable o bi ds, bu
no o mic obes (Chap e 4).
Sni e dogs a e equen ly used o de ec
illegal impo s, including alien species
17
CHAPTER 2
I
INDICATORS
2.3. CONFIDENCE LEVELS
Indica o s a e, o cou se, abs ac ions o he eal wo ld and he eal wo ld does no always i nea ly in o hese
abs ac ions. The e will be some unce ain y in any alues p esen ed whe he because o how hey we e
measu ed o ha he subjec s o measu emen hemsel es a e a iable.
This epo ollows b oad guidelines used in ela ed en i onmen al assessmen s and classi i es con i dence le el
o any o he assessmen s in o h ee b oad ca ego ies (Table 2.1).
TABLE 2.1 Guidance ega ding he use o he con i dence a ing [adap ed om Hawkins e al., 2015, modi i ed om he EPPO pes
isk assessmen decision suppo scheme (Alan MacLeod 09/03/2011. e ised 28/04/2011. copied om CAPRA, e sion 2.74; 2)].
Exac de i ni ions a e gi en o each indica o in Appendix 1.
CONFIDENCE LEVEL DEFINITION
HIGH
The e is di ec ele an obse a ional e idence o suppo he assessmen ;
AND
obse a ions a e a he ele an spa ial o empo al scale;
AND
he da a sou ces a e eliable and o good quali y;
AND
he in e p e a ion o da a and in o ma ion is s aigh o wa d;
AND
da a and in o ma ion a e no con o e sial o con adic o y.
MEDIUM
The e is some di ec obse a ional e idence o suppo he assessmen , bu some
in o ma ion is in e ed;
AND/OR
obse a ions a e eco ded a a spa ial o empo al scale which may no be a he ele an
scale bu ex apola ion o downscaling o he da a is conside ed eliable, o o emb ace
li le unce ain y;
AND/OR
he in e p e a ion o he da a is o some ex en ambiguous o con adic o y.
LOW
The e is no di ec obse a ional e idence o suppo he assessmen , e.g. only in e ed da a
ha e been used as suppo ing e idence;
AND/OR
obse a ions a e eco ded a a spa ial o empo al scale which is unlikely o be ele an o
he scale equi ed, and ex apola ion o downscaling o he da a o ele an scales is
conside ed un eliable o o emb ace signi i can unce ain ies;
AND/OR
e idence is poo and di i cul o in e p e , e.g. because i is s ongly ambiguous;
AND/OR
he in o ma ion sou ces a e conside ed o be o low quali y o con ain in o ma ion ha is
un eliable.
18
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
2.4. INDICATORS USED IN THIS REPORT
In his sec ion, he indica o s used in his epo a e de i ned in he con ex o he o e all epo ing amewo k
(Figu e 2.1). A comple e se o indica o s o pa hways, species and a eas, as well as in e en ions (e ec i eness o
con ol measu es and e ec i eness o egula ions) a e p esen ed in he sec ions ha ollow. Fu he de ail on each
indica o is p o ided in Appendix 1, including he in ended use and in e p e a ion o he indica o , he
implica ions o a change in he indica o , and he ecommended o ma o p esen a ion. In addi ion, Appendix 1
p o ides in o ma ion on sou ce da a, speci i es he p ocedu e o be ollowed when calcula ing he indica o ’s
alue, and iden i i es he uni s in which he indica o is exp essed.
Basic
in en o y
and
ecological
esea ch
Assess implica ions and
o mula e app op ia e policy
Se goals and implemen
managemen measu es
Moni o ing
and e alua ion
Chap e 1:
In oduc ion
Chap e 8:
Key Gaps
Chap e 2:
Indica o s
Chap e 9:
Key messages
Chap e 3:
Pa hways
Chap e 4:
Species
Chap e 5:
A eas
INTERVENTIONS
Chap e 6: Con ol measu es
Chap e 7: Regula ions
Ou comes Ou pu s Inpu s
FIGURE 2.1 The s uc u e used in his epo . Indica o s a e de eloped in his chap e o each o he i e subsequen chap e s
– pa hways, species, a eas, e ec i eness o egula ions, and e ec i eness o con ol measu es. The e ec i eness o egula ions and
he e ec i eness o con ol measu es a e conside ed join ly he e as in e en ions, and a e assessed in e ms o indica o s o inpu s,
ou pu s, and ou comes. In chap e 8 key gaps a e iden i i ed and, in chap e 9, based on he insigh s om he o he chap e s,
ecommenda ions o policy make s and manage s a e de eloped. The indica o s do no , howe e , co e e e y hing in he epo . In
pa icula , he e a e se e al addi ional ac o s ha mus be epo ed on in e ms o he egula ions, bu do no di ec ly in l uence he
indica o s o he ou comes o he in e en ions and in and o hemsel es do no p o ide in o ma ion as o whe he in e en ions a e
succeeding o no . The e a e also se e al enabling p ocesses ha a e no discussed in his epo (accessibili y o da a and in o ma ion;
o ganisa ional and human capaci y; esea ch; and public awa eness and engagemen ). See sec ion 8.3 o a discussion on how hey
migh be inco po a ed in o u u e epo s.
2.4.1. Pa hways
This epo conside s ou indica o s o pa hways (Table 2.2) ha assess he p ominence o he pa hway and he
a e a which axa a e in oduced along he pa hway, o bo h in oduc ion in o he coun y, and dispe sal wi hin
he coun y: 1) in oduc ion pa hway p ominence; 2) in oduc ion a es; and he co esponding 3) wi hin-coun y
pa hway p ominence; and 4) wi hin-coun y dispe sal a es.

19
CHAPTER 2
I
INDICATORS
A a basic le el, he indica o s use he hie a chical scheme o pa hway classi i ca ion adop ed by he Con en ion
on Biological Di e si y (CBD), based on six b oad ca ego ies and 44 sub-ca ego ies (Appendix 2; Scale a e al.,
2016). I da a a e a ailable, spa ially explici ec o s can be used o acili a e p ecise esponse and managemen .
Simila ly a a basic le el in oduc ion a es a e in e ms o he numbe o alien species in oduced, al hough
ideally he e would be es ima es o colonisa ion and p opagule p essu e o each in oduc ion e en .
TABLE 2.2 Indica o s o epo ing on he s a us o in oduc ion and dispe sal pa hways (indica o alues a e es ima ed in
Chap e 3). Fo ull de ails o how o calcula e he indica o s, see Appendix 1.
INDICATOR METRIC
BASIC ADVANCED
1. In oduc ion pa hway
p ominence
1.1. Fi e quali a i e
ca ego ies indica ing he
p ominence o CBD
pa hway sub-ca ego ies
(No known; Pa hway no
p esen ; Mino ; Mode a e;
Majo )
1.2. A anked o de o
pa hways in e ms o hei
p ominence
1.3. Spa ially explici ec o s
ha de ail he amoun ,
numbe and alue o goods
o essels mo ing in o he
coun y pe pa hway, wi h
in o ma ion on he sou ces,
ou es, des ina ions, and
imings
2. In oduc ion a es 2.1. The o al numbe o
alien species in oduced
h ough each CBD pa hway
sub-ca ego y o e all ime
2.2. Fi e ca ego ies
demons a ing changes o e
a ecen pe iod o ime (e.g.
since he 1980s o in he pas
decade) in he numbe o
species in oduced h ough
each pa hway (No known;
No in oduc ions; Inc ease;
Dec ease; Minimal change)
2.3. Numbe o indi iduals
o each species in oduced
h ough he pa hways and
place and da e o
in oduc ion
3. Wi hin-coun y
pa hway p ominence
3.1.–3.3. As o 1. In oduc ion pa hway p ominence, o wi hin-coun y dispe sal a he
han in oduc ions
4. Wi hin-coun y
dispe sal a es
4.1.–4.3. As o 2. In oduc ion a es, o wi hin-coun y dispe sal a he han in oduc ions
2.4.2. Species
This epo uses species as he p ima y biological uni in line wi h he majo i y o he axa lis ed unde he
Na ional En i onmen al Managemen : Biodi e si y Ac , Alien and In asi e Species Regula ions ( he NEM:BA A&IS
Regula ions). Howe e , se e al axa a e lis ed a le els o he han species, in asions can occu a he gene le el
(e.g. esul ing in he loss o indigenous species h ough hyb idisa ion), and undamen ally biological in asions
a e a popula ion le el phenomenon. These issues migh be a ocus o u u e epo s.
The p oposed sys em o global obse a ion and moni o ing o alien species iden i i ed h ee essen ial a iables
o moni o ing species – alien s a us, occu ence and impac (La ombe e al., 2017). In his epo elemen s o
de e mining alien s a us a e combined wi h a e y coa se ca ego isa ion o occu ence (5. Numbe and s a us o
alien species). I a species is p esen and clea ly alien, he nex pa o de i ning s a us is o de e mine whe e i is,
and how common i is (indica o s 6. Ex en o alien species; and 7. Abundance o alien species). Finally, in di ec
alignmen wi h he p oposed global scheme is indica o 8. Impac o alien species (Table 2.3).
20
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
Fo he Numbe and s a us o alien species, a a basic le el his is simply he numbe o in asi e species (as hese
a e he p ima y ocus o mos managemen e o s). A a mo e ad anced le el all alien species should be lis ed
and placed in o ele an ca ego ies along he in oduc ion-na u alisa ion-in asion con inuum (Blackbu n e al.,
2011), bu in all cases he e a e wo decisions o be made: 1) is a species alien o indigenous?; and i i is alien,
2) is i p esen in he egion? The i s pa , i.e. de e mining na i i y, is o en ai ly s aigh - o wa d, bu in he
case o cosmopoli an species i migh be impossible o ace he indigenous ange, and o o he axa, (mic obes
and ungi in pa icula ) de e mining indigenous anges equi es ex ensi e sampling and molecula analysis
wi h li le gua an ee o success (Wood, 2017). De e mining p esence can be s aigh o wa d in many cases, bu
highly p oblema ic in o he s. The minimum s anda ds equi ed o a species o be included on a lis o alien
species a y be ween lis s, and in many cases no physical specimen is equi ed. Simila ly he e is o en, a leas
his o ically, no equi emen o legal mechanism whe eby delibe a ely in oduced species needed o be
eco ded. Impo pe mi s alone a e no su i cien p oo o p esence as pe mi s can be issued, bu no ac ually
used. Mo eo e alien species, e en hose ha ha e es ablished, do no always pe sis (Simbe lo & Gibbons,
2004). Fo example, Te apygus nige (black sea u chin) was eco ded in Sou h A ica in 2007, bu he a ea whe e
i was p esen has been ans o med. Based on a ecen su ey, he species is conside ed o no longe be
p esen in he coun y (Mabin, Wilson & Robinson, 2015). This poin s o he need o documen when, whe e,
and on wha basis, he p esence o a axon was no ed. Simila ly, he e idence o decla ing ha a species is
absen needs o be made clea . Such in o ma ion is impo an o policy, as i is a key de e minan when
e alua ing applica ions o impo species.
By hei na u e, lis s o alien species a e dynamic as axa a e in oduced, na u alise, become in asi e, disappea
om an a ea, o a e e adica ed. The e a e a ew addi ional issues ha mean lis s change o e ime, e.g. c yp ic
axa a e iden i i ed as aliens, o he e a e axonomic changes (Jacobs e al., 2017, Pyšek e al., 2013). Consequen ly,
lis s need o be dynamic, and changes need o be clea ly documen ed based on de i ned minimum s anda ds
(Mu ay e al., 2017). The le el o con i dence ha any pa icula species is s ill p esen should decline wi h ime
since he las specimen was collec ed o he las eco ded i eld sigh ing.
In e ms o alien species dis ibu ions, he Ex en o alien species can be assessed using occupancy a b oad spa ial
scales. A he b oades scale his will be occupancy a p o incial, biome, p ima y ca chmen scale o ma ine
eco egion, bu da a a e o en a ailable a a qua e -deg ee g id cell (~630–710 km2 a he la i ude o Sou h A ica)
and so his is used he e. The measu e o he Abundance o alien species will a y depending on he ype o o ganism.
Fo mobile axa his migh be an es ima e o numbe s o indi iduals, while o sessile o ganisms i migh be a
measu e o how much o he a ea is occupied a a i ne scale (i.e. condensed canopy a ea). These da a a e, o cou se,
no always a ailable o he da a a e insu i cien o p o ide eliable es ima es. The e o e a ca ego ical app oach
migh be needed (e.g. a e, occasional, o abundan ). Da a o ex en and abundance come om physical
collec ions, mapping (a las) p ojec s and dedica ed su eys. Each me hod has i s own s eng hs and biases
(Robinson, Cumming & E asmus, 2010), and he e o e a ec he con i dence le el wi h which es iam es a e gi en.
Finally, he Impac o alien species needs o be measu ed bo h in en i onmen al and socio-economic e ms.
Recen ly, he e has been subs an ial p og ess in de eloping consis en me ics ha can be used o sco e he
impac s o pa icula alien axa, in pa icula h ough he En i onmen al Impac Classi i ca ion o Alien Taxa
(EICAT) scheme (Blackbu n e al., 2014, Hawkins e al., 2015) ha has ecen ly been adop ed by he IUCN and he
mo e ecen Socio-Economic Impac Classi i ca ion o Alien Taxa Scheme (SEICAT; Bache e al., 2018). EICAT
p o ides a consis en me hod o a ing impac as minimal, mino , mode a e, majo o massi e, wi h in e p e a ions
21
CHAPTER 2
I
INDICATORS
p o ided o di e en impac mechanisms ( o example compe i ion, p eda ion o he bi o y, o chemical,
physical o s uc u al ea u es o he ecosys em). The accu a e assessmen o species wi hin his sys em equi es
con i ma ion ha he species is alien, and he a ailabili y o adequa e da a o con i den ly place he species in o
one o he a ing ca ego ies. SEICAT is simila in s uc u e, wi h impac s measu ed in e ms o how alien species
a ec wha people do.
TABLE 2.3 Indica o s used o epo ing on he s a us o alien species (indica o alues a e es ima ed in Chap e 4). Fo ull
de ails o how o calcula e he indica o s, see Appendix 1.
INDICATOR METRIC
BASIC ADVANCED
5. Numbe and s a us o
alien species
5.1. Numbe o in asi e
species
5.2. Numbe o alien
species in one o h ee
ca ego ies (alien bu no
na u alised, na u alised bu
no in asi e, in asi e)
5.3. Numbe o species in
each o he 12 di e en
s ages iden i i ed in he
Uni i ed F amewo k o
Biological In asions
6. Ex en o alien species 6.1. Numbe o la ge-scale
na ional subdi isions
(p o inces, p ima y
ca chmen s o bio egions
as app op ia e) occupied
pe species
6.2. Numbe o i ne -scale
na ional subdi isions
(qua e -deg ee g id cells o
hec ads) occupied pe
species
6.3. Range size o each
species (e.g. km2 o ha)
7. Abundance o alien
species
7.1. Ca ego ical measu e o
abundance pe species in
one o i e ca ego ies
(absen , a e, occasional,
abundan , no known)
7.2. Numbe o indi iduals
o mobile o ganisms o
condensed a ea occupied
o sessile o ganisms
7.3. Abundance es ima es
di ided in o app op ia e
s age o age coho s. A a
basic le el numbe s o
indi iduals which a e
ep oduc i e o no
8. Impac o alien species 8.1. Ca ego ical ac o wi h eigh le els. A single alue is
p esen ed which is he maximum cu en eco ded impac
in Sou h A ica in e ms o ei he he En i onmen al Impac
Classi i ca ion o Alien Taxa (EICAT) o Socio-economic
Impac Classi i ca ion o Alien Taxa (SEICAT) schemes
(Bache e al., 2018, Blackbu n e al., 2014)
8.2. The cu en and
maximum e e eco ded
EICAT and SEICAT sco es o
each possible impac
mechanism o each species
in Sou h A ica
2.4.3. A eas
The e a e a a ie y o ways o ca ego ise a eas. While adminis a i e egions a e use ul o managemen , hey do
no necessa ily ollow biogeog aphical zones. Bu e en biogeog aphical zones, as de i ned by he p esence o
indigenous species, a e no necessa ily use ul o app op ia e as he p ocesses ha se biogeog aphic bounda ies
can di e om hose ha de e mine spa ial pa e ns o alien species (Rouge e al., 2015). As such, a eas a e
o en de i ned o p ac ical planning easons, e.g. municipali ies o na ional pa ks, o a simple g id is used, e.g.
qua e deg ee g id cells [QDGCs, o en also (inco ec ly) called qua e deg ee squa es, QDSs]. In Sou h A ica
e ia y ca chmen s a e also equen ly used (e.g. Roux e al., 2008), bu while pe haps mo e ecologically ele an ,
his is no he scale a which da a on biological in asions in he coun y has been collec ed. The e o e in his
epo wo le els a e conside ed: b oad scale (p o inces, biomes, ma ine egions, o p ima y ca chmen s as
app op ia e) and QDGCs. These scales a e la gely dic a ed by he a ailabili y o da a.
22
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
The i s indica o is simply he o al numbe o alien species in a gi en a ea (9. Alien species ichness, Table 2.4).
A a basic le el his is he numbe o in asi e species (as da a a e mos ly collec ed on in asi e species a he
han hose in cap i i y o cul i a ion and he in asi e species a e usually hose o mos di ec conce n). A
mo e ad anced le els, he numbe o alien species a di e en s ages o he Uni i ed F amewo k is epo ed
on. The assump ion is gene ally made ha i a species is in asi e in one a ea and eco ded in ano he i is also
in asi e he e, bu his would equi e some e i nemen and ideally a ea-speci i c assessmen s o in oduc ion
s a us a e equi ed.
While Alien species ichness p o ides a use ul measu e o he in asions, i does no ake in o accoun o e all
di e ences in species ichness in an a ea. The e o e, Ca o d e al. (2012) ecommend addi ional ela i e
measu es, codi i ed he e as 10. Rela i e alien species ichness and 11. Rela i e in asi e abundance (Table 2.4). The
ela ionship be ween Rela i e alien species ichness and Rela i e in asi e abundance can indica e he p esence
o dominan in asi e species and he ajec o y o in asion o e ime (Ca o d e al., 2012). In his epo , he
dis inc ion is made be ween Rela i e alien species ichness and Rela i e in asi e species abundance, as he
o me can gi e an indica ion o he po en ial size o u u e p oblems ( aking all alien species in o accoun ),
bu he la e is a me ic o he cu en s a us o in asions. A a basic le el Rela i e in asi e abundance is
measu ed quali a i ely (i.e. no known; in asi e- ee; mino ; mode a e; ex ensi e; dominan ), bu whe e da a
allow a quan i a i e measu e o he o al abundance is p e e ed (e.g. pe cen age o co e , biomass, o
numbe s o indi iduals).
The impo ance o he Impac o in asions wi hin a ce ain a ea will di e depending on he a ea- ype. Fo
example, in p o ec ed a eas wi h high indigenous biodi e si y, he deg ee o h ea o indigenous biodi e si y
would be he main c i ical indica o , whe eas in o he a eas educ ion in ecosys em se ices (in e ms o bene i
l ows and i nancial l ows) o impac s on human li elihoods would be mo e impo an . The e is no accep ed,
uni i ed sys em o he classi i ca ion o he impac s o all biological in asions on a pa icula a ea. None heless,
se e al s udies ha e quan i i ed he impac o pa icula in asions on he o e all biodi e si y o an a ea (e.g. Van
Wilgen e al., 2008); and educ ions in pa icula ecosys em se ices, exp essed bo h in e ms o bene i l ows
(e.g. he amoun o wa e l owing om a ca chmen , o he numbe o li es ock suppo ed on a angeland, Van
Wilgen e al., 2008) o i nancial l ows ( he alue o he bene i s in mone a y e ms, De Lange & Van Wilgen 2010).
Finally, he e ec s o in asi e species can be assessed in e ms o hei impac on human li elihoods in a gi en
a ea (Shackle on e al., 2007).
In he absence o o he indica o s, we p opose o measu e he Impac o in asions o pa icula a eas o Sou h
A ica in e ms o he educ ion in wa e esou ces, g azing capaci y and biodi e si y (Table 2.4). Simila o he
ca ego ies unde he EICAT scheme, we p opose ha educ ions in he se ice o < 2% a e mino ; 2–10% will be
mode a e; 10–50% will be majo ; and > 50% will be massi e. These cu -o s a e somewha a bi a y and, unlike
EICAT, hey do no ake he pe manence o he change in o accoun . We p opose ha a na ional s a us epo
should assess hese educ ions o pa icula ecosys em se ices o which a leas some es ima es ha e been
made, o whe e models exis o make hem. Based on an EICAT assessmen , i should also be possible o con e
in o ma ion on species-impac s a us in o he app op ia e a ea-impac s a us o a a ge egion. This is, howe e ,
clea ly a opic whe e mo e wo k is equi ed. I would be desi able o de elop ad anced indica o s ha could
exp ess he e ec s o educ ions in ecosys em se ices in economic o social e ms (De Lange & Van Wilgen,
2010), ideally again linking concep ually wi h he EICAT scheme.
29
CHAPTER 3
I
PATHWAYS OF INTRODUCTION
The in oduc ion and dispe sal o alien species a e in l uenced by a numbe o in e ac ing a iables (including he
en i onmen and species ai s). In pa icula , ends in socio-economic ac o s (e.g. managemen in e en ions,
ashions, economic condi ions) play an impo an ole in shaping he pa hways o in oduc ion and dispe sal,
and de e mining how hey change o e ime (Hulme e al., 2008; Essl e al., 2011, 2015a; Oja ee e al., 2017; Saul
e al., 2017; Seebens e al., 2017; Zie i z e al., 2017). Fo example, changes o global ene gy ma ke s migh esul
in an inc ease in he numbe o ma ine species in oduced o he USA h ough he elease o ballas wa e
(Holze e al., 2017); and while acclima isa ion socie ies acili a ed he elease o many alien species in New
Zealand, Aus alia and he USA, a dec ease in he public and scien i i c suppo o hese socie ies du ing he
wen ie h cen u y led o a dec ease in hese ac i i ies (Seebens e al., 2017).
I is, he e o e, impo an o unde s and he po en ial pa hways o in oduc ion and he ole hey play, as well as
how impo an hey migh be o he in oduc ion o alien o ganisms. The ou indica o s de eloped o ack
hese ac o s a e: (1) In oduc ion pa hway p ominence, (2) In oduc ion a es, (3) Wi hin-coun y pa hway
p ominence, and (4) Wi hin-coun y dispe sal a es (Table 2.2). In oduc ion and Wi hin-coun y pa hway p ominence
conside he size o he pa hways o in oduc ion and dispe sal bu do no ake in o accoun he impo ance o
he pa hways o he in oduc ion o dispe sal o alien o ganisms. In oduc ion a es and Wi hin-coun y dispe sal
a es conside he impo ance o he pa hways o he in oduc ion and dispe sal o new alien o ganisms.
In o ma ion on how hese indica o s ha e changed o e ime and o ecas s o u u e changes no only in o m
he de elopmen o policies and managemen s a egies bu a e i al when e alua ing he e ec i eness o
pa hway- ela ed con ol measu es.
The s a us o he pa hways o in oduc ion in Sou h A ica and how hey ha e changed o e ime has been
ecen ly assessed using his o ical in oduc ion da a (see Faulkne e al., 2016a). Building on his wo k, his epo
e i nes he analysis using he pa hway ca ego isa ion scheme adop ed by he CBD, and his o ical in oduc ion
and socio-economic da a we e ob ained o popula e he ou indica o s discussed abo e. These indica o s we e
used o e alua e cu en pa hway s a us and his o ical changes o he pa hways, and whe e possible, socio-
economic o ecas s we e ob ained o ge an indica ion o how hese pa hways migh change in u u e. Finally,
he e ec i eness o pa hway ela ed con ol measu es is e alua ed and sou ces o unce ain y add essed
(including knowledge gaps). The e ec i eness o pa hway ela ed con ol measu es and egula ions a e discussed
in Chap e 6 and 7 espec i ely.
Facili y o mass- ea ing biological con ol agen s – Kim Wea e

30
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
MECHANISM
OF ENTRY PATHWAY
CATEGORY PATHWAY SUBCATEGORY IR CHANGE
IN IR IPP FORECAST CONTROL
INCREASING HUMAN ROLE
Biological con ol
111 Mod E
E osion con ol/dune s abilisa ion
68 NK NK NK NK
Fishe y in he wild
15
X
Maj NK E
Release in
na u e
Hun ing
30 Mod /N/I
Landscape/ l o a/ auna “imp o emen ” in he wild
8
X
PNP
–
P
In oduc ion o conse a ion pu poses o wildli e managemen
0
X
NK NK NK
Release in na u e o use o he han abo e
8 NK NK NK NK
O he in en ional elease
0
X
NK NK NK
Ag icul u e
91 NK Maj NK
Aquacul u e/ma icul u e
12
X
Min E
Bo anical ga den/zoo/aqua ia
3
X
Min NK E
Pe /aqua ium/ e a ium species
22
–
Min NK N/I
Fa med animals
5
X
Maj NK E
COMMODITY Escape om
con i nemen
Fo es y
30 NK Maj NK NK
Fu a ms
1
X
Min NK E
Ho icul u e
237 NK Mod NK
O namen al pu pose o he han ho icul u e
1
X
NK NK E
Resea ch and ex-si u b eeding
4 NK Min NK NK
Li e ood and li e bai s
5
X
NK NK E
O he escape om con i nemen
72 NK NK NK NK
Con aminan nu se y ma e ial
3 NK Mod NK NK
Con amina ed bai
0
X
NK NK NK
Food con aminan
7 NK Maj NK NK
Con aminan on animals
9
–
Maj NK N/I
T anspo –
Con aminan
Pa asi es on animals
13
–
Maj NK N/I
Con aminan on plan s
20
–
Mod NK N/I
Pa asi es on plan s
2
–
Mod NK N/I
Seed con aminan
8 NK Mod NK NK
Timbe ade
10 NK Maj NK NK
T anspo a ion o habi a ma e ial
6
–
NK NK N/I
Angling/ i shing equipmen
0
X
Maj N/I
Con aine /bulk
0
X
Mod NK
Hi chhike s in o on ai plane
5 NK Mod NK
Hi chhike s on ship/boa
21
–
Mod N/I
TRANSPORT
VECTOR
T anspo –
S owaway
Machine y/equipmen
0
X
NK NK N/I
People and hei luggage/equipmen
0
X
Maj NK
O ganic packing ma e ial, in pa icula wood packaging
1 NK NK NK NK
Ship/boa ballas wa e
51
–
Mod N/I
Ship/boa hull ouling
68 Mod N/I
Vehicles
1 NK Maj NK N/I
O he means o anspo
0
X
NK NK N/I
NATURAL
SPREAD
Co ido
In e connec ed wa e ways/basins/seas
0
X
Min
–
N/I
Tunnels and land b idges
0
X
Min
–
N/I
Unaided Na u al dispe sal ac oss bo de s o in asi e alien species
ha ha e been in oduced h ough pa hways 1 o 5
9
–
Maj N/I
F IGURE 3.1 The cu en and o ecas ed s a us o he pa hways o in oduc ion and he e ec i eness o con ol measu es. IR: a es o
in oduc ion o he pa hways (i.e. numbe o axa in oduced o e all ime), Change in IR: changes o he a e o in oduc ion in he las ull
decade in compa ison o ha o he p e ious decade (NK: no known;  inc ease;  dec ease;
–
minimal change;
X
no in oduc ions),
IPP: in oduc ion pa hway p ominence (NK: no known; PNP: pa hway no p esen ; Min: minimal; Mod:mode a e; Maj:majo ), o ecas ed
changes o in oduc ion pa hways (NK: no known;  inc ease;  dec ease;
–
minimal change;  /  inc ease o dec ease), and he
e ec i eness o con ol measu es (NK: no known; N/I: none/ine ec i e; E: E ec i e; P:Pe manen ). The pa hways we e ca ego ised using
he scheme adop ed by he Con en ion on Biological Di e si y (CBD, 2014). Fo de ails see sec ion 3.5 and Table A2.1.
31
CHAPTER 3
I
PATHWAYS OF INTRODUCTION
3.2. DATA SOURCES
In o duc ion and Wi hin-coun y pa hway p ominence we e assessed using socio-economic in o ma ion collec ed
om a wide ange o sou ces. In o ma ion on he pa hways o in oduc ion, da e o in oduc ion and egion o
o igin o axa in oduced o Sou h A ica we e ob ained om he da ase p esen ed in Faulk ne e al. (2015) and
we e used o assess In oduc ion a es. In o ma ion on he species dispe sing h ough he pa hways o dispe sal
was ob ained om he li e a u e and used o assess Wi hin-coun y dispe sal a es. Socio-economic da a we e
ob ained om a numbe o sou ces in o de o o ecas u u e changes o he pa hways o in oduc ion. All da a
sou ces a e shown in Table 3.1.
TABLE 3.1 Da a sou ces used in he assessmen o he s a us o he pa hways o in oduc ion and dispe sal o Sou h A ica.
Sou ces wi h an as e isk (*) con ibu ed o he da ase p esen ed in Faulk ne e al. (2015).
DATA SOURCE SCALE OF
COVERAGE DESCRIPTION
LEVEL OF
CONFIDENCE BASED
ON COMPLETENESS
AND ACCURACY
INDICATOR INFORMED
BY THESE DATA
ACSA passenge and
ai c a s a is ics (Ai po s
Company Sou h A ica,
2017)
Na ional Socio-economic in o ma ion on ai
a i c
High 1. In oduc ion pa hway
p ominence
3. Wi hin-coun y
pa hway p ominence
Ag icul u al Resea ch
Council-Plan P o ec ion
Resea ch Ins i u e (2017)
Con inen al In o ma ion on he in oduc ion and
sp ead o Spodop e a ugipe da in A ica
(no e: gi en i s ecen in oduc ion his
species is no included in he species
lis s in Appendix 3)
Medium 2. In oduc ion a es
Apple on (2003)* Na ional His o ical in oduc ion da a o
eshwa e molluscs
Medium 2. In oduc ion a es
B omilow (2010)* Na ional His o ical in oduc ion da a o plan s Medium 2. In oduc ion a es
CITES ade da abase
(UNEP Wo ld
Conse a ion Moni o ing
Cen e, 2017)
Global Socio-economic in o ma ion on he
numbe o animals impo ed o
pe sonal use, bo anical ga den/zoo
pu poses and scien i i c pu poses
Low 1. In oduc ion pa hway
p ominence
Cock e al. (2016) Global In o ma ion on insec s eleased o
biologically con ol o he insec s
High 2. In oduc ion a es
DAFF Diagnos ic Impo
In e cep ion Da abase
(Depa men o
Ag icul u e, Fo es y and
Fishe ies, 2017)
Na ional In e cep ion da a o impo ed plan s,
ood, seed and habi a ma e ial
Medium 2. In oduc ion a es
De Moo & B u on (1988)* Regional His o ical in oduc ion da a o
eshwa e i sh, Ciliopho a, Cnida ia and
Pla yhelmin hes
Medium 2. In oduc ion a es
Dean (2000)* Regional His o ical in oduc ion da a o bi ds, as
well as in o ma ion on dispe sal o
Co us splendens
Medium 2. In oduc ion a es
4. Wi hin-coun y
dispe sal a es
Depa men o
Ag icul u e, Fo es y and
Fishe ies (2015)
Na ional Socio-economic in o ma ion on seed
impo s and p oduc ion
High 1. In oduc ion pa hway
p ominence
Depa men o
Ag icul u e, Fo es y and
Fishe ies (2016a)
Con inen al In o ma ion on he in oduc ion and
sp ead o Tu a absolu a in A ica
Medium 2. In oduc ion a es
Depa men o
Ag icul u e, Fo es y and
Fishe ies (2016b)
Con inen al In o ma ion on he in oduc ion and
sp ead o Tu a absolu a in A ica
Medium 2. In oduc ion a es
32
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
DATA SOURCE SCALE OF
COVERAGE DESCRIPTION
LEVEL OF
CONFIDENCE BASED
ON COMPLETENESS
AND ACCURACY
INDICATOR INFORMED
BY THESE DATA
Depa men o Home
A ai s (2017)
Na ional In o ma ion o Sou h A ican po s
o en y
High 1. In oduc ion pa hway
p ominence
Depa men o T anspo
(2016)
Na ional Socio-economic in o ma ion on Sou h
A ican ai po s
High 1. In oduc ion pa hway
p ominence
Dippenaa -Schoeman &
Ha ey (2000)*
Na ional His o ical in oduc ion da a o
A achnida
Medium 2. In oduc ion a es
FAO (2016a) Global Socio-economic in o ma ion on i shing Medium 1. In oduc ion pa hway
p ominence
FAOSTAT da abase o he
Food and Ag icul u e
O ganisa ion o he Uni ed
Na ions (FAO, 2017)
Global Socio-economic in o ma ion on ood
impo s and on he ag icul u e, li es ock
a ming and o es y sec o s
Medium 1. In oduc ion pa hway
p ominence
Fishs a J da abase o he
Food and Ag icul u e
O ganisa ion o he Uni ed
Na ions (FAO, 2016b)
Global Socio-economic in o ma ion on he
i shing and aquacul u e sec o s
Medium 1. In oduc ion pa hway
p ominence
Fu F ee (2017) Na ional Socio-economic in o ma ion on u
a ming
Low 1. In oduc ion pa hway
p ominence
Ge mishuizen e al. (2006)* Na ional His o ical in oduc ion da a o plan s Medium 2. In oduc ion a es
Guimapi e al. (2016) Con inen al In o ma ion on he in oduc ion and
sp ead o Tu a absolu a in A ica
Medium 2. In oduc ion a es
Hende son (2001)* Na ional His o ical in oduc ion da a o plan s Medium 2. In oduc ion a es
He be (2010)* Na ional His o ical in oduc ion da a o e es ial
molluscs
Medium 2. In oduc ion a es
Hu ley e al. (2012) Na ional In o ma ion on he in oduc ion and
dispe sal o Si ex noc ilio wi hin Sou h A ica
Medium 4. Wi hin-coun y
dispe sal a es
IMF ade o ecas
s a is ics (In e na ional
Mone a y Fund, 2016)
Global Socio-economic in o ma ion on he
olume o impo ed goods
Medium 1. In oduc ion pa hway
p ominence
Klein (2011)* Na ional His o ical in oduc ion da a o biological
con ol agen s eleased o con ol alien
plan species
High 2. In oduc ion a es
Leibold & Van Zyl (2008) Na ional Socio-economic in o ma ion on i shing Medium 1. In oduc ion pa hway
p ominence
Le e (2005) Global In o ma ion on he sp ead o bi d
species wi hin Sou h A ica
Medium 4. Wi hin-coun y
dispe sal a es
Long (1981) Global His o ical in oduc ion da a o bi ds Medium 2. In oduc ion a es
Long (2003)* Global His o ical in oduc ion da a o mammals Medium 2. In oduc ion a es
Ma in & Coe zee (2011) Na ional In o ma ion on he sp ead o aqua ic
plan species wi hin Sou h A ica
High 4. Wi hin-coun y
dispe sal a es
Mead e al. (2011)* Na ional His o ical in oduc ion da a o ma ine axa Medium 2. In oduc ion a es
Measey e al. (2017) Regional In o ma ion on he dispe sal and sp ead
o amphibian species wi hin Sou h A ica
High 4. Wi hin-coun y
dispe sal a es
Middle on (2015) Na ional Socio-economic in o ma ion on
ho icul u e
High 1. In oduc ion pa hway
p ominence
Mo an, Ho mann &
Zimme mann (2013)
Na ional In o ma ion on he wi hin-coun y
dispe sal o biological con ol agen s
High 4. Wi hin-coun y
dispe sal a es
OpenS ee Map
con ibu o s (2017)
Global Spa ial da a on Sou h A ica’s oad and
ail ne wo ks
High 3. Wi hin-coun y
pa hway p ominence
Picke & G i i hs (2011)* Na ional His o ical in oduc ion da a o a wide
a ie y o animals, including i sh, bi ds,
c us aceans, molluscs, insec s and
mammals. In o ma ion on he dispe sal
and sp ead o species wi hin he coun y
Medium 2. In oduc ion a es
4. Wi hin-coun y
dispe sal a es
33
CHAPTER 3
I
PATHWAYS OF INTRODUCTION
DATA SOURCE SCALE OF
COVERAGE DESCRIPTION
LEVEL OF
CONFIDENCE BASED
ON COMPLETENESS
AND ACCURACY
INDICATOR INFORMED
BY THESE DATA
Plisko (2010)* Na ional His o ical in oduc ion da a o Annelida Medium 2. In oduc ion a es
Richa dson e al. (2003) Na ional Socio-economic in o ma ion on
ho icul u e. In o ma ion on he sp ead
o i sh species
High 1. In oduc ion pa hway
p ominence
4. Wi hin-coun y
dispe sal a es
Seebens e al. (2017) Global In o ma ion on global ends in he
in oduc ion o alien species
Medium 1. In oduc ion pa hway
p ominence
2. In oduc ion a es
Sou h A ican
Go e nmen (2017)
Na ional Socio-economic in o ma ion on i shing Medium 1. In oduc ion pa hway
p ominence
S a sSA ou ism and
mig a ion s a is ics
(S a is ics Sou h A ica,
2017)
Na ional Socio-economic in o ma ion on he
numbe o people a i ing in Sou h
A ica
Medium 1. In oduc ion pa hway
p ominence
Taylo , Lindsay &
Da ies-Mos e (2015)
Na ional Socio-economic in o ma ion on he
hun ing sec o
Medium 1. In oduc ion pa hway
p ominence
3. Wi hin-coun y
pa hway p ominence
T ansne Na ional Po s
Au ho i y (2014)
Na ional Socio-economic in o ma ion on
shipping
Medium 1. In oduc ion pa hway
p ominence
T ansne Na ional Po s
Au ho i y’s Po s a is ics
(T ansne Na ional Po s
Au ho i y, 2017)
Na ional Socio-economic in o ma ion on
shipping
High 1. In oduc ion pa hway
p ominence
Uni ed Na ions Com ade
da abase (UN-Com ade,
2017)
Global Socio-economic da a on li e plan and
ehicle impo s
Medium 1. In oduc ion pa hway
p ominence
Van Rensbu g e al.
(2011)*
Na ional His o ical in oduc ion da a o
eshwa e i sh, amphibians, bi ds,
mammals and ep iles. In o ma ion on
he i shing, hun ing and aquacul u e
sec o s and he wi hin-coun y dispe sal
o i sh
Medium 1. In oduc ion pa hway
p ominence
2. In oduc ion a es
3. Wi hin-coun y
pa hway p ominence
4. Wi hin-coun y
dispe sal a es
Van Wilgen e al. (2010) Na ional Socio-economic in o ma ion on he
impo o animals as pe s
Medium 1. In oduc ion pa hway
p ominence
Visse e al. (2017a) Na ional In o ma ion on he in oduc ion o Tu a
absolu a o Sou h A ica
Medium 1. In oduc ion pa hway
p ominence
Visse e al. (2017b) Na ional In o ma ion on he cu en and his o ical
in oduc ion pa hways o g asses
Medium 1. In oduc ion pa hway
p ominence
WTO ade s a is ics
(Wo ld T ade
O ganisa ion, 2017)
Global Socio-economic in o ma ion on
me chandise impo s
Medium 1. In oduc ion pa hway
p ominence
WTTC’s ou ism and a el
s a is ics (Wo ld Tou ism
and T a el Council, 2017)
Global Socio-economic in o ma ion on a el
and ou ism
Medium 1. In oduc ion pa hway
p ominence
Zacha iades e al. (2017) Na ional In o ma ion on biological con ol agen s
eleased o con ol alien plan s and
u u e plans o hese p og ams
High 1. In oduc ion pa hway
p ominence
4. Wi hin-coun y
dispe sal a es
Zimme mann, Mo an &
Ho mann (2004)
Na ional In o ma ion on biological con ol agen s
and hei wi hin-coun y dispe sal
High 4. Wi hin-coun y
dispe sal a es
34
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
3.3. STATUS OF THE PATHWAYS
3.3.1. S a us o he pa hways o in oduc ion
Based on socio-economic da a, many o he pa hways o in oduc ion appea o be playing an impo an ole in
Sou h A ica and in many cases he p ominence o hese pa hways has inc eased o e ime (see Figu e 3.1 and
Table A2.1). The e a e 72 o i cial po s o en y h ough which people, goods and anspo essels can en e he
Republic. Eigh o hese a e ma i ime po s, en a e ai po s and 54 a e land bo de pos s (Figu e 3.2). The numbe
o people en e ing Sou h A ica h ough hese po s o en y has inc eased o e ime, and in 2016 o e 21 million
people en e ed he coun y (Figu e 3.3). Acco ding o he Wo ld Tou ism and T a el Council (2017), o e 10
million o hese we e ou is s. Tou ism and a el is an impo an indus y in Sou h A ica and he con ibu ion
his sec o has made o G oss Domes ic P oduc (GDP) has inc eased o e ime (Figu e 3.4). The quan i y o ood
impo ed in o Sou h A ica h ough he po s o en y has also inc eased o e ime, and in 2013 o e 7 million
onnes o ood was impo ed (Figu e 3.5). These pa hways a e examples o many ha a e playing a majo and
inc easing ole in Sou h A ica, and as alien axa could be anspo ed in o he coun y wi hin he luggage o
ou is s, o as con aminan s o impo ed ood, hese pa hways, along wi h a numbe o o he s, migh be playing
an impo an and inc easing ole in he in oduc ion o alien o ganisms.
FIGURE 3.2 Sou h A ican po s o en y. Any pe son, who wishes o en e in o o depa om Sou h A ica, can only legally do
so h ough hese po s. In o ma ion was ob ained om he Sou h A ican D epa men o Home A ai s (2017).

35
CHAPTER 3
I
PATHWAYS OF INTRODUCTION
AIR TRANSPORT
Yea
20162006
0
1
2
3
4
5
6
Numbe o a i als
(millions)
ROAD TRANSPORT
Numbe o a i als
(millions)
Yea
20162006
0
2
4
6
8
10
12
14
16
18
SEA TRANSPORT
Numbe o a i als
Yea
20162006
0
10 000
20 000
30 000
40 000
50 000
60 000
70 000
FIGURE 3.3 The numbe people a i ing in Sou h A ica by ai , oad and sea anspo in 2006 and 2016. Da a we e ob ained
om S a is ics Sou h A ica (2017).
2009
2011
2013
2015
2017
2019
2021
2023
2025
2027
2007
Yea
45
Con ibu ion o GDP
(billions o US dolla s a eal p ices)
40
35
30
25
20
15
10
5
0
1995
1997
1999
2001
2003
2005
FIGURE 3.4 The con ibu ion o a el and ou ism o Sou h A ica’s G oss Domes ic P oduc has inc eased o e ime and is
expec ed o con inue o inc ease in he u u e. Da a we e ob ained om he Wo ld Tou ism and T a el Council (2017).
Yea
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2011
2013
2005
2007
2009
Quan i y o impo ed ood
(million onnes)
7
8
6
5
4
3
2
1
0
FIGURE 3.5 The quan i y o ood impo ed in o Sou h A ica has inc eased, pa icula ly since 2000. Da a we e ob ained om he
Food and Ag icul u al O ganisa ion o he Uni ed Na ions (FAO , 2017).
36
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
As many in oduc ion pa hways a e p ominen in Sou h A ica, i is no su p ising ha alien axa ha e been in en ionally and
acciden ally in oduced o he coun y h ough a wide a ie y o in oduc ion pa hways. Al hough mos alien axa ha e been
in en ionally impo ed o he o namen al plan ade and hen ha e escaped om ga dens (Figu e 3.1, Figu e 3.6 and Figu e
3.7), many ha e also been eleased o biological con ol o ha e been in oduced o ag icul u e (Figu e 3.1 and Figu e 3.7).
Al hough mos alien axa ha e been in en ionally impo ed in o he coun y, a la ge numbe ha e also en e ed he coun y
acciden ally (Figu e 3.6). Fo example, many alien axa ha e been in oduced as con aminan s on impo ed plan s, o as
s owaways on isi ing ships (Figu e 3.1 and Figu e 3.7). O ganisms ha ha e been in oduced o Sou h A ica’s neighbou ing
coun ies ha e also sp ead in o he coun y; howe e , no alien axa a e known o ha e sp ead in o Sou h A ica h ough
human-buil anspo in as uc u e ha connec s p e iously unconnec ed egions (Figu e 3.1 and Figu e 3.6).
Pa hway o in oduc ion
Release in na u e Escape om Con i nemen T anspo – Con aminan T anspo – S owaway Co ido Unaided Unknown
0
500
1000
1500
Numbe o in oduced axa
FIGURE 3.6 Numbe o alien axa in oduced o Sou h A ica h ough he pa hways o in oduc ion ( ollowing he ca ego isa ion scheme
adop ed by he Con en ion on Biological Di e si y), and he numbe o axa o which pa hway o in oduc ion was unknown.
RELEASE IN NATURE
Numbe o
in oduced axa
Biological con ol E osion con ol/
dune s abilisa ion
Fishe y in he wild Hun ing Landscape/ l o a/
auna imp o emen
Conse a ion
pu poses o wildli e
managemen
Release in
na u e o use
O he in en ional
elease
No enough de ail
0
100
200
ESCAPE FROM CONFINEMENT
Numbe o
in oduced axa
Ag icul u e Aquacul u e/
ma icul u e
Bo anical
ga den/zoo/
aqua ia
Pe /aqua ium/
e a ium
species
Fa med
animals
Fo es y Fu a ms Ho icul u e O namen al
pu pose o he
han ho icul u e
Resea ch
(in acili ies)
Li e ood and
li e bai s
O he
escape om
con i nemen
No enough
de ail
0
100
200
TRANSPORT – CONTAMINANT
Numbe o
in oduced axa
Con aminan
nu se y ma e ial
Con amina ed
bai
Food
con aminan
Con aminan
on animals
Pa asi es
on animals
Con aminan
on plan s
Pa asi es
on plan s
Seed
con aminan
Timbe ade T anspo a ion
o habi a
No enough
de ail
0
100
200
TRANSPORT – STOWAWAY
Numbe o
in oduced axa
Angling/Fishing
equipmen
Con aine /bulk Hi chhike s in
o on ai plane
Hi chhike s on
ship/boa
Machine y/
equipmen
People and
hei luggage
O ganic packing
ma e ial
Ship/boa
ballas wa e
Ship/boa hull
ouling
Vehicles O he means
o anspo
No enough
de ail
0
100
200
Pa hway o in oduc ion
FIGURE 3.7 Numbe o alien axa in oduced o Sou h A ica h ough he pa hways o in oduc ion, and he numbe o which designa ion
a he pa hway subca ego y le el was no possible due o insu i cien in o ma ion. The g aphs show he esul s o he pa hway subca ego ies o
he ( om op o bo om) ‘Release in na u e’, ‘Escape om con i nemen ’, ‘T anspo – Con aminan ’ and ‘T anspo – S owaway’ pa hway
ca ego ies. Resul s o he unaided pa hway a e no shown (see Figu e 3.6 o he esul s o his pa hway).
37
CHAPTER 3
I
PATHWAYS OF INTRODUCTION
Al hough da a we e insu i cien o many o he pa hways o in oduc ion, o some pa hways da a we e su i cien
o e alua e ecen changes o he a e o in oduc ion, and o assess he e ec i eness o con ol measu es. Fo
ele en pa hways, be ween 2000 and 2009 he e was ei he a minimal change o an inc ease o he a e o
in oduc ion in compa ison o ha o he p e ious decade (Figu e 3.1). The e o e, al hough con ol measu es
we e enac ed o some pa hways in he 1980s, o many pa hways he a e o in oduc ion has no declined
(Figu e 3.1, also see Box 3.1 o an example). The a e a which alien axa ha e been in oduced o Sou h A ica
has declined o only one pa hway: biological con ol (Figu e 3.1). Regula o y p ocess complica ions caused a
decline in he numbe o axa in oduced o he biological con ol o in asi e plan s (Klein , 2011; Klein e al.,
2011), while he numbe o insec s eleased o con ol insec pes s has also declined since he 1980s (Cock e al.,
2016). O e all he in oduc ion o biological con ol agen s was, he e o e, lowe in he 1990s and 2000s han in
he 1980s (see Figu e A2.4). As he complica ions in hese egula o y p ocesses ha e since been esol ed, and as
biological con ol esea ch and implemen a ion o alien plan s has ecen ly inc eased (Zacha iades e al., 2017),
i is likely he e will be an inc ease in he elease o biological con ol agen s in he u u e (Figu e 3.1). The e ha e
been no new alien axa in oduced o i shing o aquacul u e since he 1980s (Figu e 3.1; also see Figu e A2.4 and
Figu e A2.5). While his d ecline migh be due o he con ol measu es ha we e implemen ed du ing his pe iod
[i.e. Animal Diseases Ac (Ac No. 35 o 1984)], changing ashions o o he socio-economic ac o s could also
ha e played a ole. Du ing he las ull decade (2000–2009), he annual a e o in oduc ion has l uc ua ed, wi h
an a e age o 7 axa in oduced pe yea (Figu e 3.8). O e all, and despi e he con ol measu es ha a e in place,
he a e o in oduc ion appea s o be inc easing (Figu e 3.9).
Yea
Numbe o axa
in oduced pe yea
2005 2006 2007 2008 2009200420012000
0
5
10
15
2002 2003
FIGURE 3.8 The numbe o axa in oduced o Sou h A ica du ing each yea in he las ull decade.
38
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
Numbe o in oduced axa
Time pe iod
0
20
40
60
80
100
1950-19591960-1969 1970-1979 1980-1989 1990-1999 2000-2009 2010-2019
FIGURE 3.9 The numbe o axa in oduced o Sou h A ica du ing each decade since he 1950s. Da a o 2010 o 2019 we e
incomple e and a e shaded in g ey.
3.3.2. S a us o he pa hways o dispe sal
Wi hin-coun y pa hway p ominence is cu en ly no known o all pa hways o dispe sal, in pa as da a a e widely
dispe sed and owned by a numbe o di e en en i ies. Sou h A ica, howe e , has ex ensi e anspo ne wo ks
(Figu e 3.10) ha acili a e he mo emen o goods and people a ound he coun y. In line wi h in e na ional
ade pa e ns, he olume o goods and he numbe o people mo ing a ound he coun y is expec ed o
inc ease. Fo ins ance, he numbe o domes ic ai line passenge s has inc eased o e ime – such ha in he
2015/2016 i nancial yea , he e we e o e 13 million ips made on o e 140000 l igh s (Figu e 3.11).
Impo an ly, no all o he species mo ing wi hin he coun y a e alien o he Republic, and species ha a e
indigenous o one pa o he coun y can also be anspo ed and in oduced o pa s o he coun y whe e hey
a e no indigenous (Measey e al., 2017). Alien and indigenous species ha a e sold a pe s o es (Figu e 3.12) a e
o en aded (e.g. h ough p i a e o public sales on web-si es like Ebay) and mo ed a ound he coun y by
membe s o he public (Ma in & Coe zee, 2011, Measey e al., 2017). Simila ly alien and indigenous i sh a e o en
anspo ed and in oduced in o new i e sys ems by angle s (Picke & G i i hs, 2011). Many alien axa ha e also
become widely dispe sed h ough na u al sp ead [e.g. S u nus ulga is ( he common s a ling) was in oduced o
he Wes e n Cape and sp ead no h (Picke & G i i hs, 2011)], bu alien o ganisms a e also anspo ed as
con aminan s o commodi ies o as s owaways along he coun y’s ex ensi e anspo ne wo ks (Figu e 3.10).
Fo example, Si ex noc ilio (si ex woodwasp) was p obably impo ed and anspo ed a ound he coun y in
in es ed imbe (Picke & G i i hs, 2011; Hu ley e al., 2012). O ganisms a e also known o ha e sp ead wi hin he
coun y h ough human made anspo in as uc u e ha connec s p e iously unconnec ed a eas. Fo example,
i sh species ha e dispe sed along canals and pipes used o ans e wa e be ween i e basins (Richa ds on e al.,
2003; Van Rensbu g e al., 2011).
45
CHAPTER 3
I
PATHWAYS OF INTRODUCTION
INDICATOR VALUE
BASIC ADVANCED
LEVEL OF
CONFIDENCE NOTES
2. In oduc ion a es 2.1.
0 axa:
10 pa hways
1 – 50 axa:
27 pa hways
51 – 100 axa:
5 pa hways
> 100 axa:
2 pa hways
2.2.
Inc ease:
2 pa hways
Dec ease:
1 pa hway
Minimal change:
9 pa hways
No in oduc ions:
18 pa hways
No known:
14 pa hways
2.3. Da a no
a ailable
2.1. Low
2.2. Low
Pa hway and da e
o in oduc ion da a
a e no a ailable o
ha e no been
colla ed o many
alien axa in Sou h
A ica
3. Wi hin-coun y
pa hway
p ominence
3.1. Da a no
a ailable
3.2. Da a no
a ailable
3.3. Da a no
a ailable
N/A Da a we e only
collec ed o a ew
pa hways
4. Wi hin-coun y
dispe sal a es
4.1. Da a no
a ailable
4.2. Da a no
a ailable
4.3. Da a no
a ailable
N/A Pa hway and da e
o dispe sal da a
ha e no been
colla ed o alien
axa in Sou h A ica
A. Ra e o
in oduc ion o
new un egula ed
species
A. 7 axa pe yea A. Low Da e o in oduc ion
da a a e no a ailable
o many alien axa in
Sou h A ica
BOX 3.1 THE LIVE PLANT TRADE AS A PATHWAY FOR INTRODUCING CONTAMINANTS.
Li e plan s and hei p oduc s a e impo ed in o Sou h A ica o a numbe o uses. Fo example, as Sou h
A ican consume s in he o namen al plan sec o show a desi e o new a ie ies o plan s, plan s a e o en
impo ed o his pu pose (Middle on, 2015). Li e plan impo s o Sou h A ica ha e inc eased o e ime and
in 2016 hese impo s we e alued a o e 12million US dolla s (UN-Com ade, 2017). To mee he
equi emen s o he In e na ional Plan P o ec ion Con en ion, Sou h A ican phy osani a y policies equi e
ha all plan impo s mus be inspec ed in he coun y o o igin, ea ed wi h pes icides and decla ed ee o
any o ganisms be o e impo (Saccaggi & Pie e se, 2013). Despi e his, o ganisms a e o en ound on impo ed
plan s and plan p oduc s when inspec ed a Sou h A ican po s o en y (Saccaggi & Pie e se, 2013).
Addi ionally, o e 20 species ha e been in oduced as con aminan s o pa asi es o plan s, and he a e a
which hese o ganisms ha e been in oduced has emained consis en o e ime (Figu e 3.1; also see Table
A2.1). Fo example, Linepi hema humile (A gen ine an ) is belie ed o ha e been in oduced o Sou h A ica as
a con aminan o impo ed ho se odde (Picke & G i i hs, 2011). Once impo ed, plan s a e in en ionally
anspo ed and sold h oughou he coun y (Ma in & Coe zee, 2011), and hei con aminan s a e
po en ially anspo ed wi h hem. The li e plan ade is, he e o e, an impo an and po en ially inc easing
pa hway h ough which alien o ganisms a e in oduced o he coun y, bu his ade also likely acili a es he
dispe sal o alien axa wi hin he coun y a e in oduc ion.

46
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
BOX 3.2 HULL FOULING AS A PATHWAY OF INTRODUCTION FOR MARINE ORGANISMS.
Pho og aphe : T. Robinson
Sou h A ica has eigh majo ma i ime po s (Richa ds Bay, Du ban,
Eas London, Ngqu a, Po Elizabe h, Mossel Bay, Cape Town and
Saldanha Bay), and in 2016 o e 8000 ocean going essels a i ed
a hese po s (T ansne Na ional Po s Au ho i y, 2017). Ships can
acili a e he in oduc ion o alien axa in a numbe o ways. Ma ine
o ganisms can be anspo ed wi hin he ballas wa e ca ied by
ships o can a ach o ships’ hulls. Th ough hese pa hways ships
ha e acili a ed he in oduc ion o many ma ine axa o Sou h
A ica (Figu e 3.1). In Sep embe 2017, he In e na ional Ma i ime
O ganisa ion’s (IMO) ‘In e na ional Con en ion o he Con ol and
Managemen o Ships’ Ballas Wa e and Sedimen s’ en e ed in o
o ce (IMO, 2004). This con en ion aims o p e en he
anspo a ion o aqua ic o ganisms be ween egions, and unde
he con en ion all ships a e equi ed o manage hei ballas wa e
and sedimen s o a ce ain s anda d. Sou h A ica has also d a ed
ballas wa e legisla ion (Ma ine D a Ballas Wa e Bill), bu his
legisla ion has no ye been passed. Al hough he e a e, he e o e,
plans o manage he in oduc ion o ma ine o ganisms h ough he
elease o ballas wa e by ships, he e a e cu en ly no plans o
managemen in place o p e en in oduc ions h ough hull ouling. O e 60 alien axa a e belie ed o ha e
been in oduced o Sou h A ica a ached o he hulls o isi ing ships, and he a e a which hese
in oduc ions ha e occu ed has inc eased o e ime (Figu e 3.1; also see Table A2.1). Fu he mo e, o deal wi h
inc easing demand, all o Sou h A ica’s majo po s, excep Mossel Bay, will be upg aded and expanded in he
u u e (T ansne Na ional Po s Au ho i y, 2014). This ac ion could lead o an inc ease in he numbe o isi ing
ships, and unless addi ional biosecu i y measu es a e pu in place, he inc eased shipping in ensi y could esul
in an inc ease in he in oduc ion o ma ine o ganisms h ough hull ouling. The h ea posed by his pa hway
is, howe e , no simply in p opo ion o he numbe o isi ing ships, and is highe o pa icula po s (Du ban
in pa icula ) and o pa icula ade ou es ( ou es om Asia) (Faulkne e al., 2017b).
4
THE STATUS OF
ALIEN SPECIES
Lead au ho s:
B ian an Wilgen,
Tendamudzimu Munyai,
Zanele Mnika hi,
John Wilson
Con ibu ing au ho s:
Tumelo Mo api,
Lee-Anne Bo ha,
The ese Fo sy h,
Dai He be ,
Ian Rushwo h,
Llewellyn Foxc o ,
Hea he Te apon,
And ew Tu ne ,
Rob Li le,
Michelle G e e,
John Measey,
Tammy Robinson,
Cha les G i i hs,
Pa Holmes,
Siyasanga Miza
Chap e summa y
This chap e p o ides an o e iew o he s a us o alien species in Sou h A ica
based on da a om a wide ange o sou ces (a las p ojec s, expe assessmen s,
lis s, and published pape s and epo s).
O he 2033 alien species eco ded (o assumed o be p esen ) ou side o
cul i a ion o cap i i y in Sou h A ica, 775 a e known o be in asi e, 388 a e
known o be na u alised bu no in asi e, and 355 a e p esen , bu no
na u alised. Fo he emainde (516 species), he e is insu i cien in o ma ion o
assign hem o an in oduc ion s a us ca ego y. Eigh o he alien species
eco ded as p esen in he coun y a e cu en ly lis ed in he NEM:BA egula ions
as p ohibi ed (i.e. species assumed o be absen om Sou h A ica and which
may no be impo ed).
La ge numbe s o alien species ha e ela i ely es ic ed dis ibu ions. Only in
he case o plan s and bi ds a e he e widesp ead species [e.g. ound in a leas
a qua e (i.e. > 500) o he qua e -deg ee g id cells (QDGCs) o Sou h A ica].
A leas one alien ep ile and wo e es ial in e eb a e species a e ela i ely
widesp ead (> 100 QDGCs), al hough he da a co e age is poo , so he e is a
low le el o con i dence in hese es ima es.
The only da a a ailable o es ima e he abundance o alien species a e hose o
e es ial and eshwa e plan s. These es ima es a e e y c ude o o e 20 yea s
ou o da e, so he le el o con i dence in hese es ima es is e y low. The e a e
no compa able da a o any o he high-le el axa.
A sys ema ic e alua ion o he impac s o indi idual in asi e species as pe he
ecen ly de eloped in e na ional s anda ds has no ye been conduc ed.
Howe e , 25 species we e assessed by expe s as ha ing a se e e impac , and
82 as ha ing a majo impac . O hese 107 species, mos (80) a e e es ial o
eshwa e plan s, eigh a e mammals, i e each a e eshwa e i sh, eshwa e
in e eb a es and e es ial in e eb a es, wo a e amphibians, and he e is one
bi d and one ma ine plan species.
Alien plan s a e he mos di e se, widesp ead and damaging g oup o in ade s in
Sou h A ica. Fu he mo e, i is clea ha Sou h A ica has a majo alien plan
in asion deb . Well o e 100 new axa ha e been eco ded as na u alised o
escapes om cul i a ion o e he pas decade, and he eco ded ange o almos
all plan s has inc eased signi i can ly. This is a signi i can cause o conce n, as i
clea ly indica es ha p oblems associa ed wi h alien species a e se o inc ease.
Teph ocac us a icula es (pine cone cac us) – SANBI
48
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
4.1. INTRODUCTION
This chap e p o ides an o e iew o he numbe s, ex en , abundance and
impac o alien species in Sou h A ica. The numbe o species was es ima ed
using he lis in he NEM:BA A&IS Regula ions as a s a ing poin , and adding
o he (unlis ed) species ha ha e been epo ed as na u alised in Sou h A ica.
The ele an indica o s a e he Numbe and s a us o alien species (i.e. whe he
hey a e known o be p esen in Sou h A ica and hei s age o in oduc ion); he
Ex en o alien species (a na ional, p o incial, biome o o he scales); he Abundance
o alien species s a us (in e ms o hei co e , biomass o popula ion sizes); and
he Impac o alien species ( he deg ee o which he species has nega i e impac s).
See Table 2.3 o u he de ails.
Da a we e ob ained om a a ie y o sou ces (Table 4.1). These da a we e o
a ying quali y, and his a ec ed he le el o con i dence placed in each indica o .
In addi ion, he a ailable da a co e ed some, bu no all, o he in o ma ion
needed o assign alues o indica o s, and o some indica o s i is no ye possible
o assign alues due o a lack o da a (Table 4.2).
TABLE 4.1 Sou ces o da a used o assign alues o species indica o s, wi h le els o con i dence based on he comple eness and
accu acy o da a se s. Sou ce Ins i u ions o da a: Animal Demog aphy Uni (ADU); Cen e o In asion Biology (C•I•B ); KwaZulu-Na al
Museum (KZN Museum); Plan P o ec ion Resea ch Ins i u e o he Ag icul u al Resea ch Council (ARC-PPRI); Sou h A ican Ins i u e
o Aqua ic Biodi e si y (SAIAB); Sou h A ican Na ional Biodi e si y Ins i u e (SANBI); Sou h A ican Na ional Pa ks (SANPa ks);
S ellenbosch Uni e si y (SU); Uni e si y o Cape Town (UCT); Uni e si y o KwaZulu-Na al (UKZN); Uni e si y o P e o ia (UP). The
numbe ing o indica o s is based on Chap e 2: 5. Numbe and s a us o alien species; 6. Ex en o alien species; 7. Abundance o alien
species; 8. Impac o alien species.
TAXON SOURCE (SEE
FOOTNOTE*)
TOTAL NUMBER OF
SPECIES DESCRIPTION
LEVEL OF
CONFIDENCE BASED
ON COMPLETENESS
AND ACCURACY
INDICATOR
INFORMED
BY THESE
DATA
All Cape Na u e To als p o ided o
indi idual
p o ec ed a eas; no
es ima e o
numbe s ac oss all
p o ec ed a eas
Lis s main ained o
indi idual p o ec ed a eas
Mode a e o low,
depending on he
p o ec ed a ea. Some
p o ec ed a eas ha e
been poo ly su eyed
5
All D Llewellyn
Foxc o , (C•I•B/
SANPa ks);
Foxc o e al.
(2017)*
869 Lis s main ained by
SANPa ks
High o low,
depending on he
pa k. Some a e
well-su eyed, o he s
a e da a-poo
5, 6
All D Michelle G e e
(UP)
47 Da abase o alien species
occu ing on he P ince
Edwa d Islands.
Mode a e -
conse a i e
es ima es as he
in asion s a us o
o he alien species is
unknown
5, 6, 8
All Ezem elo KZN
Wildli e
To als pe p o ec ed
a ea; no es ima e o
o al ac oss all
p o ec ed a eas
Lis s main ained o
indi idual p o ec ed a eas
Mode a e o low,
depending on he
p o ec ed a ea. Some
p o ec ed a eas ha e
been poo ly su eyed
5
species ha e majo impac s
acco ding o expe s
107
mos
(80)
a e e es ial o
eshwa e plan s
8
a e
mammals
1
ma ine
in e eb a e
5
each a e eshwa e i sh,
eshwa e in e eb a es
& e es ial in e eb a es
1
is a bi d
species
2
a e
amphibians
THE
SITUATION
49
CHAPTER 4
I
THE STATUS OF ALIEN SPECIES
TAXON SOURCE (SEE
FOOTNOTE*)
TOTAL NUMBER OF
SPECIES DESCRIPTION
LEVEL OF
CONFIDENCE BASED
ON COMPLETENESS
AND ACCURACY
INDICATOR
INFORMED
BY THESE
DATA
All NEM:BA A&IS
species lis
556 axa a e lis ed,
bu he numbe o
species is la ge as
he egula ions
some imes include
gene a wi h se e al
species.
Alien plan and animal
species lis ed as in asi e in
he NEM:BA A&IS
Regula ions, o p ohibi ed
species ound o be p esen
in Sou h A ica.
Mode a e – many
lis ed species a e no
assigned o he
co ec ca ego ies,
a e no in asi e, o
ha e no been
ecen ly eco ded in
Sou h A ica
5
All Zengeya e al.
(2017)*
552 A simple sco ing sys em
was used o classi y he
alien species acco ding o
he ela i e deg ee o hei
bene i s and nega i e
impac s.
Low 8
Amphibians;
Rep iles
Di song Na ional
Museum o Na u al
His o y Collec ion
(Manamela, 2016)
49 Di song Na ional Museum o
Na u al His o y Collec ion
con aining He pe ology,
Mammal and Bi d eco ds
om 1805 o 2008
Low – based on
poin da a and does
no include absence
eco ds
5, 6
Amphibians;
Rep iles
D John Measey
(C•I•B, SU);
Kumschick e al.
(2017); Measey e
al. (2017); Ba es e
al. (2014); Min e e
al. (2004)
44 Spa ial da abase (F og and
ep ile a lases) housed a
he ADU, UCT
High o amphibians
Mode a e o ep iles
5, 6, 8
Animals Picke & G i i hs
(2017)*
571 Comp ehensi e lis ing o
alien animal species in
Sou h A ica
Low 5, 6
Bi ds D Rob Li le (ADU/
UCT)
49 Spa ial da abase (Bi d a las)
housed a he ADU, UCT
High – moni o ing o
dis ibu ion is
equen and he
co e age is ex ensi e
5, 6
Bi ds; Te es ial
in e eb a es
Faulkne e al.
(2017a)*
274 Desc ip ion o how alien
species migh ha e been
in oduced o he egion
and sp ead be ween Sou h
A ica and elsewhe e in
A ica
Mode a e 5, 6
F eshwa e i sh Ma e al. (2017)* 27 F eshwa e i sh species
in oduced in o he wa e
cou ses o Sou h A ica
Mode a e 5, 8
F eshwa e i sh SAIAB Few Assessmen s o species-
speci i c impac s published in
he scien i i c li e a u e, and in
heses
Low – e y ew
species ha e been
adequa ely s udied
8
F eshwa e
in e eb a es
Albany Museum
(De Moo , 2015).
3Specimen eco ds held in he
Na ional Collec ion o
F eshwa e In e eb a es
housed in he Albany
Museum, G ahams own,
Sou h A ica. 60344 eco ds
wi h app oxima ely 57000
eco ds geo e e enced
Low, occu ence is
based on he gene a
and no species
5
50
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
TAXON SOURCE (SEE
FOOTNOTE*)
TOTAL NUMBER OF
SPECIES DESCRIPTION
LEVEL OF
CONFIDENCE BASED
ON COMPLETENESS
AND ACCURACY
INDICATOR
INFORMED
BY THESE
DATA
F eshwa e
in e eb a es;
Te es ial
in e eb a es
Global Biodi e si y
In o ma ion Facili y
(www.gbi .o g)
1017 Occu ence da a o
in e eb a es
Mode a e – Da a
consis en ly upda ed
on a egula bases
5, 6
F eshwa e
plan s
Hill & Coe zee
(2017)*
8 A e iew o he cu en
s a us o aqua ic weeds in
Sou h A ica, hei
socio-economic and
en i onmen al impac s and
he bene i s o hei con ol
Mode a e 5, 6, 8
Fungi; Te es ial
in e eb a es
Zacha iades e al.
(2017)*; Klein
(2011)
95 Assessmen o he s a us o
biological con ol as a
managemen ool o
supp ession o in asi e
alien plan s in Sou h A ica;
and a published e iew o
biological con ol agen s
High 5
Ma ine
in e eb a es
Iziko SA Museum:
Ma ine in e eb a e
collec ion
20 The collec ion comp ises
~130000 lo s o specimens
(including un-accessioned
ma e ial). Ele en hand-
w i en ca alogues exis o
ma ine in e eb a es da ing
back o 1871 and includes
76184 en ies
Low – da abase
includes un-
accessioned eco ds
5, 6
Ma ine
in e eb a es;
Ma ine plan s
D Tammy B.
Robinson (C•I•B/SU);
P o . Cha les L.
G iffi hs (C•I•B/UCT);
Ms S. Miza (SANBI)
93 Lis p o ided by expe s Low – based only on
p elimina y su eys
and many species
p obably emain
undisco e ed o
un ecognised as alien
5, 6, 8
Mic obial species Wood (2017)* 112 P elimina y lis ing o alien
ungal species
Ve y low 5
Rep iles Sou he n A ican
Rep ile
Conse a ion
Assessmen (SARCA,
Na a o 2015)
4 Dis ibu ion eco ds o he
ep iles o sou he n A ica,
om li e a u e and he
SARCA Vi ual Museum
Low – ew eco ds o
alien ep iles we e
included in he
assessmen
5, 6
Soil bio a Janion-Scheepe s
e al. (2016)
103 Recen ly published e iew
o soil bio a
Low 5, 6
Te es ial and
eshwa e
plan s
Bews He ba ium
(UKZN)
168 Da abase o well-iden i i ed
and ai ly ex ensi e in asi e
alien and p oblem plan
collec ion o he Bews
He ba ium, UKZN
High – based on
published da a
5, 6
Te es ial and
eshwa e
plan s
Bo anical Da abase
o Sou he n A ica,
BODATSA
(Ranwashe, 2015)
401 BODATSA is a da abase ha
con ains he o i cial plan
name da a eco ds. The
da a collec ed co e s
obse a ional da a, species
checklis s, specimen
in o ma ion, species
desc ip ion, li e a u e and
collec o in o ma ion om
i e he ba ia. This is o
main ain he mos cu en
scien i i cally accu a e
assessmen s o sou he n
A ican plan s
Mode a e – based on
egula ly upda ed
da a
5, 6

51
CHAPTER 4
I
THE STATUS OF ALIEN SPECIES
TAXON SOURCE (SEE
FOOTNOTE*)
TOTAL NUMBER OF
SPECIES DESCRIPTION
LEVEL OF
CONFIDENCE BASED
ON COMPLETENESS
AND ACCURACY
INDICATOR
INFORMED
BY THESE
DATA
Te es ial and
eshwa e
plan s
Sou he n A ican
Plan In ade s A las
(SAPIA); Hende son
& Wilson (2017)*.
773 A las main ained by he
PPRI-ARC
Mode a e – based on
oadside su eys o
a ying co e age
5, 6
Te es ial and
eshwa e
plan s (g asses)
Visse e al. (2017b)* 256 Re iew o g asses as
in asi e alien plan s in
Sou h A ica.
Mode a e 5, 8
Te es ial
in e eb a es
(insec s)
Albany Museum
(Gess, 2015)
72 Da abase o he e es ial
insec collec ions o he
Albany museum
Mode a e – based on
published da a,
howe e has no
been upda ed
6
Te es ial
in e eb a es
(insec s)
D Ruan Veld man
(SANBI)
9 Lis p o ided by expe Low 5
Te es ial
in e eb a es
(insec s)
Recen ly published
comp ehensi e
assessmen o insec
pes s on c ops and
pas u es in Sou h
A ica (P insloo &
Uys 2015)
107 P insloo & Uys (2015)
p o ided de ailed accoun s
o 693 insec pes s o
cul i a ed plan s and
pas u es in Sou h A ica; o
hese, 107 (14.6%) we e
alien species
Low – he ocus o
his da ase was on
pes s o ag icul u al
c ops and pas u es
only. Alien s a us o
species no explici ly
included
5
Te es ial
in e eb a es
(molluscs)
Da id Kesne (SU) 16 Assessmen s o impac s as
pa o an ongoing s udy
Mode a e 8
Te es ial
in e eb a es
(molluscs)
P o Dai He be
(KZN Museum)
39 Da abase and specimens
cu a ed by he KZN
Museum
Low – eco ds a e
accu a e, bu
sampling in ensi y is
low
5, 6, 8
Te es ial plan s Clusella-T ullas &
Ga cia (2017) *
15 Impac s o in asi e alien
plan s on abundance,
ichness and composi ion o
se e al axonomic g oups o
ec o he ms
Low 8
Te es ial plan s
(cac i)
Kaplan e al. (2017)* 31 An assessmen o he s a us
o cac us in asions in Sou h
A ica.
Mode a e 5, 6
* Pape s we e pa o he jou nal special issue ha was p oduced as pa o he s a us epo p ocess, see Box 1.3.
52
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
TABLE 4.2 Es ima ed comple eness and accu acy o da a equi ed o assign alues o alien species indica o s in Sou h A ica o
di e en axonomic g oups. The axonomic g oupings a e as pe he NEM:BA A&IS Regula ions. Le els o comple eness a e: High
(in o ma ion a ailable o > 75% o species); Mode a e (in o ma ion a ailable o 30–75% o species); Low (in o ma ion a ailable o
< 30% o species). Le els o accu acy e e o a ailable da a, as ollows: High (poin dis ibu ion da a a ailable, o ecology and
impac s well-documen ed); Mode a e (qua e -deg ee g id cell dis ibu ion da a a ailable o supe i cial s udies a ailable on ecology
and impac s); Low (no o mal mapping o documen ed s udies on ecology and impac s). N/A is no applicable.
INDICATOR TAXON COMPLETENESS ACCURACY
Numbe and s a us o
alien species
Amphibians High High
Bi ds High High
F eshwa e i sh High High
F eshwa e in e eb a es Low Low
Mammals High Mode a e
Ma ine i sh N/A N/A
Ma ine in e eb a es Low Low
Ma ine plan s Low Low
Mic obes Low Low
Rep iles Mode a e Mode a e
Te es ial and eshwa e plan s High Mode a e
Te es ial in e eb a es Low Low
Ex en o alien species Amphibians High Mode a e
Bi ds Mode a e Mode a e
F eshwa e i sh High Low
F eshwa e in e eb a es Low Low
Mammals Mode a e Mode a e
Ma ine i sh N/A N/A
Ma ine in e eb a es Low Low
Ma ine plan s Low Low
Mic obes Low Low
Rep iles High Mode a e
Te es ial and eshwa e plan s High Mode a e
Te es ial in e eb a es Low Low
Abundance o alien species Te es ial and eshwa e plan s Low Low
All o he axa No da a No da a
Impac o alien species Amphibians Mode a e Mode a e
Bi ds Low Low
F eshwa e i sh Low Low
F eshwa e in e eb a es Low Low
Mammals Low Low
Ma ine i sh Low Low
Ma ine in e eb a es Low Low
Ma ine plan s Low Low
Mic obes Low Low
Rep iles Mode a e Mode a e
Te es ial and eshwa e plan s Low Low
Te es ial in e eb a es Low Low
53
CHAPTER 4
I
THE STATUS OF ALIEN SPECIES
4.2. THE NUMBER AND STATUS OF ALIEN SPECIES IN SOUTH AFRICA
The in oduc ion s a us o alien species can be assessed a di e en le els, depending on he a ailabili y o da a
(Table 4.3). Fo many species i was only possible o ei he de e mine whe he o no i was p esen in Sou h
A ica, while o o he s i was possible o assess whe he he species was absen , in oduced bu no na u alised,
na u alised bu no in asi e, o in asi e. The e a e e y ew s udies on speci i c g oups ha p o ide da a a he
hi d and highes le el o esolu ion, i.e. a b eakdown o in oduc ion s a us acco ding o he uni i ed amewo k
o Blackbu n e al. (2011), as was done, o example, by Jacobs e al. (2017). Full de ails o all species a e p o ided
in Appendix 3.
TABLE 4.3 The ela ionship be ween he h ee le els o esolu ion ha can be used o desc ibe in oduc ion s a us. Species a e
placed as a along he in oduc ion-na u alisa ion-in asion con inuum as hey can be wi h he a ailable e idence (e.g. he e has o
be epo ed e idence ha a species is in asi e o i o be classed as such).
PRESENCE BASIC INTRODUCTION
STATUS
STATUS ADAPTED FROM THE UNIFIED FRAMEWORK
FOR BIOLOGICAL INVASIONS (BLACKBURN ET AL., 2011)
ABSENT No p esen A0 (Ne e in oduced beyond limi s o indigenous ange o he egion in
ques ion, i.e. Sou h A ica)
A1 (Has been in oduced beyond limi s o indigenous ange o Sou h A ica,
bu no longe p esen )
PRESENT In oduced bu no
na u alised
B1 (in cap i i y o qua an ine)
B2 (in cul i a ion bu no measu es in place o p e en escape)
B3 ( eleased ou side o cap i i y o cul i a ion)
C0 (some escape om cap i i y o cul i a ion, bu su i al limi ed)
C1 (escape and su i al ou side o cap i i y o cul i a ion, bu no ep oduc ion)
C2 (escape, su i al, and ep oduc ion ou side o cap i i y o cul i a ion, bu
no clea whe he he popula ion is sel -sus aining)
Na u alised bu no
in asi e
C3 (escape, su i al, and ep oduc ion ou side o cap i i y o cul i a ion;
popula ion sel -sus aining bu no sp eading)
In asi e D1 (escape, su i al, ep oduc ion and sp ead ou side o cap i i y o
cul i a ion; hough no e idence o ep oduc ion pos -dispe sal)
D2 (escape, su i al, ep oduc ion, sp ead, and subsequen ep oduc ion ou side
o cap i i y o cul i a ion; hough sp ead as ye limi ed o a ew locali ies)
E (in asi e a mul iple locali ies)
4.2.1. Numbe o alien species in Sou h A ica
A o al o 2033 alien species we e ound o be p esen in Sou h A ica (Table 4.4). All o he species lis ed as
p ohibi ed in he A&IS Regula ions we e assumed o be absen om Sou h A ica, excep o eigh p ohibi ed
species ha a e known o ha e been in oduced. These include one bi d, one ep ile, wo amphibians, one
mic obial species and h ee in e eb a es.
54
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
4.2.2. S a us o alien species in Sou h A ica
O he 2033 alien species eco ded (o assumed o be p esen ) ou side o cul i a ion
o cap i i y in Sou h A ica, 775 a e known o be in asi e, 388 a e known o be
na u alised bu no in asi e, and 355 a e p esen , bu no na u alised. The e a e a
u he 516 species whe e he e is insu i cien in o ma ion on which o assign hem
o one o he basic in oduc ion s a us ca ego ies. Fo e es ial and eshwa e
plan s, he assessmen elied hea ily on he SAPIA da ase [see Hende son & Wilson
(2017) o a ecen analysis o he da abase]. Unless explici ly s a ed elsewhe e, he
assump ions we e made ha all axa eco ded in SAPIA we e na u alised and all axa
in wo o mo e qua e deg ee g id cells (QDGCs) we e in asi e. This is no s ic ly
co ec , as o a species o be eco ded in SAPIA he e is no o mal assessmen o
na u alisa ion, o whe he a popula ion is in asi e o no , bu he assump ion will
hold o he majo i y o eco ds. Fo he o he axa, he de e mina ion o a species as
in asi e was based on expe opinion whe e a ailable, o he wise he species was no
classed as na u alised o in asi e ( eco ded as NA – No Assessed – in Appendix 3).
Abou one hi d o he alien species ound ou side o cap i i y o cul i a ion in Sou h A ica a e known o ha e
become in asi e in Sou h A ica. The p opo ion di e ed among axa, wi h e es ial, eshwa e and ma ine
plan s ha ing ela i ely high p opo ions (55 – 64%), while ep iles and mic obes had no known in asi e species
( hough in he case o mic obes his is undoub edly a classi i ca ion e o ). The p opo ion o all in oduced
species ( o example o a genus o amily) ha a e in asi e will be lowe han he abo e es ima es, because he
es ima es exp ess he p opo ion in e ms o species ha a e al eady p esen ou side o cap i i y o cul i a ion.
Reliable es ima es o he p opo ion o species wi hin a genus a e only a ailable o some gene a o plan s, whe e
he p opo ion o in oduced species ha becomes in asi e anges om 2% o 22%. A leas 36 species in he
genus Melaleuca (bo leb ushes) ha e been in oduced o Sou h A ica, and 10 o hese ha e na u alised,
including 5 (14%) ha a e in asi e (Jacobs e al. 2017). Mo e han 80 species o he genus Acacia (Aus alian
wa les) ha e been in oduced o Sou h A ica, and 18 (22%) ha e been eco ded as na u alised (Richa dson, Le
Roux & Wilson 2015). A leas 68 species o he genus Pinus (pine ees) ha e been in oduced o Sou h A ica,
whe e eigh species ha e become in asi e (12%), and a u he 26 species a e ega ded as po en ially in asi e
(Van Wilgen & Richa dson, 2012). Such analyses ha e he po en ial o in o m isk analyses by iden i ying high- isk
g oups (Diez, Hulme & Duncan 2012), bu should be mode a ed by an assessmen o whe he in oduced axa
had an oppo uni y o become in asi e o no (Moodley e al., 2014).
Facili y o mass- ea ing biological con ol agen s – Kim Wea e Facili y o mass- ea ing biological con ol agen s – Kim Wea e
THE
SITUATION
alien species ha e es ablished
popula ions ou side
o cul i a ion o
cap i i y in
Sou h A ica
2033
o
h
e
s
e
a
e
i
n
a
s
i
e
775
61
CHAPTER 4
I
THE STATUS OF ALIEN SPECIES
Pa henium hys e opho us ( amine weed):
This annual he b is indigenous o opical Ame ica, and has been
p esen in Sou h A ica o o e 100 yea s. I has howe e only
ecen ly begun o sp ead apidly, and i now occu s ex ensi ely
in no he n KwaZulu-Na al, Swaziland, and Mpumalanga. The
species causes se e e alle gic eac ions in many people who
come in o con ac wi h i , as well as in li es ock and wildli e. I
has he po en ial o subs an ially educe angeland condi ion. I
is placed in ca ego y 1(b) (mus be con olled). Se ious a emp s
o con ol his species ha e only ecen ly begun. Indica ions a e
ha mechanical con ol alone will no con ain his species, bu
biological con ol op ions a e being in es iga ed, and hey hold
he po en ial o educe sp ead a es and igou .
Pho og aph: SANBI. Map: L. Hende son
Lan ana cama a (lan ana):
This sh ub was o iginally in oduced in o Sou h A ica om
sou h and cen al Ame ica as a ga den o namen al. I has
ex ensi ely in aded he ela i ely humid pa s o Sou h A ica,
whe e i can o m dense hicke s and ans o m ecosys ems. The
species p esumably impac s nega i ely on biodi e si y and is
also poisonous. I is placed in ca ego y 1(b) (mus be con olled).
Much e o has been di ec ed owa ds biological con ol o his
species, whe e he le el o con ol has been assessed as
subs an ial.
Pho og aph: SANBI. Map: L. Hende son
Mic op e us dolomieu (small-mou h bass):
This species was impo ed om no h Ame ica o p o ide
eshwa e angling oppo uni ies. Angle s ha e in oduced he
species o se e al i e sys ems, pa icula ly in he Wes e n and
Eas e n Cape P o inces. I p eys on indigenous i shes and
in e eb a es and can change he s uc u e o eshwa e
species communi ies. I s egula ion is complex. I is placed in
ca ego y 1(b) (mus be con olled) in p o ec ed a eas, and in
ca ego y 2 o 3 in dams and i e s whe e i al eady occu s. Once
es ablished, con ol is no easible excep in small s eams o
dams whe e i may be possible o ex i pa e popula ions.
Pho og aph: R. Duane, U.S. Fish and Wildli e Se ice. Map: SAIAB.

62
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
Ac ido he es is is (common mynah):
This species was b ough o Du ban om Asia in 1888, om
whe e i has sp ead o mos o no heas Sou h A ica. I a ou s
u ban en i onmen s (whe e popula ions can each hund eds o
housands), bu p obably has negligible impac s on na u al and
u al habi a s. I is lis ed as ca ego y 3 (does no equi e con ol,
bu may no be mo ed o aded). La ge-scale con ol would
p obably be impossible, bu occasional emo al o isola ed
indi iduals has been ca ied ou , o example in Cape Town and
he K uge Na ional Pa k.
Pho og aph: R. Taylo . Map: ADU.
My ilus gallop o incialis (Medi e anean mussel):
This species was acciden ally in oduced om Eu ope o Sou h
A ica’s wes coas in abou 1979, almos ce ainly by shipping. I
sp ead apidly o Namibia, and mo e slowly o he Eas e n Cape.
I now domina es mos o he ocky sho es o he wes and
sou h coas s, whe e i o ms dense, mul i-laye ed beds ha
monopolise space on in e idal ocks. I can be bene i cial as a
ood sou ce o bo h humans and animals ( o example he
A ican oys e ca che , Haema opus os alegus). Lis ed as
ca ego y 2 (cul i a ion and ade allowed wi h a pe mi ). I s
con ol would p obably be impossible, gi en he wide ange,
p oli i c ep oduc i e habi s, and widely-dispe sing la ae.
Pho og aph: S. Miza. Map d awn om da a supplied by D T. Robinson.
4.4. ABUNDANCE OF ALIEN SPECIES
Two sou ces o da a we e a ailable o es ima e he Abundance o alien species, bo h ela ing o plan s. The i s is
con ained in he 1998 epo o he Wa e Resea ch Commission (Appendix 5 in Ve s eld, Le Mai e & Chapman
1998). These es ima es a e e y c ude and 20 yea s ou o da e, so he le el o con i dence in hese es ima es is
e y low. The e a e no compa able da a o any o he high-le el axa. The second is he Na ional Alien In asi e
Plan Su ey o he Ag icul u al Resea ch Council (Ko zé e al., 2010). This su ey has a ocus o hose species
a ge ed o con ol by he Wo king o Wa e p og amme (mainly ees and sh ubs), and i excludes a e y la ge
p opo ion o a id Sou h A ica. In addi ion, he me hodology on which his su ey is based has ne e been
adequa ely documen ed, and he e o e he e can only be a low deg ee o con i dence in he es ima es a his
s age. In addi ion, because o di e ences in me hodology and sampling co e age, he i ndings o Ve s eld, Le
Mai e & Chapman (1998) and he Na ional Alien In asi e Plan Su ey a e no compa able (Table 4.5).
63
CHAPTER 4
I
THE STATUS OF ALIEN SPECIES
TABLE 4.5 In asi e plan axa lis ed as he mos abundan in Sou h A ica in e ms o co e by Ve s eld, Le Mai e & Chapman
(1998), and by Ko zé e al. (2010). Species we e anked by condensed in aded a ea (mean % co e × a ea occupied). Condensed ha is
he equi alen a ea occupied a a canopy co e o 100% (i.e. 50% co e on 10 ha = 5 condensed ha). No e ha es ima es om Ko zé
e al. (2010) exclude almos all o he a id pa s o Sou h A ica.
TAXON
EXTENT ABUNDANCE ABUNDANCE
( o al in aded a ea in 1000s
o ha as es ima ed by Ve s eld,
Le Mai e & Chapman 1998)
(condensed in aded a ea in 1000s
o ha as es ima ed by Ve s eld,
Le Mai e & Chapman 1998)
(condensed in aded a ea in
1000s o ha as es ima ed
by Ko zé e al., 2010)
Acacia cyclops ( ooik ans) 1900 339 55
P osopis species (mesqui e) 1800 173 No es ima ed
Acacia mea nsii (black wa le) 2500 131 474
Acacia saligna (Po Jackson) 1900 108 50
Solanum mau i ianum (bugweed) 1800 89 40
Pinus species (pine ees) 3000 77 133
Opun ia species (cac i) 1800 75 95
Melia azeda ach (sy inga ee) 3000 73 No es ima ed
Lan ana cama a (lan ana) 2200 69 32
Hakea species (hakea) 700 64 36
Eucalyp us species (gum ees) 2429 63 274
Ch omolaena odo a a ( i i d weed) 534 43 102
Populus species (popla ees) 1305 15 58
Salix babylonica (weeping willow) 121 12 38
4.5. THE IMPACT OF ALIEN SPECIES
The impac o alien species in Sou h A ica has, as in o he coun ies, a ely been in es iga ed, and whe e i has
been done, he es ima es a e o en in uni s ha a e no di ec ly compa able. To alle ia e he p oblem o
compa ing di e en ypes o impac measu ed in di e en ways, he En i onmen al Impac Classi i ca ion o
Alien Taxa (EICAT) Scheme (Blackbu n e al., 2014) has ecen ly been adop ed by he IUCN. A Socio-Economic
Classi i ca ion o Alien Taxa scheme (SECIAT, Bache e al., 2018) has also ecen ly been de eloped. Howe e , a he
ime o w i ing his epo , hese schemes had no ye been implemen ed in Sou h A ica. The impac o some
species has been o mally assessed a a global scale ( o example E ans, Kumschick & Blackbu n 2016 o bi ds
and Kumschick e al., 2017 o amphibians). These assessmen s a e no used he e, as he speci i c impac s in Sou h
A ica would need o be assessed o a na ional-scale s a us epo .
The e o e, o indica o 8 - Impac o alien species, all species p esen ly all in o he ca ego y o “no assessed”.
Conduc ing Sou h A ican speci i c EICAT and SEICAT assessmen s is a p io i y o u u e epo s (Chap e 8).
The e was, howe e , a ecen exe cise in which expe s we e asked o hei opinion on he impac o lis ed
species (Zengeya e al., 2017). In his s udy, he 552 species lis ed in he NEM:BA A&IS Regula ions we e sco ed
by axon-speci i c expe s acco ding o hei ecological and hei socio-economic impac s (sepa a ely o nega i e
64
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
and posi i e impac s), on a scale om 1 o 10 using wo ding simila o he EICAT scheme. Fo he pu poses o
discussion, he sco es in Zengeya e al. (2017) we e g ouped in o i e ca ego ies ha co espond in spi i o he
i e ca ego ies o he EICAT and SEICAT schemes [1–2 is negligible impac ~ Minimal Conce n (MC) unde EICAT;
3–4 a e a ew impac s ~ Mino (MI); 5–6 is some impac ~ Mode a e (MO); 7–8 a e majo impac s ~ Majo (MR);
and 9–10 a e se e e impac s ~ Massi e (MV)], wi h each axon assigned o a ca ego y acco ding o he maximum
impac sco ed (i.e. he highe o ei he he en i onmen al o socio-economic impac s).
Using he scheme o Zengeya e al. (2017), 25 species we e assessed as ha ing a se e e impac , and 82 as ha ing
a majo impac (Table 4.6). O hese 107 species, mos (80) a e e es ial o eshwa e plan s, eigh a e mammals,
i e each a e eshwa e i sh, eshwa e in e eb a es and e es ial in e eb a es, wo a e amphibians, and
he e is one bi d and one ma ine plan species.
The g ea es impac s associa ed wi h in asi e species in e es ial habi a s a e due o in ading plan s (Table 4.7).
Depending on he species, hey can educe angeland condi ion and ca ying capaci y, educe su ace wa e
uno and g oundwa e echa ge, inc ease i e haza ds, and e ode biodi e si y. When in oduced o o sho e
islands, hey can impe il island auna and l o a (Box 5.3). In a e iew o he s a e o knowledge ega ding he
impac s o in asi e plan s in Sou h A ica, Richa dson & Van Wilgen (2004) concluded ha , wi h he no able
excep ion o he impac s o woody plan s on wa e esou ces, e y li le was documen ed. Al hough he e ha e
subsequen ly been addi ional s udies, he impac s o he as majo i y o in asi e species emains uns udied.
One no able excep ion is p o ided by in asi e ees in he genus P osopis (mesqui e ees), whe e a leas en
sepa a e s udies ha e documen ed impac s on indigenous in e eb a es, bi ds, mammals, ees and g asses,
angeland condi ion, g oundwa e echa ge and human heal h in bo h biophysical and economic e ms (Box
4.2). In some cases, indigenous knowledge sys ems p o ide aluable insigh s in o impac . Fo example,
Shackle on e al. (2017b) used semi-s uc u ed ques ionnai es o assess local pe cep ions associa ed wi h
in asi e cac i in Laikipia Coun y, Kenya. This s udy was use ul in iden i ying and anking he main impac s
associa ed wi h he species conce ned, and his app oach could be used mo e o en in u u e o expand
knowledge. Finally, some species can ha e bo h posi i e and nega i e impac s (Box 4.3), and hese cases p esen
special challenges when i comes o i nding accep able and sus ainable app oaches o hei managemen .
In eshwa e ecosys ems, in asi e i sh and c us aceans, as well as he diseases hey ca y, can ha e la ge impac s
on indigenous eshwa e bio a. Again, well-documen ed cases a e a e, bu a small numbe o obus s udies
exis . Fo example, Shel on, Samways & Day (2014) documen ed he impac s o Onco hynchus mykiss ( ainbow
ou ) in he i e s and s eams o he Cape Flo is ic Region (CFR). They ound mean densi ies o indigenous
Pseudoba bus bu chelli (B eede Ri e ed i n), Sandelia capensis (Cape ku pe ) and Galaxias zeb a us (Cape galaxias),
we e 89–97% lowe in in aded s eams han in s eams wi hou ou . Fu he mo e, while indigenous i sh we e
p esen a 100% o all si es wi hou ou , hey we e no eco ded a all a 58% o he in aded si es. The s udy
concluded ha alien ou ha e deple ed he abundance o CFR-endemic i shes h ough size-selec i e p eda ion.
O he 93 alien ma ine species eco ded, impac was assessed o only 12 species. As such, acco ding o he scheme
used he e, 81 species a e da a de i cien , 2 ha e ew impac s, 7 ha e negligible impac s, 5 ha e some impac s and 2
ha e majo impac s (T. Robinson & C. G i i hs unpublished da a). Fi e species ha e economic o human heal h
impac s, bu hese ha e no been o mally assessed. My ilus gallop o incialis (Medi e anean mussel) is belie ed o
ha e he g ea es impac s in Sou h A ican ma ine en i onmen s. Fi s eco ded in he la e 1970s, his species
p esen ly occupies mo e han 2000 km o coas line, occu ing along he whole o he Wes Coas and as a eas as
Eas London (Robinson e al., 2005). Wi hin i s ange, his mussel impac s on a a ie y o indigenous species and
65
CHAPTER 4
I
THE STATUS OF ALIEN SPECIES
ul ima ely has al e ed he s uc u e o ocky sho e communi ies. Along he Wes Coas M.gallop o incialis domina es
p ima y ock su aces a he expense o a ious compe i i ely in e io indigenous mussel and limpe species (B anch
& S e ani, 2004; Robinson e al., 2007), while along he Sou h Coas i co-exis s wi h he indigenous mussel Pe na
pe na (Linnaeus) (Bownes & McQuaid 2006). In e es ingly, his mussel has also inc eased he di e si y and abundance
o indigenous auna on in aded sho es, as i o ms complex mussel beds ha inc ease habi a a ailabili y o
indigenous bio a (Robinson e al., 2007, Sadcha heeswa an, B anch & Robinson 2015). This change in habi a
s uc u e has signi i can ly al e ed ocky sho e communi ies. The i e species ha ha e some impac s a e Saga ia
o na a (b ooding sea anemone), Ficopoma us enigma icus (es ua ine ube-wo m), Balanus glandula (Paci i c
ba nacle), Semimy ilus algosus (paci i c mussel) and Ciona in es inalis (sea ase). These in asions ha e esul ed in
popula ion-le el changes in indigenous species. The mos ecen ly a i ed species, S. algosus is pa icula ly
conce ning. This mussel was i s de ec ed along he Wes Coas in 2009 (De G ee , G i i hs & Zeeman 2013) bu has
ecen ly c ossed he biogeog aphic ba ie o Cape Poin and now occu s in False Bay (T. Robinson unpublished
da a). Labo a o y s udies ha e sugges ed ha his mussel could su i e along he Sou h Coas (Alexande e al.,
2015) and his aises conce ns ha he ull ex en o he impac s o his alien a e ye o be ealised.
TABLE 4.6 The numbe o species known o occu in Sou h A ica, assigned o a ious ca ego ies o impac s a us based on expe
opinion o he impac in Sou h A ica. The impac o biological con ol agen s is posi i e, so hey we e no assigned o an impac s a us
hence hey we e ep esen ed as NE (no e alua ed). See ex o de i ni ions o impac s a us.
TAXON
IMPACT
DATA
DEFICIENT NEGLIGIBLE FEW SOME MAJOR SEVERE NOT
EVALUATED TOTALS
Amphibians 15 1 2 1 2 0 0 21
Bi ds 0 5 5 8 1 0 73 92
F eshwa e i sh 1 0 5 9 4 1 6 26
F eshwa e
in e eb a es 0 7 9 4 1 4 4 29
Mammals 0 4 16 11 8 0 3 42
Ma ine
in e eb a es 73 2 1 4 1 0 4 85
Ma ine plan s 8 0 0 0 0 0 0 8
Mic obial species 0 6 0 1 0 0 103 110
Rep iles 18 11 11 8 0 0 80 128
Te es ial and
eshwa e plan s 2 48 116 133 63 17 514 893
Te es ial
in e eb a es 5 94 16 20 2 3 460 600
To als 122 178 181 199 82 25 1247 2034
Twen y- i e species we e conside ed o ha e a se e e impac (Table 4.7). Mos o hese (17 species) we e plan s,
which included se en species o Aus alian ees and sh ubs in he genus Acacia. The lis also included some
examples o se e e impac by species in o he high-le el axa, including one eshwa e i sh species, one
amphibian species, h ee e es ial mollusc species, and one e es ial insec species.
66
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
TABLE 4.7 In asi e species assessed based on expe opinion o ha e se e e impac s in Sou h A ica. The egula o y ca ego y
“con ex speci i c” applies o species ha ha e been placed in o a ious ca ego ies depending on hei loca ion.
TAXON SPECIES
REGULATORY
CATEGORY
EXTENT
(QDGCs
occupied)
EXAMPLES OF IMPACTS
TERRESTRIAL AND FRESHWATER PLANTS
Acacia cyclops ( ooik ans) 1b 115 Fo ms closed-canopy s ands, excluding mos o he species; dis up s
na u al sand mo emen in coas al ecosys ems; inc eases i e in ensi y,
leading o soil damage and e osion
Acacia dealba a
(sil e wa le)
2 240 Fo ms closed-canopy s ands, excluding mos o he species, especially
in ipa ian a eas; uses excessi e amoun s o wa e
Acacia decu ens and hyb ids
(g een wa le)
2 105 Fo ms closed-canopy s ands, excluding mos o he species, especially
in ipa ian a eas; uses excessi e amoun s o wa e
Acacia longi olia
(long lea ed wa le)
1b 53 Fo ms closed-canopy s ands, excluding mos o he species; uses
excessi e amoun s o wa e
Acacia mea nsii and hyb ids
(black wa le)
2 369 Fo ms closed-canopy s ands, excluding mos o he species, especially
in ipa ian a eas; uses excessi e amoun s o wa e
Acacia melanoxylon
(Aus alian blackwood)
2 124 Widesp ead in ade in o es s and o es eco ones. Excludes
o he species
Acacia saligna
(Po Jackson)
1b 126 Fo ms closed-canopy s ands, excluding mos o he species
Ag os is s oloni e a
(c eeping ben g ass)
Con ex
speci i c
O sho e
islands
Fo ms ex ensi e clonal pa ches by means o long s olons, impac ing
on indigenous plan species on o sho e islands
Ch omolaena odo a a
( i i d weed)
1b 110 Can domina e in g assland and sa anna ecosys ems, especially in
dis u bed a eas, and educes biodi e si y and angeland p oduc i i y
Dolichand a unguis-ca i
(ca ’s claw c eepe )
1b 44 A climbing ine ha in ades o es s, woodlands and o es ma gins,
smo he ing and collapsing ees
Echium plan agineum
(Pa e son’s cu se)
1b 104 An in ade o pas u es and cul i a ed lands
Eucalyp us camaldulensis
( i e ed gum)
Con ex
speci i c
136 Fo ms closed-canopy s ands in ipa ian a eas, excluding mos o he
species; uses excessi e amoun s o wa e
Hakea se icea
(silky hakea)
1b 39 Fo ms closed-canopy s ands in ynbos moun ain ca chmen s, and
displaces mos o he species. Inc eases i e in ensi y, leading o soil
damage and excessi e e osion
Lan ana cama a (lan ana) 1b 312 Widesp ead in asi e sh ub ha can domina e in sa anna and
g assland egions, and educes biodi e si y and angeland p oduc i i y
P osopis glandulosa a .
o eyana (honey mesqui e)
Con ex
speci i c
112 Many well-documen ed impac s on biodi e si y, g oundwa e supplies,
angeland p oduc i i y and human li elihoods and heal h (see Box 4.2)
P osopis elu ina
( el e mesqui e)
Con ex
speci i c
5Many well-documen ed impac s on biodi e si y, g oundwa e supplies,
angeland p oduc i i y and human li elihoods
TERRESTRIAL
INVERTEBRATES
Co nu aspe sum
(common ga den snail)
Unlis ed 115 Pes i e ous, documen ed o damage o comme cial and o namen al
c ops, as well as domes ic ga dens
De oce as in adens
( amp slug)
Unlis ed 10 Pes o ga den ege ables
Linepi hema humile
(A gen ine an )
1b 36 Dis up s seed dispe sal mechanisms in ynbos, po en ially leading o
collapse o plan ep oduc ion sys ems
FRESHWATER
INVERTEBRATES
Che ax quad ica ina us
( edclaw c ay i sh)
1b 3 Nega i ely impac s indigenous eshwa e species. I also ca ies
pa asi es which could ha e u he impac s on indigenous species
Schyzoco yle acheilogna hi
(Asian apewo m)
Unlis ed 5 A pa asi e in oduced on alien i sh ha a acks indigenous i sh species
Pseudodac logy us anguillae
(gill l ukes)
Unlis ed 2 A pa asi e in oduced on alien i sh ha a acks indigenous i sh species
P ocamba us cla kii
( ed swamp c ay i sh)
P ohibi ed 4 Physical damage o aqua ic habi a s; dis up s nu ien cycling; p eys on
indigenous species
FRESHWATER
FISH
Mic op e us dolomieu
(smallmou h bass)
Con ex
speci i c
60 P eda o y i sh ha nega i ely impac s indigenous i sh and eshwa e
in e eb a es

67
CHAPTER 4
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THE STATUS OF ALIEN SPECIES
BOX 4.2 PROSOPIS TREES IN SOUTH AFRICA:
AN INVASIVE SPECIES WHOSE IMPACTS HAVE BEEN WELL DOCUMENTED.
T ees in he genus P osopis (mesqui e; Fabaceae)
include se e al species and hei hyb ids ha a e
among he wo ld’s mos damaging in asi e
plan s. Mesqui e ees we e in oduced o Sou h
A ica o p o ide odde and shade o li es ock,
bu as elsewhe e in he wo ld hey ha e become
in asi e, gene a ing nega i e impac s. P osopis
is one o he ew in asi e alien axa whose
ecological and economic impac s ha e been
well s udied and documen ed.
Thicke o P osopis – A ne Wi
Ten indi idual s udies we e conduc ed in A ica be ween 1996 and 2016, in which impac s o P osopis we e
quan i i ed. This knowledge was used o unde pin an economic assessmen o he ne wo h o he genus.
The indi idual aspec s s udied, and he i ndings, a e summa ised he e.
Dung bee le di e si y: In asion educed he numbe o dung bee le species om 41 o 34, and educed hei
densi y ma kedly. La ge species, and a e species, showed he bigges declines.
Bi d di e si y: Bi d communi ies in in aded si es we e ound o be less species- ich and less di e se; ap o s
we e elimina ed, ugi o es became spa se and he numbe o insec i o e species was hal ed in in aded
si es. O he bi d eeding guilds (nec a i o es, seedea e s) we e less a ec ed.
Indigenous zeb a species: In E hiopia, in asion signi i can ly educed he co e o pe ennial g asses om 68%
o 2%, inc eased soil su ace exposu e om 30% o 80%, and lowe ed he numbe o g ass species om
se en o wo. This has pa icula ly nega i e implica ions o he su i al o an isola ed popula ion o he
endange ed G e y’s zeb a (Equus g e yi).
G azing capaci y: In asion by P osopis wi h only 15% co e educed g azing capaci y by 34%, bu clea ing
imp o ed g azing capaci y by 110% wi hin 6 yea s.
Densi y and species ichness o indigenous plan s: In asion educed he densi y, ichness and di e si y o
indigenous plan s. Fo example, indigenous ees declined om eigh o h ee species when in asions
doubled in densi y, and he co e o indigenous pe ennial g asses and he baceous plan s declined om
15–20% o ze o.
In e -speci i c compe i ion wi h indigenous ees: In asi e P osopis and indigenous Acacia e ioloba we e ound
o compe e o g oundwa e , inc easing he likelihood o mo ali y in A. e ioloba in imes o s ess.
G oundwa e le els: In asions by deep- oo ed P osopis ees educed g oundwa e le els.
Economic consequences o in asion: The alue o bene i s o P osopis was ound o ma ginally exceed he cos
o impac s, bu his was p edic ed o change wi hin a ew yea s as P osopis con inues o sp ead, esul ing in
ne nega i e impac s ha will g ow o e ime.
Heal h consequences: A s udy in Mali, Wes A ica, demons a ed ha illages wi h P osopis in asions
suppo ed h ee imes mo e Anopheles mosqui oes, hus inc easing he isk o con ac ing mala ia.
Key e e ences:
Mulle e al. (2017); Shackle on e al. (2014); Wise, Van Wilgen & Le Mai e (2012).
68
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
BOX 4.3 EXAMPLES OF CONFLICT SPECIES THAT CAN BE SIMULTANEOUSLY BENEFICIAL
AND HARMFUL
Alien species can simul aneously b ing many bene i s and cause subs an ial en i onmen al ha m, e y
o en leading o con l ic s o e hei managemen . The impac s g ow o e ime as in asions sp ead, and as
socie al pe cep ions o he alue o alien species change as unde s anding g ows and as alues shi . The
managemen o hese “con l ic ” species is pa icula ly challenging, and equi es ade-o s i bene i s a e o be
maximised and ha m minimised. Some o he p ominen con l ic species in Sou h A ica a e desc ibed he e.
Pine ees (Pinus species) we e plan ed
ex ensi ely in Sou h A ica a e he 1930s o
p o ide imbe . Plan ed pines ha e in aded he
adjacen ynbos in he Cape Flo is ic Region.
In asion by alien pine ees was ecognized as a
p oblem as ea ly as he 1940s, and coo dina ed
a emp s o clea hese in asions began in he
1970s, bu despi e his, in asions a e g owing.
Bo h he need o p e en wa e and biodi e si y
loss and o s imula e economic g ow h a e
becoming mo e acu e, leading o pola ized iews
ega ding he ad an ages and disad an ages o
pines. To da e, sui able comp omises ha e no
been ound, no do hey seem possible.
Pho og aphe : B. an Wilgen
Rainbow ou (Onco hynchus mykiss) we e
delibe a ely in oduced o Sou h A ica o c ea e
sel -sus aining popula ions ou side o cap i i y
o cul i a ion. T ou in oduc ions suppo
ec ea ional and comme cial i she ies ha
con ibu e o he economy. These in en ional
Pho og aphe : Cape Na u e
in oduc ions con inue o occu despi e changing iews on he s ocking o non-indigenous species due o
hei demons a ed ecological impac s. A majo p oblem wi h managing in asi e ou is ha once
es ablished, con ol is ex emely di i cul . Implemen ing managemen in e en ions is also complica ed by
he economic con ibu ions o angling and aquacul u e, and by esis ance om angle s who ac i ely suppo
con inued s ocking. A emp s by go e nmen o add ou o he lis o egula ed species ha e ailed o da e,
and a managemen impasse con inues.
Malla ds (Anas pla y hynchos), ha e been widely
in oduced in o Sou h A ica, whe e e al malla ds
in e b eed wi h he indigenous Yellow-billed Duck
(Anas undula a). A emp s o emo e malla ds by
he Ci y o Cape Town we e e ec i ely hal ed
because he a gumen s o he campaign
(gene ic con amina ion o a single indigenous
species) we e less con incing o he public han
Pho og aphe : S. Tu ne
a gumen s o he widesp ead ecological impac s o mo e damaging in asi e species.
69
CHAPTER 4
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THE STATUS OF ALIEN SPECIES
4.6. SYNTHESIS AND INDICATOR VALUES
The analysis o he numbe o alien species and hei in oduc ion s a us in Sou h A ica is based on he 2034
species lis ed in Appendix 3. Because in oduc ion s a us is no eco ded explici ly in da abases, i was necessa y
o make se e al assump ions, and hese need o be es ed in u u e epo s. Fo many axa, i was no possible o
assign species o a ca ego y o in oduc ion s a us due o a lack o in o ma ion. Howe e i is clea ha Sou h
A ica has a majo in asion deb . Well o e 100 new alien plan axa ha e been eco ded as escaped om
cul i a ion in he pas decade, and he eco ded ange o almos all in asi e plan s has inc eased signi i can ly
(Hende son & Wilson 2017). This is a majo cause o conce n, as i clea ly indica es ha he p oblems associa ed
wi h alien species a e se o inc ease.
Es ima es o species ex en we e limi ed o 835 axa o which eliable dis ibu ion da a we e a ailable. Le els o
con i dence in hese es ima es a e mode a e o e es ial and eshwa e plan s and o bi ds, bu low o o he
axa. This can o m he basis o acking changes in ange o e ime.
The e a e no ecen eliable es ima es o alien species abundance. Fo alien plan s, he e a e es ima es made by
Le Mai e, Ve s eld & Chapman (2000), bu hese a e c ude and mo e han 20 yea s ou o da e. Es ima es made
by Ko zé e al. (2010) do no co e he whole coun y, a e es ic ed o ce ain axa, g oup some species by genus
o amily, and he e is unce ain y ega ding he me hodology employed. I is he e o e no possible a his s age
o p o ide es ima es o indi idual species abundance.
Finally, he issue o quan i ying he impac s o alien species emains a challenge. Fo he as majo i y o species,
no s udies documen impac s, and he e ha e been almos no o mal assessmen s o impac using ei he he
EICAT o SEICAT schemes a he scale o Sou h A ica. This assessmen he e o e had o ely on expe opinion o
assign species o ca ego ies o impac . This, howe e , is no sui able o p esen ing as an indica o , as he
me hodology is no epea able. Fo mal assessmen s a e equi ed o he nex epo i ends in impac a e o be
acked. In he mean ime, his epo does no assign alues o impac indica o s in Table 4.8, al hough he
es ima e based on expe opinion is p esen ed in he high-le el indica o s in Table 6.9.
Cac i a e among he mos dominan in asi e
plan g oups in Sou h A ica, whe e hey impac
nega i ely on biodi e si y, ecological unc ioning
and ag icul u al p oduc i i y. Cac i a e also
impo an o namen al plan s, and a ound 300
species o cac i a e impo ed o Sou h A ica
annually, and he ade in hese plan s
con ibu es o he economy. A managemen
amewo k has been de eloped in which ou
s a egic objec i es we e p oposed:
Pho og aphe : SANBI
(1) all in asi e and po en ially in asi e cac us species should be p e en ed om en e ing he coun y, (2)
new incu sions o cac us species mus be apidly de ec ed and e adica ed, (3) he impac s o in asi e cac i
mus be educed and con ained, and (4) use ul cac i (bo h in asi e and non-in asi e species) mus be u ilised
sus ainably o minimise he isk o u he nega i e impac s.
70
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
TABLE 4.8 Indica o s used o epo ing on he s a us o alien species. Fo ull de ails o how o calcula e he indica o s, see
Appendix 1.
INDICATOR METRIC
BASIC ADVANCED
LEVEL OF
CONFIDENCE NOTES
5. Numbe and
s a us o alien
species
5.1. Numbe o
in asi e species:
775
5.2. Numbe o alien
species in ca ego ies
Alien bu no
na u alised: 355
Na u alised bu no
in asi e: 388
In asi e: 775
No assessed: 516
Numbe o
species in each
o 12 s ages
No da a
Low S a us no explici ly o
consis en ly eco ded in
da abases, so
assump ions we e used.
These numbe s ocus on
alien species ou side o
cap i i y o cul i a ion
( his was no cap u ed
consis en ly). A census
o all aliens is needed
6. Ex en o alien
species
6.1. Ex en o
species pe
p o ince (based
on 835 species o
known ex en ).
(see Figu e 4.1)
6.2. A a qua e -
deg ee g id cell scale,
many species ha e a
limi ed dis ibu ion,
wi h some being
ela i ely widesp ead
(see Figu e 4.1; and
Figu e 4.3).
6.3. Range size
o each species
No da a
Mode a e o
e es ial and
eshwa e
plan s and
bi ds; low o
all o he axa
Plan s and bi ds a e
conspicuous and he
ele an a lases a e
egula ly upda ed
7. Abundance o
alien species
7.1. Ca ego ical
measu e o
abundance
No da a
7.2. Numbe o
indi iduals o a ea
occupied
No da a
7.3. Abundance
es ima es by
s ages o age
coho s.
No da a
N/A The e a e only
abundance da a o
alien plan s, bu hese
a e c ude and 20 yea s
ou o da e
8. Impac o
alien species
8.1. Numbe o
species in impac
ca ego ies
No da a
8.2. De ailed impac s
pe species o a ange
o impac mechanisms
No da a
N/A Species ha e been
placed in o impac
ca ego ies based on
expe opinion, and
hese a e p esen ed in
he ex , bu no species
ha e been o mally
assessed acco ding o
EICAT o SEICAT
guidelines
B. Numbe o
species wi h
majo impac s
107 species No applicable Based en i ely on expe
opinion, and so does
no ep esen an
app op ia e base-line
77
CHAPTER 5
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5.2.3. Alien species ichness a di e en s ages o he Uni i ed F amewo k o Biological
In asions
I he size o he u u e p oblems on biological in asions is o be es ima ed, hen spa ial da a on he numbe o
species a di e en s ages along he in oduc ion-na u alisa ion-in asion con inuum would be equi ed (i.e.
a ea-based in asion deb ). Howe e , he in oduc ion s a us o all alien species is no known o any g oups.
5.3. RELATIVE ALIEN SPECIES RICHNESS
Es ima es o Rela i e alien species ichness a p o incial scales could only be made o in asi e axa o which
eliable dis ibu ion da a we e a ailable (plan s and bi ds). Rela i e in asi e bi d species ichness pe p o ince
anged om 1.0% in Limpopo o 1.6% in he F ee S a e. Rela i e in asi e plan species ichness pe p o ince
anged om 7% in he No he n Cape o 25% in he No hwes . No e ha he numbe o indigenous plan
species is based on BODATSA, which has incomple e eco ds.
This indica o will be o alue o managemen when used in conce wi h Alien species ichness and Rela i e
in asi e abundance a an app op ia e scale, e.g. pe p o ec ed a ea, o managemen zone, and as acked o e
ime. Howe e , hese da a a e no a ailable a p esen .
5.4. RELATIVE INVASIVE ABUNDANCE
The e a e no eliable es ima es o in asi e plan species co e o biomass pe p o ince (Box 5.1). C ude es ima es
made by Ve s eld, Le Mai e & Chapman (1998) con i med wha is gene ally accep ed, namely ha he Wes e n
Cape is he mos in aded p o ince, ollowed by Mpumalanga, No he n Cape and KwaZulu-Na al. App oxima ely
28% o he a ea o he Wes e n Cape was in aded by alien plan s a a ange o co e classes, wi h he mos
impo an axa being wa les (genus Acacia), pines (genus Pinus) and hakeas (genus Hakea). App oxima ely
16% o he a ea o he Mpumalanga was in aded by alien plan s a a ange o co e classes, wi h he mos
impo an axa being wa les (genus Acacia), Lan ana cama a (lan ana) and Solanum mau i ianum (bugweed).
In asions in he No he n Cape P o ince we e domina ed by mesqui e ees (genus P osopis), which accoun ed
o almos all o he in asions ha co e ed 14% o he p o ince a he ime. In KwaZulu-Na al, whe e in asions
co e ed 9% o he p o ince, he mos impo an con ibu ing axa we e wa les (genus Acacia), Ch omolaena
odo a a ( i i d weed), cac i (in pa icula he genus Opun ia) and Solanum mau i ianum (bugweed). O he
p o inces we e all es ima ed o ha e less han 3% co e by in asi e alien plan s (wi h he admission ha he
Eas e n Cape P o ince was subs an ially unde -sampled by Ve s eld, Le Mai e & Chapman (1998). These
es ima es, besides being c ude, a e mo e han 20 yea s ou o da e, and bo h he ex en o in asions and he
ela i e dominance o species, ha e changed conside ably since hen (Hende son & Wilson, 2017). A mo e
ecen es ima e by Ko zé e al. (2010) con i med Acacia mea nsii (black wa le) as he mos abundan in asi e
alien plan species, ollowed by gum ees (Eucalyp us species), pine ees (Pinus species) and Ch omolaena
odo a a ( i i d weed, see Table 4.5). Howe e , he s udy by Ko zé e al. (2010) only a ge ed alien plan species
o in e es o he Wo king o Wa e p og amme (mainly ees and sh ubs), excluded a e y la ge p opo ion o
a id Sou h A ica, and is based on me hodology ha has no been adequa ely documen ed. As a esul , he e
can only be a low deg ee o con i dence in he es ima es a his s age.

78
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
5.5. IMPACT OF INVASIONS
While he impac s o indi idual in asi e species ha e been quan i i ed in a numbe o cases, i.e. Alien species
impac , such s udies a e a e (Box 4.2). Fewe s udies ha e a emp ed o quan i y he combined impac s o co-
occu ing in asi e species on a pa icula a ea, i.e. Impac o in asions. In Sou h A ica, some wo k has been done
o quan i y he impac s o in asi e plan s on selec ed ecosys em se ices o ecosys em in ac ness, ei he a a
biome scale ( o wa e esou ces, li es ock p oduc ion om na u al angelands, and o biodi e si y in ac ness,
Van Wilgen e al., 2008), o a a ca chmen scale o wa e esou ces (Le Mai e e al., 2000; 2016). The i ndings o
hese s udies a e summa ised below.
5.5.1. Impac s on su ace wa e uno and g oundwa e by p ima y ca chmen
The ad e se impac s o alien plan in asions on wa e l ows ha e p o ided a s ong a gumen o he con ol o
in asi e plan s (Le Mai e e al., 1996; Van Wilgen, Cowling & Bu ge s 1996). Le Mai e, Ve s eld & Chapman (2000)
es ima ed ha he o al educ ion in uno due o in ading alien plan s was abou 3 300 million m3 pe yea , o
abou 7% o he coun y’s mean annual uno . Abou a hi d o his es ima ed wa e use, by olume, was
accoun ed o by in asi e plan s in he Wes e n Cape, ollowed by KwaZulu-Na al (17%), he Eas e n Cape (17%)
and Mpumalanga (14%). This sec ion summa ises cu en es ima es o he impac s on wa e l ows o p ima y
ca chmen s and biomes and highligh s he species wi h he g ea es impac s. The educ ions ake he o m o
changes in uno om in aded d yland a eas due o inc eased e apo a ion, and e apo a ion o g oundwa e
om in aded i e l oodplains ( ipa ian in asions) and om in aded a eas wi h g oundwa e in aqui e s accessible
o oo sys ems (g oundwa e ). The o al educ ion is exp essed as a p opo ion o mean annual uno because
all hese educ ions ul ima ely esul in a educ ion in su ace wa e uno as measu ed in i e s.
Le Mai e e al. (2016) subsequen ly used new in o ma ion on he dis ibu ion o in asi e alien plan s, and
imp o ed l ow educ ion models, o pu o wa d a e ised es ima e o 1 444 million m3 pe yea , o 2.9% o he
na u alised mean annual uno (less han hal o he 3 300 million m3 pe yea es ima ed in 2000). Two main
ac o s accoun ed o he di e ence be ween he es ima es o Le Mai e, Ve s eld & Chapman (2000) and hose o
Le Mai e e al. (2016). The i s was a dec ease in he es ima ed uni -a ea l ow educ ion o 970 m3 pe ha pe yea
compa ed wi h 1 900 m3 pe ha pe yea es ima ed in 1998, la gely due o e i nemen s o he models. The second
was he use o a smalle es ima ed in aded a ea (alien plan s ha co e ed 1 million ha compa ed o he 1.76
million ha used in he 2000 assessmen ). This was due o he use o a new alien plan dis ibu ion da a se (Ko zé
e al., 2010) ha excluded Sou h A ica’s a id in e io and hus he en i e Nama Ka oo, almos all o he Succulen
Ka oo and Dese biomes, abou a hi d o he Sa anna, and hal o he G assland biome. This mean ha he
2016 i gu e o wa e use by in asi e plan s was an unde -es ima e.
In addi ion, he e ised es ima e was also conside ed o be an unde es ima e by Le Mai e e al. (2016) because
he ex en and impac s o ipa ian in asions had been unde es ima ed. The es ima e o Le Mai e e al. (2016) o
1 444 million m3 pe yea was based on he mapped da a showing ha only 4–6% o in asions o some o he
majo con ibu ing axa (Acacia mea nsii, black wa le, Eucalyp us, gum ees, Populus, popla ees, and Salix,
willows) we e ound in ipa ian zones (whe e wa e use is highe ). Howe e , he ac ual p opo ion o hese axa
in ipa ian zones is p obably much highe , and his could inc ease he es ima e by as much as 70%, om 1444
o 2444 million m3 pe yea .
79
CHAPTER 5
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THE STATUS OF INVADED AREAS
Impac s on su ace wa e uno by p ima y ca chmen : The la ges educ ions (o e 5% o mean annual uno ) we e
in he Wes e n Cape (ca chmen s G, H and K), he Eas e n Cape (ca chmen s K, M and R), and KwaZulu-Na al
(ca chmen U) (Table 5.3). Only abou 5% o he O ange Ri e sys em (ca chmen D) was mapped, as was only
abou 33% o he Vaal Ri e sys em, so he o al educ ions in hese ca chmen s we e signi i can ly unde es ima ed.
The main di e ence om he 2000 es ima e is he much g ea e es ima ed educ ions in ca chmen s in he Eas e n
Cape (whe e alien plan in asions we e inadequa ely accoun ed o in he 2000 es ima e).
TABLE 5.3 The es ima ed ex en o educ ions in su ace wa e uno due o in asi e alien plan s in Sou h A ica’s p ima y
ca chmen s. Table adap ed om Le Mai e e al. (2016). Condensed ha is he equi alen a ea occupied a a canopy co e o 100%
(i.e. 50% co e on 10 ha = 5 condensed ha). See Figu e 5.3 o he loca ion o p ima y ca chmen s.
PRIMARY
CATCHMENT RIVER SYSTEMS ESTIMATED INVASION
LEVEL (CONDENSED HA)
ESTIMATED REDUCTION
(MILLIONS OF m3)
ESTIMATED REDUCTION
(% OF MEAN
ANNUAL RUNOFF)
A C ocodile-Limpopo 86510 24.44 1.06
B Oli an s-Le aba 123328 61.79 2.13
C Vaal 138557 64.25 1.53
D O ange 54383 31.57 0.46
E Oli an s-Do ing 4825 3.65 0.31
F Namaqualand coas 795 0.00 0.02
G Be g-Agulhas 92970 111.36 6.04
H B eede-Goukou 45164 126.21 6.11
J Gou i z 25438 11.69 1.86
K Ha enbos-K omme 60951 102.51 8.43
L Gam oos 24228 10.86 2.09
M Swa kops 23662 11.64 6.46
N Sundays 39906 0.89 0.34
P Bushmans 12432 3.31 1.99
Q G ea Fish 30385 4.83 0.90
R Keiskamma-Nahoon 45414 42.92 7.41
S G ea Kei 59130 46.58 4.49
T Umbashe-Umzim ubu 220942 321.96 4.51
U uMzimkulu-uM o i 111698 154.35 5.03
V Thukela 81139 100.87 2.60
W uM olozi-Pongola 154984 148.66 2.31
X Incoma i 58025 59.19 1.90
To al 1494867 1443.56 2.88
80
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
FIGURE 5.3 Es ima es o he educ ions in mean annual uno (MAR) due o in asi e alien plan s in he qua e na y ca chmen s
o Sou h A ica. Capi al le e s e e o p ima y ca chmen s. The qua e na y ca chmen s ha we e comple ely excluded a e shown in
g ey; many o he s we e only pa ially mapped; he K uge Na ional Pa k was also excluded. Map: DLeMai e unpublished da a.
Impac s on su ace wa e uno by biome: Al hough some biomes we e excluded o only pa ially mapped by
Ko zé e al. (2010), he da a show ha while he G assland Biome and he we e a eas o he Sa anna Biome
(i.e. excluding he Kalaha i) ha e he mos ex ensi e in asions, he mos hea ily in aded ones a e he Indian
Ocean Coas al Bel and Fynbos. The in asions and impac s o he Fo es biome (Table 5.4) a e o e es ima ed,
due o mapping scale misma ches. This means ha he g ea es pe cen age educ ions a e ound in he
Indian Ocean Coas al Bel and in he Fynbos biome. Howe e , he olume o he educ ion o he G assland
is o pa icula conce n because he su ace uno om his biome is c i ical o wa e supplies o Gau eng,
he EThikweni Region and Mangaung, as well as o powe gene a ion and much o he i iga ed ag icul u e
in Sou h A ica.
81
CHAPTER 5
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TABLE 5.4 The es ima ed impac s on he annual su ace wa e uno o all in asions in he biomes included in he landscape
mapping o he RSA by Ko zé e al. (2010). MAR = mean annual uno .
STATISTIC
BIOME
ALBANY
THICKET FOREST FYNBOS GRASSLAND INDIAN OCEAN
COASTAL BELT
SAVANNA
(we e
a eas only)
To al educ ion (million m3/y ) 23 12 365 621 113 309
MAR (million m3/y ) 659 66 5213 16709 1509 7726
Reduc ion (% MAR) 3.48 18.36 6.99 3.72 7.52 4.00
The a ailable es ima es o he impac o in asi e plan s on su ace wa e uno om ca chmen s he e o e a e
unde es ima es and, a bes , coa se app oxima ions, due o he issues ega ding he accu acy o he mapping
and he numbe o assump ions and ex apola ions ha had o be made. Fu he esea ch is needed o p o ide
be e es ima es o he impac s.
In he 2016 es ima e, he axon wi h he g ea es es ima ed impac was wa les (Acacia mea nsii, black wa le,
A.dealba a, sil e wa le, and A. decu ens, g een wa le) which accoun ed o 34% o he educ ions, ollowed by
Pinus species (pine ees) (19.3%) and Eucalyp us species (gum ees) (15.8%) (Table 5.5). Nea ly 70% o he
wa le in asions, 60% o gum ees, 40% o pines and mos o he popla and willow in asions a e in he G assland
biome and explain why es ima ed educ ions in his biome a e so hig. P osopis (mesqui e) in asions in he
No he n Cape we e mapped in 2007 (Van den Be g 2010) and his in o ma ion was used o es ima e a educ ion
o abou 9 million m3/y , mos o his being in he O ange Ri e ca chmen (Le Mai e e al., 2013).
TABLE 5.5 A compa ison o he es ima ed ex en and impac o in asions by di e en axa on he mean annual su ace wa e
uno in Sou h A ica (Middle on & Bailey 2008) based on he landscape mapping o he RSA by Ko zé e al. (2010). Condensed ha is
he equi alen a ea a a canopy co e o 100% (i.e. 50% co e on 10 ha = 5 condensed ha)
ESTIMATED
CONDENSED AREA
(HA)
ESTIMATED
REDUCTION
(MILLION M3)
ESTIMATED REDUCTION
(MM RAINFALL
EQUIVALENT)
Acacia cyclops ( ooik ans) 54679 28.95 53
Acacia mea nsii (black wa le) 474489 483.23 102
Acacia melanoxylon (Aus alian blackwood) 2796 18.07 646
Acacia saligna (Po Jackson willow) 50052 11.66 23
Aga e spp. (Cen u y plan s) 11341 0.89 8
A undo donax (gian eed) 3202 1.59 50
A iplex nummula ia (old man sal bush) 5862 0.94 16
Caesalpinia decape ala (Mau i ius ho n) 8830 10.95 124
82
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
ESTIMATED
CONDENSED AREA
(HA)
ESTIMATED
REDUCTION
(MILLION M3)
ESTIMATED REDUCTION
(MM RAINFALL
EQUIVALENT)
Ce eus jamaca u (queen o he nigh ) 10948 0.13 1
Ces um spp. (ces ums) 7217 19.27 267
Ch omolaena odo a a ( i i d weed) 101992 100.29 98
Eucalyp us spp. (gum ees) 273573 217.37 79
Hakea spp. (hakeas) 36344 72.20 199
Jaca anda mimosi olia (jaca anda) 4200 1.76 42
Lan ana cama a (lan ana) 32328 40.29 125
Melia azeda ach (se inga) 14224 7.34 52
Opun ia spp. (cac i) 95010 7.70 8
Pinus spp. (pine ees) 132937 272.31 205
Populus spp. (popla s) 58082 26.89 46
P osopis spp. (mesqui e) 5232 1.95 37
Psidium guaja a (gua a) 6354 7.16 113
Rosa ubiginosa (eglan ine) 11801 8.75 74
Salix babylonica (weeping willow) 37555 22.48 60
Senna didymobo ya (peanu bu e cassia) 11586 13.84 119
Sesbania punicea ( ed sesbania) 1683 2.22 132
Solanum mau i ianum (bugweed) 40413 58.20 144
Tama ix chinensis (Chinese ama isk) 2137 7.13 334
To al 1494867 1443.56 97
P ojec ed in asions: The ini ial es ima es o he cos s o con ol and he impac s o in asions we e based on an
inc ease o 5% pe yea (e.g. Le Mai e e al., 2002) bu a syn hesis o he in o ma ion on sp ead sugges s a a e
close o 10% (Van Wilgen & Le Mai e 2013). P ojec ions o he impac s based on inc eases in in asions in he
a ea o he ca chmen s unde na u al ege a ion show ha he impac s a e likely o become subs an ially g ea e .
A an expansion a e o 5%, and densi i ca ion o 1%, he o al educ ion would inc ease o 2589 million m3/y
(5.2% o MAR) in 25 yea s (i.e. in abou 2032). A 10% he p ojec ed educ ions in 25 yea s will be abou 3153
million m3/y (6.3% o MAR). The inc eases in he pe cen age educ ions occu h oughou he mapped a ea bu
a e g ea es in he highe ain all pa s o he Eas e n Cape, Kwa-Zulu-Na al and he Wes e n Cape. The simple
sp ead model did no allow in asions in a ca chmen o sp ead o adjacen ones ha we e no ini ially in aded
so he es ima ed impac s p obably a e conse a i e.
These i ndings ha e signi i can implica ions o wa e secu i y wi hin and downs eam o hese in aded a eas,
highligh ing he need o ocus in es men in a eas whe e i will yield he g ea es long- e m bene i s.

83
CHAPTER 5
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THE STATUS OF INVADED AREAS
FIGURE 5.4 P ojec ed educ ions in he mean annual uno (MAR) in 2032, a di e en a es o sp ead o in asi e alien plan s
(assumed o be 5% in uppe map and 10% in lowe map). Map: D Le Mai e unpublished da a.
84
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
5.5.2. Impac s on angeland p oduc i i y by biome
The impac o in asi e alien plan s on g azing po en ial was assessed o he
Fynbos, G assland, Succulen Ka oo, Nama Ka oo and combined Sa anna and
Thicke biomes by Van Wilgen e al. (2008). They used es ima es o he mean
li es ock p oduc ion o ep esen he po en ial o un-in aded ege a ion o
suppo li es ock p oduc ion, and maps o he ex en o in asion by alien plan
species o es ima e educ ions in li es ock p oduc ion in each biome. They
es ima ed ha cu en educ ions in he po en ial o biomes o suppo g azing
s ock, as a esul in asi e alien plan in es a ions, amoun ed o be ween 200 (in
he Nama Ka oo) and 74500 (in he Fynbos) la ge s ock uni s. This amoun ed o
jus o e 1% o he po en ial numbe o li es ock ha could be suppo ed by
hese ecosys ems. Howe e , hey also es ima ed ha hese impac s could
inc ease o 71% o he po en ial, i in es a ions o in asi e alien plan s we e
allowed o each hei ull po en ial. They no ed ha “while he e o s in hese
es ima es could be la ge, he p edic ed impac s a e o su i cien magni ude o
sugges ha , e en wi h signi i can o e -es ima es, he e is cause o se ious
conce n; o example, e en i he le els o impac a e one en h o hose p edic ed,
hey would esul in signi i can losses o bene i ”.
5.5.3. Impac s on biodi e si y in ac ness by biome
The impac o in asi e alien plan s on biodi e si y in ac ness was also assessed o
he Fynbos, G assland, Succulen Ka oo, Nama Ka oo and combined Sa anna and
Thicke biomes by Van Wilgen e al. (2008). Biodi e si y in ac ness (Scholes & Biggs,
2005) es ima es he impac o land-use changes (in his case in asion by alien
plan s) on popula ions o plan s, mammals, bi ds, ep iles and ogs in a gi en a ea,
and was designed o p o ide an easy- o-unde s and measu e o he s a e o
biodi e si y o policy-make s and he public. A p e ious s udy by (Biggs, Reye s &
Scholes 2006) had es ima ed ha he biodi e si y in ac ness index ange om
71% o 89% o he i e biomes analysed. These es ima es ook he con e sion o
na u al landscapes by means o ag icul u e, o es y o u ban de elopmen , as
well as land deg ada ion in o accoun , bu hey did no accoun o he impac s o
in asi e alien plan s. When he addi ional impac s o in asi e alien plan s we e
conside ed, es ima es o he cu en le els o he biodi e si y in ac ness index
only declined in he Fynbos biome ( om 73% o 70%). I was concluded (Van
Wilgen e al.. 2008) ha his e l ec ed he ac ha he ynbos biome had he
highes le els o alien plan in es a ions, p obably due o he conside ably longe
pe iod o colonial se lemen in he ynbos. Unde a scena io whe e in asi e alien
plan s a e allowed o each hei ull po en ial, howe e , he alues we e p edic ed
o decline d ama ically, o a ound 30% o he sa anna, ynbos and g assland
biomes, bu o e en lowe alues (13% and 4%) o he wo ka oo biomes,
sugges ing signi i can po en ial declines in biodi e si y o > 90% in places.
5.5.4. Impac s on i e egimes
In asion o na u al ecosys ems by alien plan s can change he s uc u e and
biomass o ege a ion, adding uel and suppo ing i es o highe in ensi y.
The p oduc i i y o angelands is
unde se ious h ea om a la ge
numbe o in asi e plan s ha
could po en ially hal e
he p oduc ion o
li es ock om na u al
angeland a eas.
½
85
CHAPTER 5
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THE STATUS OF INVADED AREAS
Inc eased i e in ensi y can in u n inc ease he damage done by i es, as well as he di i cul y o con olling i es.
Al hough he p inciples behind his phenomenon ha e been unde s ood o some ime (B ooks e al., 2004),
he e is e y li le in he way o documen ed impac s in Sou h A ica. Van Wilgen & Richa dson (1985) ound ha
in asion o Fynbos sh ublands by he sh ubs Hakea se icea (silky hakea) and Acacia saligna (Po Jackson willow)
inc eased uel biomass by be ween 50 and 60%, bu ha his could no be shown o inc ease i e in ensi y in an
exis ing i e beha iou p edic ion model. These au ho s concluded ha sho comings in he model p e en ed
he accu a e simula ion o high in ensi y i es which we e known o occu in in aded s ands unde se e e i e
wea he condi ions. Such i es igo ously consume he inc eased biomass o sh ub c owns, and a e di i cul o
con ol. La e wo k demons a ed ha physical damage o he soil can occu a e i e in in aded a eas, esul ing
in inc eased e osion a e i e. Fo example, 6 onnes o soil pe hec a e was los ollowing i es in pine plan a ions
compa ed o 0.1 onnes pe hec a e ollowing i e in adjacen Fynbos in he Wes e n Cape (Sco , Ve s eld, Lesch
1998). While pine plan a ions a e no s ic ly equi alen o in aded si es, he compa ison is alid as plan a ions
a e no mally es ablished in Fynbos si es wi h almos no soil. A u he s udy (Van Wilgen & Sco , 2001) compa ed
soil damage ollowing i es in ege a ion in aded o di e en deg ees on he Cape Peninsula. This s udy ound a
ela ionship be ween he deg ee o in asion and he physical damage o he soil, especially be ween si es ha
we e unin aded, o ligh ly in aded, compa ed o hea ily in aded si es. In asions o i e-p one a eas by la ge ees
and sh ubs can he e o e be expec ed o esul in se e e soil damage and e osion.
5.5.5. Impac s on ma ine habi a s
As he mos widesp ead and abundan ma ine in ade s [My ilus gallop o incialis (Medi e anean mussel),
Semimy ilus algosus (paci i c mussel) and Balanus glandula (Paci i c ba nacle)] occu on ocky sho es, his habi a
is conside ed o be highly impac ed. These impac s a e ocused on he wes and sou h coas s whe e hese
species occu , and ocky sho es along he eas coas a e no a ec ed in he same way. Because o he impac s
associa ed wi h Ficopoma us enigma icus (es ua ine ube-wo m) in es ua ies, his habi a is conside ed o be
mode a ely impac ed, while ha bou en i onmen s expe ience low impac s. These esul s should be ca e ully
conside ed because hey ep esen he impac s o only 14% o ma ine alien species. These es ima es migh
change once impac s o mo e species a e unde s ood.
5.6. SYNTHESIS AND INDICATOR VALUES
The e a e ela i ely eliable da a on species ichness o in asi e plan s a na ional, p o incial and biome scales.
While some conse a ion agencies ha e p o ided in o ma ion abou he ex en o which p o ec ed a eas unde
hei managemen ha e been in aded by alien species, he e has no been any consis en moni o ing o alien
species wi hin a s anda dised se o spa ial uni s in Sou h A ica, despi e he exis ence o se e al a emp s o map
he ex en o in asions (Box 5.1). I is s ill no possible o p o ide es ima es o Rela i e in asi e abundance o mos
a eas (e.g. Van Wilgen e al., 2016).
Es ima ing he le el o in asion by alien species in pa icula a eas could only be made wi h a low deg ee o
ce ain y, gi en he ela i e lack o eliable and comp ehensi e da a on in asi e species. E en a he scale o
p o ec ed a eas, in o ma ion on he le el o in asions is a bes sca e ed and incomple e. Only Sou h A ican
Na ional Pa ks and wo o he nine p o incial conse a ion agencies (Cape Na u e and Ezem elo KwaZulu-Na al
Wildli e) we e able o p o ide lis s o in asi e species in p o ec ed a eas unde hei ju isdic ion, despi e a long-
s anding legal equi emen o de elop such lis s (Box 5.2). The le el o comple eness o hese lis s also a ies.
86
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
The e a e ew da a on impac s. Howe e , based on he exis ing s udies, i appea s ha impac s a e signi i can (in
pa icula on wa e esou ces), a e se o g ow apidly as in asi e species en e a phase o exponen ial g ow h,
and he widesp ead nega i e impac s cu en ly obse ed a e a small ac ion o wha hey will be i in asions
we e le unchecked.
TABLE 5.6 Indica o s used o epo ing on he s a us o in aded a eas. Fo ull de ails o how o calcula e he indica o s, see
Appendix 1.
INDICATOR METRIC
BASIC ADVANCED
LEVEL OF
CONFIDENCE NOTES
9. Alien species
ichness
9.1. In asi e species
ichness: Be ween
177 and 577 in asi e
species pe p o ince
9.2. In asi e
animal species
ichness: 46–162
pe hal -deg ee-
g id cell;
In asi e bi d
species ichness:
0–6 pe QDGC;
In asi e plan
species ichness:
0–165 pe QDGC
9.3. Numbe o
alien species a
di e en
in oduc ion
s ages pe
i ne -deg ee
na ional
subdi ision:
Da a no a ailable
9.1. Mode a e
9.2. Low o
animals;
mode a e o
bi ds and
plan s
10. Rela i e alien
species
ichness
10.1. Rela i e in asi e plan
species ichness pe p o ince
anged om 7% in he No he n
Cape P o ince o 25% in he
No hwes P o ince; no da a o
o he axa
10.2. Richness o alien
species o indigenous species
a di e en in oduc ion
s ages pe i ne -deg ee
na ional subdi ision:
Da a no a ailable
Low Dis ibu ion da a
o indigenous
species a e
incomple e
11. Rela i e
in asi e
abundance
11.1. Rela i e abundance in b oad
ca ego ies:
No da a
11.2. P opo ion o
abundance due o in asi e
species:
No da a
N/A Abundance da a
a e no a ailable
o ei he alien o
indigenous axa
12. Impac o
in asions
12.1
Fynbos: majo ,
massi e and mode a e
impac s on wa e
esou ces, angeland
p oduc i i y and
biodi e si y in ac ness
espec i ely
G assland: mode a e
and mino impac s on
wa e esou ces, and
angeland p oduc i i y
espec i ely
Sa anna: Mino
impac s on wa e
esou ces
12.2. Su ace
wa e uno
educed by
be ween 1 and
321 million m3 pe
p ima y ca chmen
Range p oduc i i y
educ ions a e
be ween 200 and
74500 la ge
li es ock uni s pe
yea pe e es ial
biome.
Biodi e si y
in ac ness educed
by be ween 0 and
3% pe biome
12.3. Es ima ed
annual losses due
o impac s on
wa e esou ces,
angeland
p oduc i i y and
biodi e si y
amoun o ZAR
5864, 337 and 428
million
espec i ely.
Low Es ima es based on
Van Wilgen e al.
(2008) o 12.1 and
12.2, and on De
Lange & Van Wilgen
(2010) o 12.3
C. Pe cen o a ea
expe iencing
majo impac s
C. 1.4% Low Based on he only
a ailable es ima e
o dense
(“condensed”)
co e in asi e
alien plan s in
Sou h A ica
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CHAPTER 6
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THE EFFECTIVENESS OF CONTROL MEASURES
TABLE 6.1 Sou ces o da a used o assign alues o indica o s o con ol e ec i eness, wi h le els o con i dence based on he
comple eness and accu acy o da a se s. The numbe ing o indica o s is based on Chap e 2. Indica o s a e: 14. Money spen ;
15. Planning co e age; 16. Pa hways ea ed; 17. Species ea ed; 18. A ea ea ed; 20. E ec i eness o species ea men s;
21.E ec i eness o a ea ea men s.
DESCRIPTION SOURCE SCALE
LEVEL OF
CONFIDENCE BASED
ON COMPLETENESS
AND ACCURACY
INDICATORS
INFORMED BY
THESE DATA
Moni o ing eco ds om o mal
e adica ion p ojec s
Sou h A ican Na ional
Biodi e si y Ins i u e
Na ional High 14,17
Es ima es o he e ec i eness o
biological con ol agen s in
disc e e ca ego ies (comple e,
subs an ial, negligible o no
assessed)
Regula e iews o
in asi e alien plan
biological con ol
(Mo an, Ho mann &
Hill 2011)
Na ional High 17, 20
Desc ip ions o in asi e species
managemen p og ams
Published scien i i c
li e a u e
Na ional Mode a e 15
Spa ial da abase o alien plan
con ol p ojec s, wi h
in o ma ion on species, a ea
ea ed and cos s (da a used in
mos esea ch p ojec s
assessing con ol e ec i eness)
Depa men o
En i onmen al A ai s,
Wo king o Wa e
In o ma ion
Managemen Sys em
(WIMS)
Na ional Low 14, 17, 18
Reco ds o e ec i eness o alien
eshwa e i sh con ol p ojec s
Cape Na u e and Sou h
A ican Ins i u e o
Aqua ic Biodi e si y
Ri e sys em (only one o
da e, see Wood o d e al.,
2017).
High 17, 20
Moni o ing o e al pig con ol
p og amme
Cape Na u e Localised Mode a e 17, 20
Desc ip ion o p ojec o
emo e alien og species (De
Villie s e al., 2016)
Published scien i i c
li e a u e
Localised Mode a e 17, 20
A ange o s udies assessing he
e ec i eness o alien plan
con ol measu es applied o
pa icula a eas
Published scien i i c
li e a u e
S udies we e ca ied ou a
he scale o p o inces,
ca chmen s, p o ec ed a eas
o p i a ely-owned a ms.
Mode a e 14, 17, 18, 20,
21
A ange o s udies assessing he
e u ns on in es men om alien
plan con ol p ojec s applied o
pa icula a eas o species
Published scien i i c
li e a u e
Limi ed o he ange o he
a ge species o biological
con ol; O he s udies a
p o incial o ca chmen scales
Low 14, 20, 21
In e cep ions a O.R. Tambo
In e na ional Ai po
Reco ds wi hin he
Depa men o
En i onmen al A ai s
A single en y poin Mode a e 16

94
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
6.2. PATHWAY-RELATED CONTROL MEASURES
Pa hway-based con ol measu es ocus on educing he isk o in oducing damaging species (i.e. he ac ual
mechanism by which species a i e, a he han speci i c species hemsel es). In in asion ecology, he e m
“dispe sal pa hways” is used b oadly, and e e s o he combina ion o p ocesses and oppo uni ies ha esul in
he mo emen o alien species om one place o ano he . Fo example, o ganisms can be in oduced by ships
h ough a numbe o pa hways (as s owaways in ballas wa e , in ca go con aine s, on he hull o he ship, o in
he luggage o c ew o passenge s).
In Sou h A ica, in en ional in oduc ions a e cu en ly managed h ough a pe mi ing sys em. Species equi e
impo pe mi s ha a e based on a isk assessmen conduc ed by a quali i ed isk assesso . These assessmen s a e
hen sen by he Depa men o En i onmen al A ai s (DEA) o he Alien Species Risk Analysis Re iew Panel
(ASRARP) o commen . ASRARP is a commi ee o expe s se up in Oc obe 2016 o p o ide scien i i c o e sigh
on decisions conce ning biological in asions, and in pa icula o p o ide ecommenda ions o DEA as o he
quali y and comple eness o an in asi e species isk assessmen . DEA hen makes a decision o app o e o ,
should he isks be oo high, ejec an applica ion o an impo pe mi . The e ec i eness o hese pe mi ing
measu es is co e ed in Chap e 7.
Fo ai a i c, inspec ions by he DEA a e cu en ly only ca ied ou a O.R. Tambo In e na ional Ai po , whe e
pe mi compliance is checked, illegal impo s a e in e cep ed and he luggage o ou is s and ca go is sea ched
o alien o ganisms ha may ha e been unin en ionally anspo ed as s owaways. Occasional and in equen
join ope a ions a e also ca ied ou by DEA in conjunc ion wi h o he depa men s a a limi ed numbe o o he
en y poin s.
Fo shipping, he Ma ine D a Ballas Wa e Bill aims o educe he isk o he unin en ional in oduc ion o alien
ma ine species h ough he elease o ballas wa e by ships. This legisla ion has no ye been passed.
While o he con ol measu es a e in place o manage addi ional pa hways o in oduc ion, hese ocus on
po en ial ag icul u al pes s (e.g. phy osani a y inspec ions a bo de pos s) o h ea s o human heal h (e.g.
sp aying he in e io o ai c a s o kill insec disease ec o s). In line wi h in e na ional obliga ions unde he
In e na ional Plan P o ec ion Con en ion (IPPC) and i s ole as he Na ional Plan P o ec ion O ganiza ion
(NPPO), he Depa men o Ag icul u e, Fo es y and Fishe ies (DAFF) egula es and moni o s he impo a ion o
ag icul u al goods. In e cep ions a e o en no eco ded o a e no en e ed in o a da abase, and such da abases
o en ocus only on qua an ine o ganisms.
Due o a lack o baseline da a, inc eases in global a el and ade, and changes in pa e ns o demand, i is ex emely
di i cul o demons a e a di ec link be ween con ol measu es and changes in a es o in oduc ion and
es ablishmen o alien species (Essl e al., 2015a). Fu he mo e, mos o he pa hway- ela ed con ol measu es in
Sou h A ica ha e no been in place o long enough o p ope ly assess hei e ec i eness. Fo example, inspec ions
a O.R. Tambo by he Biosecu i y Uni o he DEA only commenced in 2015, and cu en ly only ope a e on weekdays
du ing o i ce hou s (7:30-16:30). The e we e 24735 DEA inspec ions be ween Ap il 2015 and Janua y 2017 (346 o
comme cial ca go, none a he mail cen e and 24388 a he e minals), and en illegal impo s and luggage
s owaways we e in e cep ed. Illegal impo s can howe e en e he coun y almos unhinde ed h ough he
emaining 71 o mal po s o en y o a e wo king hou s and o e weekends a O.R. Tambo ai po . Howe e , o he
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CHAPTER 6
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THE EFFECTIVENESS OF CONTROL MEASURES
depa men s like DAFF and SARS-Cus oms a e p esen a o he po s o en y and some imes iden i y ins ances o
non-compliance and ale DEA biosecu i y. Finally, al hough many alien species ha e been acciden ally in oduced
o Sou h A ica (Faulkne e al., 2016a; see also Chap e 3), no managemen is in place o has been conside ed o
many o he pa hways h ough which hese alien species could en e he coun y. Fo example, ehicles (e.g. ca s
and ains) en e ing Sou h A ica a e no inspec ed o o ganisms anspo ed as s owaways, and no measu es a e
ye in place o p e en he in oduc ion o ma ine species a ached o he hulls o isi ing ships.
6.3. SPECIES-SPECIFIC CONTROL MEASURES
6.3.1. The s a us o a emp s a e adica ion
The e m “e adica e” is de i ned as he emo al o all indi iduals and p opagules om a speci i ed a ea ( o he
pu poses o his epo ei he he whole Sou h A ica o any one o he o sho e islands) whe e he likelihood o
e-colonisa ion is negligible, i.e. a success ul e adica ion will emo e he need o u u e con ol measu es. The
e ms “e adica e” o “e adica ion” a e o en inco ec ly used in policy documen s, con ol plans and legisla ion as
synonyms o “con ol” o “manage”. In his sec ion, he e ec i eness o e adica ion a emp s, whe e he goal o
e adica ion was explici ly s a ed, is assessed. Pluess e al. (2012) e iewed a global se o 136 e adica ion
campaigns agains 75 species (in asi e alien in e eb a es, plan s and plan pa hogens) and examined whe he
ce ain ac o s could explain success. They ound ha only he spa ial ex en o he in es a ion was signi i can ly
ela ed o he e adica ion ou come, and ha local campaigns we e mo e success ul han egional o na ional
campaigns; a ange o o he ac o s we e all un ela ed o e adica ion success. As a esul o hei i ndings, hey
ecommended ha e adica ion measu es should gene ally concen a e on incu sions when in es a ions a e s ill
ela i ely small, and he a iabili y in success is likely down o di e ence in he quali y o he p ojec managemen ,
including ac o s like moni o ing and epo ing.
Release o cap i e-b ed biological con ol agen s – Kim Wea e
96
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
I is also becoming inc easingly clea ha e adica ion measu es need o be conside ed ca e ully be o e hey a e
a emp ed, and ha once hey a e ini ia ed i is equally impo an ha p og ess should be moni o ed and
implemen a ion should no be subjec o he aga ies o unding cycles. In 2008, he Wo king o Wa e
P og amme unded he es ablishmen o Sou h A ican Na ional Biodi e si y Ins i u e’s In asi e Species
P og amme (SANBI ISP). SANBI ISP was designed o de ec and documen new in asions, and o p o ide he
c oss-ins i u ional coo dina ion needed o success ully implemen na ional e adica ion plans (Wilson e al.,
2013). The ocus o he uni was on species lis ed as ca ego y 1a unde he A&IS Regula ions, as well as on
selec ed non-lis ed species. Candida e non-lis ed species we e designa ed as ‘Species Unde Su eillance –
Possible E adica ion o Con ainmen Ta ge s’ (SUSPECT). The SUSPECT lis has no legal s a us, bu i includes
species whe e he e is su i cien documen ed e idence o wa an in-dep h in es iga ion and incu sion esponse.
New addi ions o he SUSPECT lis mus be accompanied by: (1) an ini ial isk assessmen , (2) a specimen lodged
in a Sou h A ican collec ion, (3) a sho backg ound dossie on li e- o m and in asi e endencies elsewhe e in
he wo ld, lodged wi h SANBI and (4) a de ailed p ojec plan including in o ma ion on cu en dis ibu ion in
Sou h A ica, local-scale dis ibu ion o one o mo e na u alised popula ions, an assessmen o managemen
op ions and an ou line o p oposed esea ch. This app oach has been ollowed since 2012, and as a esul a
numbe o SUSPECT species ha e been a ge ed o e adica ion (Table 6.2).
To da e, 42 e adica ion p ojec s ha e been ini ia ed, o a e unde conside a ion, in Sou h A ica (Table 6.2). Mos
o hese (32) a e aimed a e es ial o eshwa e plan s. O hese p ojec s, 23 a e unde conside a ion, pending
he ou come o a isk analysis o he de elopmen o a de ailed plan, and 10 a e ongoing [eigh agains plan s,
one a ge ing a bi d species (Co us splendens, he house c ow), and one a ge ing a mammal (Hemi agus
jemlahicus, he Himalayan ah ) Table 6.3]. O he comple ed his o ical p ojec s, h ee we e success ul (one being
he e adica ion o Felis ca us, he domes ic ca , om Ma ion Island, and he o he wo agains e es ial
in e eb a es). Six p ojec s we e deemed o ha e ailed, h ee agains plan s, one agains an amphibian, one
agains a eshwa e in e eb a e and one agains a e es ial in e eb a e.
TABLE 6.2 The s a us o e adica ion p ojec s in Sou h A ica. Fo species lis ed as in asi e unde he NEM:BA A&IS Regula ions
2016, ele an ca ego ies a e shown; unlis ed species a e also shown. SUSPECT species a e hose iden i i ed as ‘Species Unde
Su eillance – Possible E adica ion o Con ainmen Ta ge s’ (see ex ). The s a us o p ojec s is ei he “Unde conside a ion” (whe e
a decision o p oceed wi h e adica ion would depend on he ou come o a isk analysis o he de elopmen o a de ailed plan);
“ongoing” (whe e e adica ion a emp s a e unde way, bu whe e e adica ion has no ye been con i med); “ ailed” (whe e he
species has pe sis ed despi e e adica ion a emp s, such ha he e adica ion a emp was discon inued); o “success ul” (whe e he
species was e adica ed).
TAXON SPECIES AND CATEGORY PROJECT STATUS NOTES
Te es ial and
eshwa e plan s
Acacia i mb ia a
( inged wa le)
1a
Unde
conside a ion
Remo al o indi iduals om small popula ions
commenced in 2012
Te es ial and
eshwa e plan s
Acacia implexa
(sc ew pod wa le)
1a
Unde
conside a ion
Remo al o indi iduals om small popula ions
commenced in 2012 (Kaplan e al., 2012)
Te es ial and
eshwa e plan s
Acacia pa adoxa (kanga oo
ho n)
1a
Ongoing Remo al o popula ion on Table Moun ain
commenced in 2008 (Zenni e al., 2009). Cos o
da e ZAR 400000
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CHAPTER 6
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THE EFFECTIVENESS OF CONTROL MEASURES
TAXON SPECIES AND CATEGORY PROJECT STATUS NOTES
Te es ial and
eshwa e plan s
Acacia e inodes
(swamp wa le)
(SUSPECT)
Unde
conside a ion
Remo al o indi iduals om small popula ions
commenced in 2012
Te es ial and
eshwa e plan s
Acacia s ic a (hop wa le)
1a
Unde
conside a ion
Remo al o indi iduals om small popula ions
commenced in 2012 (Kaplan e al., 2014)
Te es ial and
eshwa e plan s
Acacia iscidula
(s icky wa le)
(SUSPECT)
Unde
conside a ion
Remo al o indi iduals om small popula ions
commenced in 2012
Te es ial and
eshwa e plan s
Alhagi mau o um
(camel ho n bush)
1b
Failed A emp ed e adica ion o camel ho n om
i iga ion schemes in 1960s
Te es ial and
eshwa e plan s
Anigozan hos l a idus
(yellow kanga oo paw)
(SUSPECT)
Unlis ed
Unde
conside a ion
Clea ing has s a ed bu p og ess has no been
assessed (Le Roux e al., 2010). Landowne has
exp essed u he in e es in con inua ion o his
wo k. New popula ions ound a sepa a e si e
on Agulhas Plain
Te es ial and
eshwa e plan s
Anigozan hos u us
( ed kanga oo paw)
(SUSPECT)
Unlis ed
Unde
conside a ion
Clea ing has s a ed bu p og ess has no been
assessed (Le Roux e al., 2010). Should possibly
deal wi h Anigozan hos l a idus and A. u us as a
single e adica ion a emp as he e is
hyb idisa ion. Ac i i ies ha e no sepa a ed he
wo species o hyb ids bu deal wi h hem as a
single a emp
In e eb a e Bac oce a in adens
(Asian ui l y)
1a
Failed Despi e epo s on he e adica ion o he Asian
ui l y om Limpopo P o ince in 2011
(Man akhan, Ven e & Ha ingh 2015) he
species is now widesp ead in he coun y
Te es ial and
eshwa e plan s
Banksia e ici olia
(hea h banksia) (SUSPECT)
Unde
conside a ion
A ew small popula ions in he Wes e n Cape
(Gee s e al., 2013b)
Te es ial and
eshwa e plan s
Be be is julianae
(Chinese ba be y)
Unlis ed
Unde
conside a ion
Small popula ions in No hwes , F ee S a e,
KwaZulu-Na al and Wes e n Cape; possibly
p esen in Leso ho (Kee , Cindi & Du P eez 2016)
Bi d Co us splendens
(house c ow)
1a
Ongoing The popula ion has been educed om 10000
bi ds in 2009 o less han 400 bi ds by end o
Janua y 2016 in Cape Town. The eThekwini
popula ion is cu en ly (2016) es ima ed a less
han 5 bi ds, and no bi ds ha e been eco ded
as seen in he las 9 mon hs
Te es ial and
eshwa e plan s
Epip emnum au eum
(de il’s i y)
(SUSPECT)
Unde
conside a ion
Small popula ions p esen in KwaZulu-Na al
(Moodley, P ocheş & Wilson 2017)
Mammal Felis ca us (domes ic ca )
1a (on islands)
Success ul E adica ion o ca s om Ma ion Island be ween
1973 and 1992 (Bes e e al., 2002)
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THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
TAXON SPECIES AND CATEGORY PROJECT STATUS NOTES
Te es ial and
eshwa e plan s
Fu c aea oe ida
(Mau i ian hemp)
1a
Unde
conside a ion
Sca e ed small popula ions in Wes e n and
Eas e n Cape, and KwaZulu-Na al. Hende son and
Wilson (2017) ecommend eclassi i ca ion as 1b
Te es ial and
eshwa e plan s
Genis a monspessulana
(Mon pellie b oom)
1a
Unde
conside a ion
Small popula ions p esen on he Cape
Peninsula (Gee s e al., 2013a)
Mammal Hemi agus jemlahicus
(Himalayan ah )
1b
Ongoing The e was an a emp ed e adica ion o he
Himalayan ah om Table Moun ain, bu
e adica ion uncon i med
Te es ial and
eshwa e plan s
Hyd illa e icilla a
(hyd illa)
1a
Ongoing Occu s in Pongolapoo Dam, on he bo de
be ween KwaZulu-Na al and Swaziland. Cos o
da e ZAR 800000.00 (including esea ch on
biological con ol) (Klein, 2011; Coe zee, Hill &
Schlange 2008)
Te es ial and
eshwa e plan s
Hyd ocleys nymphoides
(wa e poppy)
1a
Unde
conside a ion
Occu s a wo si es in KwaZulu-Na al (Nxumalo
e al., 2016)
Te es ial and
eshwa e plan s
Hype icum pseudohen yi
(Hen y’s S . John’s Wo )
Unlis ed
Unde
conside a ion
Se e al popula ions in KwaZulu-Na al
Te es ial and
eshwa e plan s
I is pseudaco us
(yellow l ag)
1a
Unde
conside a ion
Found a se e al si es in Gau eng and KwaZulu-
Na al (Jaca & Mkhize 2015). Cos o con ol o
da e ZAR 621000.00.
Te es ial and
eshwa e plan s
Ly h um salica ia
(pu ple looses i e)
1a
Ongoing Occu s along he Liesbeeck Ri e in he ci y o
Cape Town. Cos o con ol o da e ZAR
435000.00.
Te es ial and
eshwa e plan s
Melaleuca hype ici olia
( ed- l owe ing ea ee)
1a
Ongoing One popula ion on he Cape Peninsula. Clea ing
commenced in 2012 (Hickley e al., 2017)
Te es ial and
eshwa e plan s
Melaleuca pa is aminea
( ough-ba ked honey-my le)
(SUSPECT)
Unde
conside a ion
Small popula ions in he Wes e n Cape;
easibili y o e adica ion unde assessmen
(Jacobs, Richa dson & Wilson 2014)
Te es ial and
eshwa e plan s
Mimosa albida (common
name unknown)
Unlis ed
Unde
conside a ion
One small popula ion in KwaZulu-Na al
(Cheek 2015)
Te es ial and
eshwa e plan s
Opun ia au an iaca
(join ed cac us)
1b
Failed A emp ed e adica ion o join ed cac us in he
1930s and 1940s (Mo an & Annecke, 1979)
Te es ial and
eshwa e plan s
Opun ia salmiana
(bu cac us)
1a
Ongoing Small popula ion being managed owa ds
e adica ion in he No hwes P o ince.

99
CHAPTER 6
I
THE EFFECTIVENESS OF CONTROL MEASURES
TAXON SPECIES AND CATEGORY PROJECT STATUS NOTES
In e eb a e O ala punc a a
( eckled edible snail)
Unlis ed
Success ul E adica ion o he Medi e anean snail in he
Wes e n Cape be ween 1987 and 1989 a a cos o
ZAR 215000 (1988 p ices) (He be & Si gel 2001)
Te es ial and
eshwa e plan s
Pe i e ia alliacea
(Guinea hen-weed)
Unlis ed
Unde
conside a ion
Less han 1000 plan s in he ci y o Du ban
(Cheek 2013)
In e eb a e Polis es dominula
(Eu opean pape wasp)
1b
Unde
conside a ion
Dis ibu ion cu en ly limi ed o he Wes e n
Cape P o ince, whe e con ol is ongoing
(Benadé e al., 2014)
In e eb a e P ocamba us cla kii
( ed swamp c ay i sh)
P ohibi ed
Failed E adica ion was a emp ed in he C ocodile
Ri e , Mpumalanga in 1994, bu he species has
su i ed (Nunes e al., 2017)
Te es ial and
eshwa e plan s
Pue a ia mon ana
a . loba a
(kudzu ine)
1a
Ongoing Ea lie a emp ed e adica ion o kudzu ine in
Mpumalanga in he 1960s and 1970s ailed.
New a emp is being implemen ed by SANBI
(Gee s e al., 2016)
Te es ial and
eshwa e plan s
Sagi a ia la i olia
(common a owhead)
Unlis ed
Ongoing Nine o he known en popula ions ha e been
clea ed in KZN.
Te es ial and
eshwa e plan s
Sagi a ia pla yphylla
(del a a owhead)
1a
Unde
conside a ion
Sca e ed popula ions in ou p o inces
Amphibian Scle oph ys gu u alis
(A ican common oad)
Unlis ed
Failed A emp o ex i pa e he gu u al oad on he
Cape Peninsula (Vime ca i e al, 2017; Measey
e al., 2017)
Te es ial and
eshwa e plan s
Solanum elaeagni olium
(sil e -lea bi e apple)
1b
Failed A emp ed e adica ion o sa ansbos in he
No hwes P o ince be ween 1952 and 1972
Te es ial and
eshwa e plan s
Spa ina al e ni l o a
(smoo h co d g ass)
1a
Ongoing A emp ed e adica ion in he G oo B ak Es ua y
(Adams, Van Wyk & Riddin 2016; Riddin, Van Wyk
& Adams 2016)
Te es ial and
eshwa e plan s
Teph ocac us a icula us
(pine cone cac us)
1a
Unde
conside a ion
Popula ions in he No he n, Wes e n and
Eas e n Cape P o inces
Te es ial and
eshwa e plan s
T ipla is ame icana (an ee)
1a
Unde
conside a ion
Less han 1000 plan s in he ci y o Du ban
(Lala & I ey, 2011)
In e eb a e T ogode ma g ana ium
(khap a bee le)
1b
Success ul E adica ion o khap a bee le a mul iple si es,
mos ecen ly nea Uping on in 1972
In e eb a e Vespula ge manica
(Ge man wasp)
Unde
conside a ion
The geog aphical ange o he Ge man wasp is
now well documen ed and des uc i e
sampling has been ca ied ou since 2014
100
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
TABLE 6.3 Numbe o e adica ion p ojec s a emp ed pe high-le el axon in Sou h A ica, wi h assessmen o s a us
STATUS
TAXON
TOTAL
TERRESTRIAL
AND
FRESHWATER
PLANTS
MAMMALS BIRDS AMPHIBIANS
TERRESTRIAL
AND
FRESHWATER
INVERTEBRATES
Unde conside a ion 21 2 23
Ini ia ed and ongoing 8 1 1 10
Success ully e adica ed 1 2 3
Failed 3 1 2 6
To als 32 2 1 1 6 42
6.3.2. Biological con ol o in asi e plan s
O e iew o e ec i eness o biological con ol o alien plan s. Biological con ol o in asi e plan s using in oduced
na u al enemies has con ibu ed signi i can ly o sus ained, cos -e ec i e managemen o se e al in asi e plan
species in Sou h A ica. Biological con ol p og ammes ha e been launched o a e unde in es iga ion o 77
in asi e plan species. Many o he mos ob ious successes ha e been agains acacias, cac i (Figu e 6.1) and
in asi e aqua ic plan s, al hough successes ha e ce ainly no been limi ed o hese g oups. Hende son & Wilson
(2017), in a e iew based on eco ds in he Sou he n A ican Plan In ade s A las, concluded ha “some [in asi e
plan ] species which ha e been he subjec s o success ul biological con ol p og ammes ha e shown e y li le
expansion in hei dis ibu ion” and “in gene al success ul biological con ol seems o be associa ed wi h a
educ ion in he a e o sp ead”. This is in s a k con as o species ha ha e no been subjec ed o any biological
con ol, whe e sp ead has accele a ed in many cases.
FIGURE 6.1 Cylind opun ia ulgida (chain- ui cholla) in he No he n Cape P o ince. The igh -hand panel shows he popula ion
a e he in oduc ion o he biological con ol agen Dac ylopius omen osus (cholla bio ype, cochineal cladode sucke ).
In asi e plan species ha a e unde biological con ol. Biological con ol agen s ha e been es ablished on 60
in asi e plan species in Sou h A ica (Table 6.4). O hese, 15 species (eigh succulen cac i, ou aqua ic plan s,
wo he bs and one sh ub species) a e unde comple e con ol; 19 species (nine ee o sh ub species, eigh
succulen cac i, one aqua ic plan and one he b) a e unde a subs an ial deg ee o con ol; a negligible deg ee o
con ol has been achie ed on 15 species (11 ee o sh ub species, wo he bs and wo climbe s); while he
deg ee o con ol has no been de e mined o he emainde ( h ee ee and sh ub species, ou succulen cac i,
wo he bs and wo climbe s).
101
CHAPTER 6
I
THE EFFECTIVENESS OF CONTROL MEASURES
TABLE 6.4 In asi e plan species on which biological con ol agen s ha e been success ully es ablished in Sou h A ica, and he
deg ee o biological con ol achie ed as pe he ollowing ca ego ies: Comple e: no o he con ol measu es a e needed o educe he
in asi e plan species o accep able le els, a leas in a eas whe e he agen s a e es ablished; Subs an ial: o he me hods a e needed
o educe he in asi e plan species o accep able le els, bu less e o is equi ed (e.g. less equen he bicide applica ions o less
he bicide needed pe uni a ea); Negligible: in spi e o damage in l ic ed by he agen s, con ol o he in asi e plan species emains
en i ely elian on he implemen a ion o o he con ol measu es; and No de e mined: ei he he elease o he agen s has been oo
ecen o meaning ul e alua ion o he p og amme has no been e alua ed.
INVASIVE PLANT SPECIES LIFE FORM REGION OF ORIGIN DEGREE OF
BIOLOGICAL CONTROL
Acacia baileyana (Bailey’s wa le) T ee Aus alia Negligible
Acacia cyclops ( ooik ans) Tall sh ub o ee Aus alia Subs an ial
Acacia dealba a (sil e wa le) T ee Aus alia Negligible
Acacia decu ens (g een wa le) T ee Aus alia Negligible
Acacia longi olia (long-lea ed wa le) T ee Aus alia Subs an ial
Acacia mea nsii (black wa le) T ee Aus alia Subs an ial
Acacia melanoxylon (Aus alian blackwood) T ee Aus alia Subs an ial
Acacia podaly ii olia (pea l acacia) T ee Aus alia Negligible
Acacia pycnan ha (golden wa le) T ee Aus alia Subs an ial
Acacia saligna (Po Jackson) T ee Aus alia Subs an ial
Age a ina adenopho a (C o on weed) Pe ennial he b Cen al Ame ica Negligible
Age a ina ipa ia (mis l owe ) Pe ennial he b Cen al Ame ica Comple e
Aus ocylind opun ia subula a (long spine
cac us)
Succulen sh ub Sou h Ame ica No de e mined
Azolla i liculoides (Azolla) F ee- l oa ing aqua ic plan Sou h Ame ica Comple e
Caesalpinia decape ala (Mau i ius ho n) Tho ny e e g een sh ub
o climbe
Asia Negligible
Campuloclinium mac ocephalum (pompom
weed)
Sh ub Sou h Ame ica No de e mined
Ca diospe mum g andi l o um
(balloon ine)
Pe ennial sligh ly woody
climbe
Sou h Ame ica No de e mined
Ce eus hildmannianus (queen o he nigh ) Spiny succulen ee Sou h Ame ica Comple e
Ce eus jamaca u (queen o he nigh ) Spiny succulen ee Sou h Ame ica Comple e
Ch omolaena odo a a ( i i d weed) Sh ub No h, Cen al & Sou h
Ame ica
No de e mined
Ci sium ulga e (spea his le) Spiny he baceous biennial Eu ope Negligible
Cylind opun ia ulgida (chain- ui cholla) Compac spiny succulen
sh ub
No h & Cen al Ame ica Comple e
Cylind opun ia ulgida a . mamilla a
(boxing-glo e cac us)
Compac spiny succulen
sh ub
Sou h Ame ica Comple e
Cylind opun ia imb ica a (imb ica e cac us) Spiny succulen sh ub No h & Cen al Ame ica Subs an ial
Cylind opun ia lep ocaulis (pencil cac us) Compac spiny succulen
sh ub
No h & Cen al Ame ica Comple e
Dolichand a unguis-ca i (ca ’s claw c eepe ) Woody-s emmed climbe Cen al & Sou h Ame ica Negligible
Eichho nia c assipes (wa e hyacin h) F ee- l oa ing aqua ic he b Sou h Ame ica Subs an ial
Gledi sia iacan hos (honey locus ) Sp eading ee No h Ame ica No de e mined
102
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
INVASIVE PLANT SPECIES LIFE FORM REGION OF ORIGIN DEGREE OF
BIOLOGICAL CONTROL
Hakea gibbosa ( ock hakea) Tall sh ub Aus alia Negligible
Hakea se icea (silky hakea) Tall sh ub Aus alia Subs an ial
Ha isia balansae (s angle p ickly apple) Spiny succulen sh ub Sou h Ame ica Subs an ial
Ha isia ma inii (moon cac us) Spiny succulen sh ub Sou h Ame ica Comple e
Ha isia pomanensis (midnigh lady) Spiny succulen sh ub Sou h Ame ica Subs an ial
Ha isia o uosa (spiny snake cac us) Spiny succulen sh ub Sou h Ame ica Subs an ial
Hyloce eus unda us (nigh -blooming ce eus) Vine-like cac us T opical Ame ica No de e mined
Hype icum pe o a um (S John’s wo ) Pe ennial he b Eu ope & Asia Comple e
Lan ana cama a (lan ana) Sh ub Cen al & Sou h Ame ica Negligible (High eld)
o subs an ial (coas al
& Low eld)
Lep ospe mum lae iga um
(Aus alian my le)
Tall sh ub o ee Aus alia Negligible
Leucaena leucocephala (leucaena) Sh ub o small ee T opical Ame ica Negligible
My iophyllum aqua icum
(pa o ’s ea he )
Roo ed aqua ic he b Sou h Ame ica Comple e
Opun ia au an iaca (join ed cac us) Spiny succulen sh uble Sou h Ame ica Subs an ial
Opun ia engelmannii (small ound-lea ed
p ickly pea )
Succulen sh ub No h & Cen al Ame ica Negligible
Opun ia i cus-indica (mission p ickly pea ) Succulen ee o sh ub Cen al Ame ica Subs an ial
Opun ia humi usa (la ge- l owe ed
p ickly pea )
Succulen low sh uble No h Ame ica Comple e
Opun ia monacan ha (d ooping
p ickly pea )
Succulen sh ub o ee Sou h Ame ica Comple e
Opun ia salmiana (bu cac us) Succulen sh ub Sou h Ame ica Subs an ial
Opun ia spinuli e a (la ge ound-lea ed
p ickly pea )
Succulen sh ub Cen al Ame ica No de e mined
Opun ia s ic a (Aus alian pes pea ) Spiny succulen sh ub No h Ame ica & Ca ibbean Subs an ial
Pa ase ian hes lophan ha (s ink bean) T ee Aus alia Subs an ial
Pa henium hys e opho us ( amine weed) Annual sh ub Ca ibbean No de e mined
Penioce eus se pen inus (se pen cac us) Succulen sh ub Mexico No de e mined
Pe eskia aculea a (Ba bados goosebe y) Spiny sh ubby o
clambe ing ine
Sou h Ame ica & Ca ibbean No de e mined
Pis ia s a io es (wa e le uce) F ee- l oa ing aqua ic he b Sou h Ame ica Comple e
P osopis species (mesqui e) T ee No h & Cen al Ame ica Negligible
Sal inia moles a (wa e e n) F ee- l oa ing aqua ic e n Sou h Ame ica Comple e
Sesbania punicea ( ed sesbania) Sh ub Sou h Ame ica Comple e
Solanum elaeagni olium (sil e lea
bi e apple)
He baceous sh uble No h, Cen al & Sou h
Ame ica
Subs an ial
Solanum mau i ianum (bugweed) T ee Sou h Ame ica Negligible
Solanum sysimb ii olium (wild oma o) Spiny low sh ub Sou h Ame ica Subs an ial
Tecoma s ans (yellow bells) T ee No h & Cen al Ame ica No de e mined
109
CHAPTER 6
I
THE EFFECTIVENESS OF CONTROL MEASURES
6.4.2. Assessmen s o con ol e ec i eness a i ne scales whe e in o ma ion is a ailable
The e ec i eness o con ol measu es in a pa icula a ea ( o example a p o ec ed a ea, a ca chmen a ea, a a m,
o a s e ch o i e ) would need o be assessed agains he in ended goals o he measu e. In addi ion, he
assessmen should be based on egula moni o ing o ou comes. Almos all a ea-based con ol measu es a e
aimed a alien plan species, and mos ha e he goal o eaching a “main enance le el”, al hough his goal is
seldom explici ly s a ed (Van Wilgen e al., 2016a; Fill e al., 2017). The concep o a main enance le el ecognises
ha , o many in asions, e adica ion is in easible, bu ha hey can be educed o a le el whe e he nega i e
impac s a e negligible and con ol cos s a e ela i ely low in pe pe ui y. This was de i ned by Goodall & Naude
(1998) as “ he sys ema ic educ ion o he majo in asi e alien plan species in de i ned ac s o land o a le el
whe e hey no longe p esen a p oblem”. In Sou h A ica, as in many o he pa s o he wo ld, he in ended goals
o con ol measu es a e p edominan ly no explici . In he as majo i y o Sou h A ica’s go e nmen - unded
alien plan con ol p ojec s, he indica o s used o moni o p og ess and se a ge s include he amoun s o
money o be spen , he numbe o people o be employed, and he a eas o be ea ed. These a e inpu o ou pu
indica o s, a he han ou comes in e ms o changes in he le els o plan in asions. In he absence o a
moni o ing p og amme ha is ocussed on ou comes, i is di i cul o assess e ec i eness objec i ely. Howe e ,
se e al s udies ha e been conduc ed, pa icula ly o e he pas decade, in which he e ec i eness o managemen
has been assessed, and hese a e p esen ed and summa ised he e in ch onological o de . These s udies p o ide
a limi ed basis om which o de i e b oad conclusions abou he e ec i eness o con ol measu es.
Alien plan con ol in he Cape o Good Hope Na u e Rese e, Wes e n Cape P o ince, 1941-1987 (Macdonald, Cla k &
Taylo 1989). The Cape o Good Hope Na u e Rese e is a ynbos sh ubland a ea now inco po a ed in o he Table
Moun ain Na ional Pa k. I was his o ically hea ily in aded by alien ees and sh ubs, and con ol ope a ions s a ed
in 1943. These p o ed o be almos o ally ine ec i e o a leas he i s 35 yea s; no sys ema ic con ol s a egy
was implemen ed, ollow-up and con ol was inadequa e o p e en e-es ablishmen o elled hicke s and he
supe ision o con ol eams was de i cien . Linkage o con ol ope a ions o i ewood p oduc ion was a signi i can
ac o in his ailu e. In 1974 a 10-yea con ol s a egy was d awn up and la e began o be e ec i ely implemen ed.
Su eys o 40 plo s in he cen e o he ese e in 1966, 1976–1980 and 1986 showed inc easing densi ies o
species o he han he easily con olled P. pinas e up o 1976–1980. Since hen almos all indi idual alien plan s
alle han 1.8 m in heigh we e elimina ed and indica ions om smalle heigh classes a e ha seed banks we e
deple ed. This s udy p o ided an ea ly indica ion o he alue o a s a egic app oach o alien plan con ol.
Managemen o P osopis species (mesqui e) in he No he n Cape P o ince (Van den Be g, 2010; Wise, Van Wilgen
&Le Mai e, 2012; Van Wilgen e al., 2012). T ees in he genus P osopis (mesqui e) we e in oduced o p o ide a
sou ce o odde o li es ock in he a id a eas o Sou h A ica. They la e became in asi e, sp eading o e la ge
a eas and causing many nega i e impac s. His o ical es ima es o he a e o sp ead o P osopis ees in Sou h
A ica anged om 3.5 o 18% pe yea , which implied ha he in aded a ea could double e e y 5 o 8 yea s. In
he No he n Cape, he es ima ed o al in aded a ea inc eased by almos a million
hec a es be ween 2002 and 2007, which is equi alen o 27.5% pe yea , and his
occu ed a a ime du ing which ZAR 390 million (2012 alues) was spen on
con ol. O e all, i was concluded ha es ima ed con ol cos s would exceed he
i nancial capabili ies o Public Wo ks p og ammes, and ha mo e e ec i e con ol
me hods, such as biological con ol, would be needed o p e en subs an ial
INPUTS TO
CONTROL
The amoun spen
by he DEA pe
yea on con ol
ope a ions is
a leas
R1.5
BILLION

110
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
economic losses. A mo e ecen upda e (R.T. Shackle on unpublished da a) ound ha he public wo ks clea ing
p ojec s had ea ed 203000 ha o he a ea in aded by P osopis be ween 2000 and 2015 (clea ing consis ed o
an ini ial clea ing and h ee ollow-up clea ings, on a e age, o emo e seedlings). The cos o hese measu es
amoun ed o ZAR 1.8 billion (R 4.2 billion exp essed in 2016- alue ZAR, o o e ZAR 2000/ha ea ed) o e he
same pe iod. The p ojec s a ed in 1995, bu cos es ima es p io o he yea 2000 a e no a ailable. These i gu es
also excluded he cos o esea ching and in oducing he h ee biological con ol agen s, as well as p i a e
landowne con ol cos s which a e ages a ound ZAR 21000 pe a m pe yea (Shackle on, Le Mai e & Richa dson
2015). Be ween 2000 and 2016, P osopis glandulosa, and P osopis hyb ids inc eased hei ange om 40 o 112,
and 390 o 481 qua e -deg ee g id cells, inc eases o 50 and 180% espec i ely (Hende son & Wilson, 2017),
sugges ing ha subs an ial con ol measu es we e doing li le o s op he sp ead o his damaging species.
Cos -e ec i eness o alien plan clea ing in he K om and Kouga Ri e ca chmen s, Eas e n Cape P o ince
(McConnachie e al., 2012). This assessmen was ca ied ou in he K om (1556 km2) and Kouga (2426 km2)
ca chmen s in he Eas e n Cape P o ince. I concluded ha he cos o clea in aded land was 2.4 imes highe
han he highes equi alen es ima e made elsewhe e in Sou h A ica. A a es o clea ing a he ime o he
s udy, i would ha e aken be ween 54 and 695 yea s o clea he ca chmen s, in he K om and Kouga, espec i ely,
assuming no u he sp ead. By aking ongoing sp ead in o accoun , i was appa en ha cu en con ol
measu es would be inadequa e, and in asions would mos likely con inue o sp ead in he ca chmen s. The
s udy also ound signi i can ine i ciencies in he o m o inaccu a e eco ds, whe e 25% o he a eas eco ded as
ha ing been clea ed had in ac no been clea ed.
His o ical cos s and u u e scena ios o alien plan con ol in p o ec ed a eas in he Cape Flo is ic Region (Van Wilgen e
al., 2016). This s udy sough o documen he ex en and cos s o subs an ial con ol e o s in he Cape Flo is ic
Region (CFR) o e he pas wo decades, and o es ima e he esou ces ha would be needed o educe he
p oblem o a “main enance le el” a which i could be sus ainably con ained in pe pe ui y. His o ical cos s o
con ol in CFR p o ec ed a eas be ween 1996 and 2015 amoun ed o ZAR 564 million (2015 alues). P edic ing
u u e con ol e ec i eness equi ed a numbe o assump ions o be made abou he u u e unding le els, a es
o sp ead, and he e o ha would be equi ed o b ing alien plan s down o a main enance le el. The s udy
concluded ha , o scena ios in which con ol measu es con inued agains all in asi e plan species, he es ima ed
equi ed unding o achie e he goal o educing in asions o a manageable le el was up o 4.6 imes g ea e han
he amoun spen o e he pas 20 yea s. Unde many plausible u u e scena ios ( o example 8% sp ead and
cu en o educed unding) he in aded a ea would con inue o g ow, despi e signi i can ongoing spending.
E ec i eness o alien plan clea ing in he Be g Ri e ca chmen in he Wes e n Cape P o ince (Fill e al., 2017). This
s udy assessed alien plan (mainly Pinus and Acacia) con ol ac i i ies in he Be g Ri e ca chmen in he Wes e n
Cape P o ince. Con ol ope a ions ook place o e 13 yea s, a a cos o ZAR 50 million (ne p esen alue in 2015
ZAR), and succeeded in g ea ly educing he co e o alien plan s, bu no o a main enance le el. A he ime o
assessmen , o e 1000 ha s ill suppo ed dense o medium in asions (> 25% co e ), and he a ea occupied by
sca e ed Pinus plan s had inc eased by o e 3000 ha o >5700 ha (Figu e 6.2). While he p ojec is ongoing, i
was concluded ha he en i e a ea would e e o a mo e densely-in aded s a e in he e en o a educ ion o
unding, gi en ha a signi i can popula ion o in asi e plan s o all species emained p esen in ai ly la ge
numbe s. The s udy poin ed o se e al ac o s ha had con ibu ed o ine i ciencies, including he lack o a plan,
a ailu e o in eg a e p esc ibed bu ning and mechanical clea ing, a ailu e o co-o dina e high-al i ude clea ing
wi h o he ope a ions, and he use o ( ela i ely ine i cien ) hand ools ins ead o powe ools.
111
CHAPTER 6
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THE EFFECTIVENESS OF CONTROL MEASURES
Pinus
Dense Medium Low Sca e ed
2001 2014
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
A ea (ha)
Acacia
Dense Medium Low Sca e ed
2001 2014
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
A ea (ha)
FIGURE 6.2 A ea occupied by alien Pinus and Acacia ees a di e en le els o co e in he uppe Be g Ri e ca chmen a
he ini ia ion o a con ol p ojec in 2001, and a e 13 yea s o ea men s in 2014. Co e le els a e dense (> 50% co e ), medium
(26–50% co e ), low (6–25% co e ) and sca e ed (0.5–5.0% co e ). Figu e ed awn om Fill e al. (2017).
Alien plan con ol p ojec s in he Hawequas Moun ain complex in he Wes e n Cape P o ince (McConnachie e al.,
2016). This s udy ook place in he Hawequas Moun ain Fynbos complex, an a ea co e ing 1451 km2 in he
sou h-wes e n pa o he Wes e n Cape P o ince. The a ea had been subjec ed o alien plan con ol ope a ions
o e se e al yea s, including he emo al o abandoned pine plan a ions. Con ol educed co e – i was
es ima ed ha he p opo ion o he a ea co e ed by in asi e ees would ha e been almos 50% highe had
he e been no con ol. Howe e , he cos s we e h ee o i e imes highe han he p edic ions made when he
p og amme was ini ia ed. I was concluded ha con ol migh ha e p e en ed a la ge a ea om being in aded,
i i had ocussed all o i s e o on un ans o med land and no on abandoned plan a ions.
E i ciency o in asi e alien plan managemen in he Ga den Rou e Na ional Pa k (GRNP), Wes e n and Eas e n Cape
P o ince (K aaij e al., 2017). The GRNP is si ua ed along he sou he n Cape coas o Sou h A ica be ween he
Indian Ocean in he sou h and he wa e shed o he Ou eniqua and Tsi sikamma Moun ains in he no h,
ex ending o e 152500 ha o which ~78 000 ha comp ises i e-p one ynbos sh ublands and ~41500 ha
comp ises A o empe a e o es . The ynbos a eas we e subs an ially in aded by ees and sh ubs in he gene a
Acacia, Hakea and Pinus. In asi e alien plan con ol ope a ions had been ac i e in he pa k since 1995. The s udy
se ou o assess he e i ciency o alien plan managemen p ac ices in he i eld. Pa s o he GRNP ha e a long
his o y o alien plan con ol ope a ions, bu comp ehensi e s a egic planning, p io i isa ion and imp o ed
moni o ing had only ecen ly been ini ia ed. The s udy sough o in es iga e he alignmen o implemen a ion
wi h managemen plans, and he e ec i eness o alien plan clea ing p ac ices in he i eld. The s udy ound ha ,
al hough de ailed managemen plans we e de eloped, implemen a ion was poo ly aligned wi h plans. The
quali y o many ea men s was ound o be inadequa e, wi h wo k done o s anda d in only 23% o he assessed
a ea. P oblems encoun e ed included a comple e absence o ea men applica ion despi e paymen o
con ac o s (33% o assessed a ea); pa ial ea men o a eas (38%), species (11%) o age classes (8%), lea ing
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THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
o he s un ea ed; use o inapp op ia e ea men me hods (9%); and ailu e o adhe e o ea men s anda ds
(7%). Acco dingly, successi e ollow-up ea men s la gely did no educe he co e o in asi e plan s. Field
su eys and clea ing eco ds sugges ed ha inaccu a e (o lack o ) in i eld es ima ion o co e p io o con ac
gene a ion esul ed in an e oneous es ima ion o e o equi ed, and expendi u e dispa a e wi h equi ed
no ms. This s udy poin s o subs an ial ine i ciencies in he applica ion o con ol me hods, and iden i i ed he
need o igo ous, compulso y, in i eld assessmen o in asi e plan co e p io o con ac alloca ion and
assessmen o he quali y o ea men s applied p io o paymen o con ac o s.
Managing in asi e plan s on Ve gelegen Wine Es a es in he Wes e n Cape P o ince (Van Rensbu g, Richa dson &
Van Wilgen 2017). This s udy ook place on he p i a ely-owned Ve gelegen Es a e (5332 ha) in he Ho en o s
Holland Moun ain Range Basin nea he own o Some se Wes in he Wes e n Cape. The a ea had become
subs an ially in aded by ees and sh ubs in he gene a Acacia, Hakea and Pinus. In asi e plan con ol ope a ions
commenced in 2004, and he s udy assessed hei cos and e ec i eness o e mo e han a decade. The
assessmen showed ha he co e o dense in asi e plan s declined by 70% o e he 10 yea s since managemen
ope a ions began (Table 6.3), bu ha ope a ions cos 3.6 imes mo e han was o iginally es ima ed (ZAR 43.6 s
12.19 million espec i ely). The challenges associa ed wi h managing in asi e plan s on p i a e land we e e y
simila o hose aced on s a e-owned land, wi h he e i ciency o managemen being cons ained by mul iple
in e ac ing en i onmen al and socio-economic ac o s. Howe e , some success in managing he in asions was
achie ed by adhe ing o bes p ac ice app oaches, including ca e ul planning wi h clea achie able goals in
mind, a commi men o s able long- e m unding, and egula moni o ing.
Closed Dense Medium Sca e ed Ve y Sca e ed Occasional
A ea (ha)
2004 2015
00
500
1000
1500
2000
2500
3000
3500
FIGURE 6.3 A ea occupied by in asi e plan s in six co e classes a Ve gelegen Wine Es a es in 2004 and 2015. The classes a e
occasional (< 1% co e ); e y sca e ed (1–5% co e ); sca e ed (5–25% co e ); medium (25–50% co e ); dense (50–75% co e );
and closed (> 75% co e ). Figu e ed awn om Van Rensbu g, Richa dson & Van Wilgen (2017).
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THE EFFECTIVENESS OF CONTROL MEASURES
Alien plan con ol and ecosys em eco e y along he Rondega Ri e in he Wes e n Cape P o ince “(Fill, K i zinge -
Kloppe & Van Wilgen 2017). The s udy ook place along he Rondega Ri e , which l ows in a no h-wes e ly
di ec ion o 28 km om i s sou ce in he Cede be g Wilde ness A ea o i s con l uence wi h he Oli an s Ri e a
he Clanwilliam Dam. The i e was in aded by dense s ands o alien ees, mainly black wa le (Acacia mea nsii),
blackwood (Acacia melanoxylon) and gum ees (Eucalyp us g andis). A p ojec o clea hese in asi e species was
ini ia ed in 2013. The s udy aimed o e iew he land-use p ac ices bo h on he p ojec si e and on adjacen
a eas, and examine how hey could a ec he p ojec ’s success o e he long e m. The assessmen e ealed
eco e y o indigenous ipa ian sh ubs a e clea ing o dense s ands o Acacia mea nsii, bu also ha g asses
became dominan on clea ed si es and in pas u es. This s udy concluded ha seconda y in asions, especially by
g asses, can ha e s ong e ec s on ecosys em dynamics and ha achie ing he goals o es o a ion may he e o e
equi e addi ional ac i e managemen .
In asi e plan con ol in he K uge Na ional Pa k (KNP), Mpumalanga and Limpopo P o inces (Van Wilgen e al.,
2017). The KNP is one o ew p o ec ed a eas in Sou h A ica ha has had a long his o y o con olling in asi e
species, pa icula ly plan s. A emp s o con ol alien plan s in he KNP began in he mid-1950s, and expanded
subs an ially in he la e 1990s. The s udy sough o documen he goals o alien plan managemen and he
plans o achie ing hem; o iden i y he species a ge ed o con ol and he his o ical cos s o hei managemen ;
and o documen and assess he e ec i eness o he managemen in e en ions. This assessmen epo ed ha
o e ZAR 300 million had been spen on con ol in e en ions be ween 1997 and 2016. The e was e idence o
good p og ess wi h he con ol o se e al species, no ably Opun ia s ic a (Aus alian pes pea ), Sesbania punicea
( ed sesbania), Lan ana cama a (lan ana) and se e al in asi e aqua ic plan species, mainly because o e ec i e
biological con ol. On he o he hand, o e one hi d (38%) o he unding was spen on species ha ha e
subsequen ly been ecognised as being o lowe p io i y, mos o which we e alien annuals. The alloca ion o
unds o non-p io i y species was some imes d i en by he need o mee addi ional objec i es (such as
employmen c ea ion), o by pe cep ions abou ela i e impac in he absence o documen ed e idence.
Managemen goals we e also limi ed o inpu s ( unds disbu sed, employmen c ea ed) o ou pu s (a ea ea ed)
a he han ecological ou comes, and p og ess was consequen ly no adequa ely moni o ed. The s udy
ecommended ha unds should be e-di ec ed o hose species ha clea ly pose g ea e h ea s, and o which
o he solu ions (such as biological con ol) a e no an op ion.
Con ol o in asi e Ch omolaena odo a a ( i i d weed) in he Hluhluwe-iM olozi Pa k, KwaZulu-Na al P o ince (Dew
e al., 2017; Te Bees e al., 2017). This s udy ook place in he 90000 ha Hluhluwe-iM olozi Pa k (HiP) in KwaZulu-
Na al, Sou h A ica. In es a ions o Ch omolaena odo a a we e i s no iced in 1978, and inc eased o co e almos
hal o he HiP (40000 ha) in 2003. A e a subs an ial in es men in con ol (ZAR 103 million in unding and 2000
pe son-yea s o e o ), in asions we e educed o accep ably low le els by 2011 (Figu e 6.4). A numbe o clea
ac o s con ibu ed o his success. They included ongoing di ec ion om a di e se p ojec s ee ing commi ee
(including manage s, esea che s, he p i a e sec o and communi y ep esen a i es), a apid esponse eam, a
ocus on a eas o low in es a ion, a e y l exible managemen app oach, egula moni o ing and gene ous
unding. In addi ion, Te Bees e al. (2017) epo ed ha “ he eam was only paid ollowing comple ion o a
con ac and a e a ho ough inspec ion o he quali y o he wo k by he P ojec Manage ”. These ea u es o he
HiP p ojec a e o en in ma ked con as o hose associa ed wi h mos o he s udies ou lined abo e, and in all
likelihood accoun o he di e ences in success. This wo k was, howe e , essen ially a species managemen
p og amme applied o a speci i c a ea, and he con ol o o he in asi e axa was no documen ed.
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THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
A ea (ha)
Ini ial ha clea ed
In aded Follow-up ha clea ed
60 000
50 000
40 000
30 000
20 000
10 000
0
1978
1980
1981
1982
1983
1987
1988
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
FIGURE 6.4 A ea in aded by Ch omolaena odo a a in Hluhluwe-iM olozi Pa k, and a eas clea ed and ollowed up be ween 2000
and 2013. Figu e ed awn om Te Bees e al. (2017).
Con ol o in asi e Ch omolaena odo a a ( i i d weed) in he Pa adise Valley and Roos on ein Na u e Rese es,
KwaZulu-Na al P o ince (Adam, Nge a a & Ramdhani 2017). This emo e sensing s udy ook place in he Pa adise
Valley and Roos on ein Na u e Rese es in KwaZulu-Na al, each app oxima ely 300 ha. I was es ima ed ha
con ol ope a ions educed he ex en o in asions om 154 o 3 ha be ween 2010 and 2015. No u he
in o ma ion was gi en, so he me hods employed in con ol, and he cos o he ope a ions is no known. Again
his wo k was essen ially a species managemen p og amme applied o a speci i c a ea, and he con ol o o he
in asi e axa was no documen ed.
6.4.3. Re u ns on in es men om con ol measu es
The economic cos s o plan in asions, and he economic bene i s o con ol, ha e also been he subjec o a
small numbe o s udies in Sou h A ica. The le el o unde s anding o impac s and hei economic cos s is low,
bu es ima es indica e ha he cos o some impac s (los wa e , g azing and biodi e si y) is cu en ly abou ZAR
6.5 billion pe annum, bu could become much highe as in asions g ow (De Lange & Van Wilgen, 2010). In he
case o biological con ol o in asi e plan s, all s udies ha e es ima ed e y high e u ns on in es men . By
compa ing he cos s o biological con ol esea ch and implemen a ion o he bene i s o es o ed ecosys em
se ices, o a oided ecosys em deg ada ion, and a oided ongoing con ol cos s, biological con ol was shown o
be ex emely bene i cial in economic e ms, wi h es ima ed bene i :cos a ios anging om 8:1 up o 3726:1 (Van
Wilgen & De Lange, 2011).
In o de o es ima e a e u n on in es men om pas mechanical and chemical alien plan con ol measu es a
a na ional scale, i would be necessa y o know bo h he his o ic cos o con ol, and he alue o impac s a oided
due o con ol. De Lange & Van Wilgen (2010) p o ided a c ude es ima e o he a ea ha emained ee o
in asions due o all his o ic con ol e o s in Sou h A ica, bu because he e we e la ge assump ions in making
his es ima e, he le el o ce ain y ega ding he es ima e is e y low. The es ima ed alue o po en ial ecosys em
se ices (wa e , g azing and biodi e si y) amoun ed o ZAR 152 billion annually (2008 ZAR alues, De Lange &

115
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THE EFFECTIVENESS OF CONTROL MEASURES
Van Wilgen, 2010). Al hough an es ima ed ZAR 6.5 billion was los e e y yea due o in ading alien plan s, his
would ha e been an es ima ed addi ional ZAR 41.7 billion pe yea had no con ol been ca ied ou (as in asions
would ha e been a mo e widesp ead). This indica es a sa ing o ZAR 35.2 billion e e y yea due o he e ec s
o his o ic con ol e o s, bu li le con i dence can be placed in his es ima e due o la ge and un es ed
assump ions used in making he es ima e. I does howe e sugges ha , po en ially, e u ns on in es men in o
in asi e species con ol p ojec s could be e y la ge.
A a i ne scale, some s udies ha e es ima ed e u ns on in es men om ca chmen -scale alien plan con ol
p ojec s. Hosking & Du P eez (2004) conduc ed cos -bene i analyses a six si es (Tsi sikamma, Kouga, Po
Elizabe h D i sands, Albany, Ka Ri e and Po Ri e ), and concluded ha “ca chmen managemen on all he
si es ca ied ou by he Wo king o Wa e P og amme is ine i cien ”, wi h bene i :cos a ios anging be ween
0.03 and 0.75, which indica es a nega i e e u n on in es men ( hough he bene i s o job c ea ion we e no
included). Van Wilgen e al. (1997) modelled he sp ead and e ec s o alien plan s on s eam l ow in he 8000 ha
Be g Ri e ca chmen (Wes e n Cape), and concluded ha such managemen would be “e ec i e and e i cien ”.
They es ima ed ha wa e could be deli e ed a a cos o 57 and 59 c/kl espec i ely, wi h and wi hou he
managemen o alien plan s, indica ing ha such managemen would be cos -e ec i e. The es ima e was based
on p ojec ed clea ing cos s o a ound ZAR 180000 pe yea o ini ial clea ing o e en yea s, and abou ZAR
25000 pe yea o main enance he ea e (1997 alues). Fill e al. (2017) subsequen ly e iewed he ac ual cos s
and e ec i eness o con ol ope a ions o e he pas 20 yea s in he ca chmen o he Be g Ri e . Thei s udy
ound ha he cos o con ol had amoun ed o almos ZAR 50 million by 2015 (2015 alues, 7.2 imes g ea e
han he ne p esen alue o cos s es ima ed in 1997), and ha al hough he co e o alien plan s was g ea ly
educed, o e 1000 ha s ill suppo ed dense o medium in asions (> 25% co e ), and he a ea occupied by
sca e ed Pinus plan s had inc eased by o e 3000 ha o > 5700 ha. I appea s he e o e ha he p ojec ed
e i ciencies we e no ealised, bo h because he con ol cos s we e unde es ima ed, and because con ol
me hods we e no e ec i ely applied (Fill e al., 2017).
Finally, he e ha e been se e al ecen s udies on he po en ial e u ns on in es men om in asi e plan con ol
ope a ions (Vundla e al., 2016; Muda anhu, Blignau & Nkambule 2016; Mo okong e al., 2016; Nkambule e al.,
2017). These s udies we e conduc ed by ASSET Resea ch, an A ican-ini ia ed and led esea ch and de elopmen
pla o m (h p://www.asse esea ch.o g.za/). The s udies ook place in he no he n KwaZulu-Na al, Mpumalanga,
Wes e n Cape and Eas e n Cape P o inces, whe e he economic iabili y o a ange o managemen scena ios
was modelled in o he u u e. The scena ios included a ange o a es a which in asi e plan s could sp ead in he
u u e, as well as scena ios wi h and wi hou he inclusion o alue-added p oduc s de i ed om he p ocessing
o biomass om in asi e plan s, and wi h o wi hou co- unding om he p i a e sec o . The esul s ypically
sugges ed ha he inclusion o alue-added p oduc s, and o co- unding, deli e ed highe , and posi i e, e u ns
on in es men , and ha a “do no hing” scena io would deli e nega i e ne p esen alues. These s udies sugges
ha he ope a ions could be i nancially iable in u u e, i he unde lying assump ions behind he models a e
alid. These assump ions included:
1. Tha clea ing will con inue in o he u u e, and will be ca ied ou e ec i ely and p o essionally;
2. Tha co- i nancing will be a ailable;
3. Tha he e will be due compensa ion o he se ices ende ed and he alue-added p oduc s p oduced;
4. Tha he es ima es o in aded a ea (de i ed om mapping exe cises) a e accu a e; and,
5. Tha he esou ces equi ed o comple e he p ojec s ha e been accu a ely es ima ed.
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THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
I is unlikely, howe e , ha mos o e en all o he abo e assump ions hold. The e is a low le el o con i dence in
he mapping o plan in asions (see Box 5.1); he cos s o con ol e o equi ed a e ou inely unde -es ima ed
by 3–7 imes (see abo e); alien plan con ol wo k is o en cha ac e ised by low le els o e i ciency; and he
inclusion o alue-added p oduc s could lead o unin ended consequences (Box 6.3). The e is consequen ly a
low le el o con i dence in hese p edic ions.
6.4.4. Nega i e impac s o con ol
The use o con ol measu es a e no wi hou po en ial nega i e non- a ge impac s. These e ec s ha e no been
assessed in his epo , bu should be a key componen o u u e epo s (Chap e 8).
6.5. SYNTHESIS AND INDICATOR VALUES
6.5.1. O e all e ec i eness o con ol measu es
This assessmen o he e ec i eness o con ol measu es has highligh ed a numbe o poin s. I would clea ly
be bene i cial o gain con ol o in asi e species because o he subs an ial economic cos s ha would
accompany widesp ead, ampan in asions (Box 6.1). In ecen yea s, he o e iding sou ce o unding o
con ol measu es was om he Wo king o Wa e p og amme wi hin he Depa men o En i onmen al A ai s
(Box 6.2). This public wo ks p og amme has spen ZAR 12 billion (unadjus ed o in l a ion) on in asi e plan
con ol p ojec s be ween 1995 and 2012. Howe e , his amoun has only been enough o con ol eams o
each somewhe e be ween 2% and 5% o he es ima ed ex en o he mos impo an in asi e species, and
consequen ly in asions con inue o sp ead (Van Wilgen e al., 2012; Hende son & Wilson, 2017). None heless,
he ac ha he Wo king o Wa e (W W) p og amme exis s, and is well- unded, is ema kable, especially o a
de eloping coun y. The e a e signi i can oppo uni ies o imp o emen s o W W (Box 6.2), some o hese a e
summa ised in he poin s below.
This assessmen has highligh ed ha he biological con ol o in asi e plan s has been no ably success ul. The
Sou h A ican go e nmen , h ough he W W p og amme, has con inued o und biological con ol esea ch and
implemen a ion, wi h e y encou aging esul s. O he 60 in asi e plan species o axa a ge ed o biological
con ol hus a in Sou h A ica, 15 species a e now unde comple e con ol, wi h a u he 19 species unde a
subs an ial deg ee o con ol (Zacha iades e al., 2017). By combining biological and mechanical and chemical
con ol, i has been possible o e ec i ely educe he popula ions o some o he mos damaging in asi e
species, as appea s o ha e been he case o Hakea and Acacia species in he Wes e n Cape (Esle e al., 2010;
Mo an & Ho mann, 2012), and o Lan ana and Opun ia species in he K uge Na ional Pa k (Van Wilgen e al.,
2017). The economic bene i s o hese in e en ions ha e been subs an ial, wi h es ima ed cos o bene i a ios
indica ing ha , o e e y one ZAR in es ed in o biological con ol, economic losses due o in asi e alien plan
in asions o be ween ZAR 8 and o e ZAR 3000 ha e been a oided.
A ew e adica ion p ojec s ha e been success ul, and mo e a e likely o ollow in he nea u u e. The numbe
o species a ge ed o e adica ion is inc easing, wi h se e al o he assessmen s o e adica ion easibili y
unde way.
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Se e al s udies ha e also shown ha con ol in e en ions ha e succeeded in educing he ex en o in asions
in some a eas. An ea ly example o his was p o ided by Macdonald, Cla k & Taylo (1989), who demons a ed
ha a p ope ly planned and execu ed app oach was able o subs an ially educe popula ions o in asi e alien
ees and sh ubs in he Table Moun ain Na ional Pa k. Conce ed e o s o emo e in asi e pine ees (and o he
species) om ynbos ecosys ems ha e esul ed in ma ked declines in he densi y o hese species in he Be g
Ri e Ca chmen ( unded by W W; Fill e al. 2017), and on he Ve gelegen Es a e (p i a ely unded; (Van Rensbu g,
Richa dson & Van Wilgen 2017). McConnachie e al. (2016) we e simila ly able o demons a e ha he in aded
a ea in he Hawequas Moun ains would ha e been almos 50% highe i he e had been no con ol in e en ion.
In sa anna ecosys ems, ongoing con ol has educed he deg ee o in asion by a numbe o species (including
Opun ia s ic a, Aus alian pes pea , and Lan ana cama a, lan ana, in he K uge Na ional Pa k (Van Wilgen e al.,
2017) and Ch omolaena odo a a, i i d weed, in he Hluhluwe-iM olozi Pa k (Dew e al. 2017; Te Bees e al. 2017).
Thus, a a local scale, some con ol measu es ha e demons ably been e ec i e.
Howe e , despi e he expendi u e o a leas ZAR 12 billion (o e 20 yea s, unadjus ed o in l a ion), and he
localised successes ou lined abo e, plan in asions ha e none heless gene ally con inued o g ow, some
subs an ially (see Hende son & Wilson, 2017; and he discussion in Chap e 4).
One o bigges p oblems impac ing on he e ec i eness o alien plan con ol measu es in Sou h A ica is he
lack o adequa e goal-se ing and planning, accompanied by he moni o ing o inpu s a he han ou comes. A
lack o clea s a egic planning and goal-se ing a guably leads o oo many p ojec s ha a e ine ec i e, a he
han ha ing ewe bu mo e e ec i e p ojec s in ag eed p io i y a eas. Successi e e iews o he Wo king o
Wa e p og amme (in 1997, 2003, 2012 and 2014) ha e explici ly aised he conce n o a lack o s a egic planning
(see Van Wilgen & Wannenbu gh, 2016, o a e iew). Mos alien plan con ol p ojec s in Sou h A ica ha e been
gi en goals o he amoun s o be spen , he numbe o people o be employed, and he a eas o be ea ed.
Moni o ing o p og ess has a ocus on hese goals, and he e a e ypically no goals ha desc ibe desi ed ou comes
in e ms o educing plan in asions o manageable le els, wha hose manageable le els would be, and how
long i would ake o achie e hem. In he absence o moni o ing p og ammes ha a e ocussed on hese
ecological ou comes, i is no possible o objec i ely assess managemen e ec i eness. The absence o adequa e
planning and moni o ing could be a ibu ed o he equi emen o minimise he cos s pe pe son-day (and hus
maximise he numbe o people employed), which is a key a ge on which con inued unding depends. This
educes he p og amme’s abili y o adequa ely in es in planning and moni o ing, which would be ela i ely
expensi e and would inc ease he o e all cos s pe pe son-day.
The exis ence o dual goals (ecological es o a ion and he c ea ion o employmen ) is a double-edged swo d.
On he one hand, i is absolu ely essen ial o he e en ion o he poli ical suppo ha ensu es unding, bu on
he o he i es ic s he abili y o ocus unds whe e hey a e mos needed o ecosys em es o a ion pu poses.
The achie emen o employmen and spending a ge s a e ela i ely easy o unde s and, as is he a ge o ea
a pa icula a ea. The a ge o an a ea o ea is no use ul, howe e , as i p o ides no guidance on he pu pose
o ea men ( o example o p e en e osion o , o o es o e, i al ecological se ices), no does i equi e he
quali y o e ec i eness o he ea men o be eco ded. The o mula ion o meaning ul a ge s o ecosys em
es o a ion, and a o mal equi emen o mee hem, could alle ia e his p oblem, bu gi en he cu en se o
measu es i is all oo easy o manage s o mee hei a ge s by simply c ea ing employmen and wo king
anywhe e o any s anda d.
118
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
Se e al s udies ha e shown ha he ac ual cos s o alien plan con ol ope a ions (be hey publically o
p i a ely unded) a e much la ge han he es ima ed cos s. Ac ual cos s should be 100% o he es ima ed
cos s, bu in a ange o s udies hey we e ound o be 150–860% (McConnachie e al., 2012); 300–500%
(McConnachie e al., 2016); 360% (Van Rensbu g, Richa dson & Van Wilgen 2017); and 720% (Van Wilgen e al.,
1997; Fill e al., 2017, wi h he p ojec s ill ongoing). These i ndings poin o he complexi y o e ec i ely
managing in asi e plan s, and he e o needed o add ess he issue, as well as o ine i ciencies in he
implemen a ion o managemen .
E ec i e con ol o in asi e species would equi e adhe ence o bes p ac ice me hods whe e hese a e a ailable.
This has no always been he case, and has led o ine i ciencies. Fo example, Macdonald, Cla k & Taylo (1989)
no ed ha he p ac ice o linking alien plan clea ing p ojec s o he supply o i ewood led o subs an ial
ine i ciencies. Fill e al. (2017) ound ha alien plan clea ing ope a ions in he Be g Ri e ca chmen , Wes e n
Cape, ailed o make adequa e use o powe ools, did no make any use o p esc ibed bu ning, and an un-
coo dina ed, sepa a e p ojec s o con ol plan s in accessible and inaccessible a eas, esul ing in ine i ciencies.
The equen ailu e o in eg a e biological con ol wi h mechanical and chemical con ol in many cases was
ou lined by Zacha iades e al. (2017), wi h, in one case, millions o ands spen mechanically clea ing Ce eus
jamaca u, a cac us species ha is unde comple e biological con ol (Van Wilgen e al. 2012a). McConnachie e al.
(2016) also no ed ha con ol success in he Hawequas Moun ains would ha e p e en ed a la ge a ea om
being in aded i i had ocussed all o i s clea ing e o on sca e ed plan s in un ans o med land, a he han on
dense in asions and abandoned plan a ions. Some o hese issues could be add essed by aligning plans wi h
bes p ac ice, bu o he s would equi e imp o ed aining o wo ke s o highe le els o compe ency. Fo example,
bo h he use o powe ools and he se ing o p esc ibed bu ns can be isky, and a e cu en ly a oided due o
conce ns o he sa e y o inadequa ely- ained wo ke s and o he s.
The employmen model cu en ly used by public wo ks p og ams can lead o subs an ial ine i ciencies. The
p ac ice o issuing sho - e m con ac s o clea ing and ollow-up (ins i u ed as a de elopmen al oppo uni y
o disad an aged con ac o s) equi es cumbe some p ocedu es o app o e and implemen , and esul s in
delays o wo k schedules and la e paymen s o in ended bene i cia ies, subs an ially dilu ing he in ended social
bene i s (Ash on, 2012; Coe ze & Louw, 2012; Hough & P ozesky, 2012). I would a guably be be e o employ
ewe , be e - ained, be e -equipped pe sonnel on a mo e pe manen basis. The cu en model also does no
allow o capaci y o be buil wi hin he conse a ion au ho i ies who a e ul ima ely manda ed o manage
p o ec ed a eas, and a scena io in which his unding is phased ou , o channelled elsewhe e, would lea e he
conse a ion agencies wi hou embedded capaci y and expe ience o manage in asions. Howe e , o he
employmen models a e used. Fo example, Wo king on Fi e, ano he in he sui e o public wo ks p og ams,
equi es bene i cia ies ha mee i ness s anda ds, p o ides aining o ensu e adhe ence o wo k s anda ds, and
employs people on an annual con ac basis, whe e hey ecei e a egula , dependable wage.
O e all, he e is a gene al conce n among many s akeholde s ega ding he e i ciency o go e nmen -sponso ed
alien plan con ol p ojec s, bu his is di i cul o subs an ia e due o he sca ci y o documen ed e idence. The
i ndings o McConnachie e al. (2012), and K aaij e al. (2017) ha poin o ine i ciencies in he applica ion o
ea men s, including non- ea men o a eas, p o ides some e idence. Shackle on e al. (2016), in a su ey o
pe cep ions o manage s, landowne s, o i cials and academics, ound ha mos landowne s (>80%) ega ded
125
CHAPTER 6
I
THE EFFECTIVENESS OF CONTROL MEASURES
The inpu indica o alues o money spen a e gi en in Table 6.5 ac oss all ac i i ies (pa hways, species and
a eas). The o he indica o alues o con ol e ec i eness o a ea managemen a e gi en in Table 6.10.
TABLE 6.10 Indica o s o con ol e ec i eness o a eas
INDICATOR VALUE
BASIC ADVANCED
LEVEL OF
CONFIDENCE NOTES
15. Planning
co e age
(inpu )
15.1. A eas ha
ha e managemen
plans in place.
4% o a eas ha e
plans
15.2. A eas ha
ha e managemen
plans in place, wi h
assessmen o
quali y o
managemen plans
2% o plans a e
adequa e
42% a e pa ially
adequa e
56% a e
inadequa e
15.3. As o 15.2,
wi h p io i y
ankings
No da a
15.1.
Medium
15.2.
Medium
15.3. N/A
Based only on plans
submi ed in e ms o he
alien and in asi e species
egula ions, bu he
absence o adequa e
plans is a well-
documen ed
phenomenon.
18. A ea ea ed
(ou pu )
18.1. P opo ion o a ea ha
needs o be managed and is
being managed.
0.36%
18.2. As o 18.1, wi h
in e en ions assessed o
adequacy.
No da a
18.1. Low
18.2. N/A
18.1. is based on he a ea
o un ans o med land in
Sou h A ica (973643
km2), assuming ha
8% (Ve s eld, Le Mai e
& Chapman, 1998)
(i.e. 77900 km2) is
in aded and needs o be
managed. The a ea ha
has been ea ed (282
km2) includes all land
pa cels ha ha e been
wo ked on by public
wo ks alien plan con ol
eams o e 20 yea s.
21. E ec i eness
o a ea
ea men s
(ou come)
21.1. P opo ion
o a eas in con ol
e ec i eness
ca ego ies AND an
assessmen o any
nega i e impac s
o con ol
No known: 99.6%
Coun e -
p oduc i e: 0%
None/Ine ec i e:
0.1%
Pa ially e ec i e:
0.2%
E ec i e: 0.1%
Pe manen : 0%
An assessmen o
he nega i e
impac s o con ol
has no been
made.
21.2. Quan i a i e
measu e o con ol
on Rela i e
in asi e
abundance o
In asi e species
ichness AND a
o mal
en i onmen al and
social assessmen
o non- a ge
e ec s o he
in e en ions
No da a
21.3. Re u n on
in es men
exp essed as a
a io o he
amoun spen on
con ol o he
alue o a oided
cos o impac .
AND non- a ge
impac s as cos s
Bene i :cos a ios
be ween 0.03 and
0.75
Non- a ge
impac s no
assessed
21.1. Low
21.2. N/A
21.3. Low
Fo 21.1., i was assumed
ha 77900 km2 is
in aded and needs o be
managed, and ha
282km2 is known o be
being managed (see
abo e). P opo ion in
e ec i eness ca ego ies
based on 12 a ailable
s udies (sec ion 6.4.2)
whe e he ou comes o
managemen we e
documen ed (8% we e
e ec i e, 58% we e
pa ially e ec i e, and
34% we e ine ec i e).
Bene i :cos a ios a e om
a single s udy in ol ing six
p ojec s (Hosking & Du
P eez, 2004)

126
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
6.6.5. Es ima ion o high-le el indica o s o o e all
managemen e ec i eness
High-le el indica o s a e p o ided in Table 6.11 (see Table 6.12 o he calcula ion).
The high-le el indica o o he Ra e o in oduc ion o new un egula ed species
was es ima ed based on he a e age o he decade 2000–2009 (see Figu e 3.8).
The Numbe o species ha ha e majo impac s was he sum o species conside ed
by expe s o ha e ei he majo o se e e impac s (Table 4.7). Howe e , as
explained ea lie , he e ha e been almos no o mal assessmen s o species
impac s, and hus he indica o should no be used as a basis o es ima ing
ends in u u e. A o mal e-assessmen o all alien species using he EICAT and
SEICAT me hods e e y h ee yea s is equi ed.
Ob aining an accu a e es ima e o he A ea expe iencing majo impac s would be dependen on: (1) a o mal
assessmen o he impac o indi idual species, and (2) a eliable es ima e o he dis ibu ion o hose species.
Cu en ly, bo h componen s do no exis . The es ima e o 1.4% is simply illus a i e. I assumes ha he a ea
es ima ed o be densely co e ed by alien plan s will expe ience majo impac s, and is based on a mapping
exe cise ha is bo h c ude and 20 yea s ou o da e (Le Mai e, Ve s eld & Chapman 2000).
The indica o o o e all Le el o success in managing in asions (Table 6.11) is calcula ed as he mean o es ima es
o le el o success o pa hways, species and a eas. Each was ob ained by mul iplying he p opo ion ha a e
ea ed ( om indica o s 16.1, 17.1 and 18.1 o pa hways, species and a eas espec i ely) by he weigh ed
ou come indica o s (indica o s 19.1, 20.1 and 21.1) as desc ibed o high-le el indica o D in Appendix 1. See
Table 6.12 o he alues a each s ep o he calcula ion.
TABLE 6.11 High-le el indica o s o he s a us o biological in asions and hei managemen in Sou h A ica in 2017.
HIGH-LEVEL INDICATOR VALUE LEVEL OF CONFIDENCE NOTES
A. Ra e o in oduc ion
o new un egula ed species
7 species
pe yea
Low Based on he a e age o he decade
2000–2009 (see Figu e 3.8)
B. Numbe o species
wi h majo impac s
107 species No applicable Based en i ely on expe opinion, and
so does no ep esen an app op ia e
base-line. Fo u u e epo s, o mal
assessmen s o impac will need o
be conduc ed (see Table 4.7)
C. Pe cen o a ea expe iencing
majo impac s
1.4% Low Based on he only a ailable es ima e
o dense (“condensed”) co e o
in asi e alien plan s in Sou h A ica
(1.7 million ha, (Le Mai e, Ve s eld &
Chapman, 2000))
D. Le el o success in managing
in asions
5.5% Low A e age o pa hway success (15.8%),
species success (0.65%) and a ea
success (0.0005%)
The e u ns on
in es men om
selec ed biological
con ol p ojec s aimed a
in asi e alien plan s a e be ween
8:1 & 3726:1
THE
SITUATION
127
CHAPTER 6
I
THE EFFECTIVENESS OF CONTROL MEASURES
TABLE 6.12 Values used o calcula e he high-le el indica o D. Le el o success in managing in asions. The p opo ion managed
is based on he ou pu indica o s: 16. Pa hways ea ed, 17. Species ea ed and 18. A eas ea ed. The p opo ion wi h pa ially
e ec i e/e ec i e o pe manen managemen is based on he ou come indica o s: 19. E ec i eness o pa hway ea men s, 20.
E ec i eness o species ea men s and 21. E ec i eness o a ea ea men s. The managemen e ec i eness sco e is calcula ed by
de e mining he sum o he weigh ed p opo ion wi h pa ially e ec i e managemen (mul iplied by 0.2) and he weigh ed
p opo ion wi h e ec i e managemen (mul iplied by 1). The le el o success is he p oduc o he p opo ion managed and he
managemen e ec i eness sco e.
PROPORTION
MANAGED
PROPORTION WITH
PARTIALLY EFFECTIVE
MANAGEMENT
PROPORTION WITH
EFFECTIVE OR PERMANENT
MANAGEMENT
MANAGEMENT
EFFECTIVENESS
SCORE
LEVEL OF
SUCCESS
(PROPORTION)
Pa hways 0.773 0 0.205 0.205 0.158465
Species 0.243 0.049 0.017 0.027 0.0065124
A eas 0.004 0.002 0.001 0.001 0.00000504
BOX 6.1 THE POTENTIAL ECONOMIC BENEFITS OF EFFECTIVE CONTROL MEASURES
Es ima es o he mone a y alue o impac s gene a ed by
in asi e species in Sou h A ica indica e subs an ial
nega i e e ec s in economic e ms. Fo example, one s udy
es ima ed ha , a le els o in es a ion in 2010, in asi e
alien plan s caused economic losses amoun ing o o e
ZAR 6 500 million e e y yea , mos ly o losses o wa e
uno , bu also o loss o li es ock p oduc ion om
in aded angelands, and income om biodi e si y- ela ed
goods and se ices.
Th ee poin s should be no ed wi h ega d o hese es ima es:
• Because o he lack o accu a e da a, i was necessa y o make a numbe o assump ions when making
hese es ima es. The es ima es a e he e o e c ude, bu a e la ge enough o indica e ha he eal economic
impac s could be subs an ial.
• The es ima es only include wa e uno , p oduc ion o li es ock om angelands, and limi ed biodi e si y
goods and se ices. The e a e many o he impac s associa ed wi h in asi e species ha we e no included
because o a lack o da a. These es ima es a e he e o e conse a i e, and will almos ce ainly be g ea e .
• The impac s will g ow as in asi e species con inue o sp ead, and as addi ional species become in asi e.
Gi en he la ge and g owing impac s o in asi e species, a emp s o con ain o educe hese impac s would
be economically jus i i able i he con ol measu es we e e ec i e and e i cien . The bes a ailable e idence o
his comes om he i eld o biological con ol. By compa ing he cos s o biological con ol esea ch and
implemen a ion o he bene i s o es o ed ecosys em se ices, o a oided cos s, and a oided ongoing con ol
cos s, biological con ol has been shown o be ex emely bene i cial in economic e ms: es ima ed bene i :
cos a ios anged om 8:1 up o 3726:1. This essen ially means ha o e e y one and in es ed in o con ol,
losses o be ween ZAR 8–3700 we e p e en ed.
Key e e ences:
Le Mai e e al. (2011); Van Wilgen & De Lange (2011a).
128
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
BOX 6.2 THE WORKING FOR WATER PROGRAMME: ACHIEVEMENTS AND CHALLENGES
The Wo king o Wa e P og amme (W W) is Sou h
A ica’s la ges unde o in asi e species con ol
measu es. Es ablished wi hin he Depa men o
Wa e A ai s in 1995 wi h an ini ial annual budge
o ZAR 25 million, i s o iginal pu pose was o
implemen in asi e plan con ol ope a ions o
educe hei impac s on wa e esou ces, and o
c ea e much-needed employmen amongs he
u al poo .
I has subsequen ly been mo ed o he
Depa men o En i onmen al A ai s, whe e i
emains he la ges o a sui e o p og ammes in he
Depa men ’s Na u al Resou ce Managemen
P og ammes. Cu en ly, i has an annual budge o
ZAR 1.5 billion, and employs 39500 people in 358
clea ing p ojec s ac oss he coun y.
W W has achie ed a g ea deal. The ac ha a p og amme o his size exis s a all, especially in a de eloping
coun y, is a ema kable achie emen , and i bea s es imony o he ha d wo k o hose esponsible o i s
es ablishmen and g ow h. The p og amme has secu ed ZAR 10 billion (unadjus ed o in l a ion) o in asi e
species managemen o e he pas 20 yea s, and has p o ided conse a ion agencies, wa e and i iga ion
boa ds, municipali ies and p i a e landowne s wi h unding o he managemen o in asi e alien plan s, ha
hey would o he wise no ha e had.
Howe e , he p og amme aces signi i can challenges. Despi e he gene ous budge , i is pa en ly inadequa e
o achie e e ec i e con ol e e ywhe e, and i is o ced o make choices abou whe e, and on which species,
o spend money. The i al poli ical suppo ha is needed o sus ain his p og amme a ises om i s
demons a ed abili y o c ea e employmen , bu his can be a double-edged swo d as he employmen goal is
o en gi en highe p io i y han he goal o achie ing ecological es o a ion (and all o he bene i s ha go
wi h ecological es o a ion). The need o maximise employmen also educes he p og amme’s abili y o
in es adequa ely in planning and moni o ing, which would be expensi e and would inc ease he o e all
cos s pe pe son-day. Minimising he cos s pe pe son-day (and hus maximising he numbe o people
employed) is a key a ge on which con inued unding depends. Consequen ly, he p og amme’s
achie emen s a e a guably a less han hey could ha e been unde di e en ope a ing ules.
Key e e ence:
Van Wilgen & Wannenbu gh (2016).
129
CHAPTER 6
I
THE EFFECTIVENESS OF CONTROL MEASURES
BOX 6.3 THE POTENTIAL CONTRIBUTION OF BIOMASS UTILISATION TO THE EFFECTIVE
CONTROL OF INVASIVE SPECIES.
Pho og aphe : B. an Wilgen
Example o a p o o ype low-cos housing uni ha
u ilises chip-boa d manu ac u ed om in asi e alien
plan biomass.
Gi en ha he clea ing o in asi e species (especially
woody species) can gene a e a la ge amoun o po en ially
use ul biomass, i seems logical ha he oppo uni y
should be aken o make use o his biomass. Cu en ly,
Sou h A ica’s Na ional S a egy on Biological In asions
calls o clea ecommenda ions o be made on his
app oach based on “an assessmen o he easibili y,
iabili y and e ec i eness o p ojec s aimed a p oducing
ene gy [and o he p oduc s] om plan biomass”. Such an
assessmen has no ye been ca ied ou . Sou h A ica has
ne e heless al eady es ablished se e al ac o ies ha
manu ac u e u ni u e om alien plan wood, and is
se iously in es iga ing he po en ial o mass-p oduce
low-cos housing om alien plan biomass.
Despi e he appa en subs an ial po en ial o biomass u ilisa ion o con ibu e o in asi e plan con ol
e o s, i would be p uden o in es iga e his ho oughly be o e making any decision o implemen
u ilisa ion on a la ge scale. A numbe o poin s need o be explici ly conside ed:
• De eloping he in as uc u e o p ocess biomass could c ea e a la ge dependency on a esou ce ha is
a ge ed o educ ion o e y low le els. This would be p oblema ic as i could c ea e a subs an ial con l ic
in u u e.
• U ilisa ion does no necessa ily con ibu e o e ec i e con ol. U ilisa ion a ge s usable biomass, and does
no add ess smalle ees, egene a ion o e-sp ou ing, o seed banks. Si e dis u bance and anspo
could also ac ually exace ba e a he han educe he p oblem.
• U ilisa ion may only be economically easible in ce ain a eas, bu no in emo e o inaccessible si es, o in
cases whe e he e a e sca e ed popula ions ha should ecei e p io i y as a ge s o clea ing.
• U ilisa ion p ojec s can, and o en ha e, gene a ed unin ended consequences, including using
in as uc u e o p ocess non- a ge o indigenous species, o encou age sp eading o he a ge in asi e
species by people who wan o bene i om u ilisa ion p ojec s whe e he species does no ye occu .
Th ee s udies o he po en ial e ec i eness o u ilisa ion ha e been ca ied ou in Sou h A ica o da e. Mugido
e al. (2014) in es iga ed he easibili y o using ha es ed in asi e plan biomass in he Po Elizabe h a ea.
The s udy showed ha he p ojec p o ed o be “ i nancially iable”, bu only when he ene gy en ep eneu
ob ained biomass gene a ed by go e nmen - unded clea ing p ojec s a no cos , and hen only unde speci i c
condi ions. The po en ial use o Acacia cyclops om he De Hoop Na u e Rese e (Wes e n Cape) o gene a e
elec ici y was in es iga ed by Muda anhu, Blignau & Nkambule 2016. They concluded ha his would be
a ou able when compa ed o elec ici y gene a ion using diesel gene a o s. Finally, Vundla e al. (2016)
es ima ed he con ibu ion o alue-added p oduc s o he iabili y o woody plan con ol p ojec s in he
Kouga, K om and Ba iaans ca chmen s (Eas e n Cape). They concluded ha alue addi ion would inc ease he
e u ns on in es men om hese p ojec s. All o hese s udies a e p edic ions, based on assump ions,
including ha con ol ope a ions will be e ec i e and e i cien , and will be comple ed wi hin budge . Mo e
s udies a e needed o es ablish whe he his is he case.
Key e e ences:
Mugido e al. (2014); Vundla e al. (2016); Muda anhu, Blignau & Nkambule (2016) .
7
EFFECTIVENESS
OF REGULATIONS
Lead au ho s:
Tsungai Zengeya,
B ian an Wilgen,
John Wilson
Con ibu ing au ho s:
Tumelo Mo api,
Happiness Mnika hi,
Tendamudzimu Munyai,
Ka abo Malakalaka,
S iaan Ko zé,
Kha hu shelo Nelukalo,
Oupa Chauke,
Be na d Ndou
Chap e summa y
This chap e epo s on he cu en egula o y amewo k in Sou h A ica o
dealing wi h biological in asions, and speci i cally he e ec i eness o he Alien
and In asi e Species Regula ions (A&IS Regula ions) unde he Na ional
En i onmen al Managemen : Biodi e si y Ac (NEM:BA). E ec i eness is discussed
he e in e ms o managing pa hways o in oduc ion and dispe sal, indi idual
species and speci i c a eas, as well as on o he aspec s ha a e equi ed o be
epo ed on unde he A&IS Regula ions (e.g. s a e- unded esea ch).
Sou h A ica is one o he ew coun ies ha has comp ehensi e egula ions in
place o manage biological in asions, and many pa s o he egula ions a e
inno a i e. The egula ions deal wi h mos aspec s o biological in asions
(pa hways, species, and a eas) and mos mechanisms o implemen , upda e,
e iew, and appeal he egula ions a e clea , and as such we e a ed as
“subs an ial”. Howe e , al hough he e a e some sec ions o he legisla ion ha
a e ele an o he managemen o some speci i c pa hways (e.g. he in en ional
impo o alien species o he pe ade), he NEM:BA A&IS Regula ions do no
speci i cally egula e pa hways. In addi ion, he e a e se e al ac o s, such as he
lack o a na ional s a egy o manage biological in asions, as well as
o ganisa ional and human capaci y cons ain s, ha limi he implemen a ion
o he egula ions. The e idence base o lis ing species was no p esen ed in a
s anda d, anspa en manne p io o he p omulga ion o he egula ions,
al hough some species ha e subsequen ly been assessed. While hese
assessmen s a e consis en wi h he egula ions, hey do no mee in e na ional
bes p ac ice o isk analyses. A isk analysis amewo k has been de eloped
bu is s ill o be implemen ed.
Applica ions we e made o he impo o 6 unlis ed species and on he basis o
isk assessmen s o hese species, 21 impo pe mi s we e issued o i e
species. A o al o 647 pe mi s we e issued o es ic ed ac i i ies in ol ing 50
lis ed alien axa, including pe mi s o mul iple species ha a e lis ed in a ious
ca ego ies. Pe mi s we e o es ic ed ac i i ies ela ed o he ade (44%),
con eyance (26%), possession (21%), and impo (8%) o alien species, as well
as o esea ch (2%) on hese species. Fo lis ed in asi e alien plan s, no ices
ha e been se ed o he owne s o 85 p ope ies ac oss Sou h A ica (59 o
p i a e landowne s and 26 o plan ade s), wi h an o e all compliance o 95%.
Fo lis ed in asi e alien animals, no ices ha e been se ed o he owne s o 119
p ope ies (78 o pe shops, 19 o game a ms, 12 o p i a e holdings and 10 o
sanc ua ies o zoological ga dens) wi h an o e all compliance o 82%).

CHAPTER 7
I
EFFECTIVENESS OF REGULATIONS
CHAPTER 7
I
EFFECTIVENESS OF REGULATIONS
Species managemen p og ammes (as ca e ed o in he A&IS Regula ions) ha e only been
de eloped o Pa henium hys e opho us (pa henium) and Campuloclinium mac ocephalum
(pompom weed), as well as o he gene a Acacia (Aus alian wa les) and P osopis (mesqui e)
and he amily Cac aceae. None ha e ye been o mally implemen ed, so hei po en ial
e ec i eness canno ye be assessed.
Landowne s a e equi ed o no i y go e nmen o he lis ed in asi e species on hei land,
bu only 59 no i i ca ions we e ecei ed, cons i u ing less han 0.001% o he o al numbe o
land pa cels in he coun y.
Al hough equi ed, i is no possible o assess whe he , o o wha deg ee, he selle s o
immo able p ope y ha e no i i ed he pu chase o ha p ope y o he p esence o lis ed
in asi e species on ha p ope y, as he e is no legal equi emen o any pe son o he han
he pu chase o be no i i ed.
Only 29 a ea managemen plans ( e med “In asi e Species Moni o ing, Con ol and
E adica ion Plans” in he egula ions), co e ing abou 4% o he land-su ace o he coun y,
we e submi ed o he Depa men o En i onmen al A ai s (DEA) and he Sou h A ican
Na ional Biodi e si y Ins i u e (SANBI). Only one o hese plans was o adequa e quali y when
assessed agains he guidelines o he p epa a ion o such plans. The e o e, a lack o adequa e
planning emains an obs acle o he con ol o biological in asions in speci i c a eas.
O ganisa ions ha conduc s a e- unded esea ch on in asi e species mus lodge esea ch
p oposals and i ndings wi h SANBI. As o Ma ch 2017, no such p oposals o i ndings had
been lodged wi h SANBI, despi e a subs an ial amoun o esea ch being unded by he s a e.
A pe son who ails o comply wi h he p o isions o he A&IS Regula ions would be liable, on
con ic ion, o a i ne o imp isonmen , o bo h. To da e, no cases ha e been b ough o ial.
The egula ions ha e been in place o less han h ee yea s, and i is p obably p ema u e o
expec ha hei e ec i eness could be assessed a his ea ly s age. Howe e , a numbe o
impo an poin s eme ge, including: high le els o non-compliance wi h some egula ions; a
sho age o capaci y wi hin he DEA o ensu e compliance (al hough he magni ude o he
sho age has no been assessed); he appa en absence o a s a egic app oach o implemen
he egula ions in a capaci y-cons ained en i onmen ; and con es a ion o he desi abili y o
egula ions o pa icula species. Finally, whe e he e has been ac i i y and da a a e a ailable
o his epo , he da a only ocussed on ou pu s (e.g. numbe o pe mi s issued). Linking
hese da a o ou comes in e ms o he s a e o biological in asions in Sou h A ica will
equi e he de elopmen o ag eed me hodologies.
Limonium sinua um (s a ice) – So i a Tu ne
132
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
7.1 INTRODUCTION
In 2014 he go e nmen published he Alien and In asi e Species Regula ions (A&IS Regula ions) in e ms o he
Na ional En i onmen al Managemen : Biodi e si y Ac (NEM:BA, Ac 10 o 2004). These egula ions speci y he way in
which alien species a e o be managed. In addi ion, he egula ions p esc ibe he p ocess o be ollowed i a new alien
species is o be impo ed in o he coun y, and hey also lis species ha a e p ohibi ed om impo a ion. The in en
o he egula ions is o educe he isk o impo ing alien species ha could become in asi e and ha m ul, educe he
numbe o alien species becoming in asi e, limi he ex en o in asions, and educe he impac s caused by hese
in asions. This is o be achie ed, in pa icula , by assigning esponsibili ies o he con ol o lis ed in asi e species, and
whe e app op ia e o p esc ibe he condi ions unde which species ha a e bo h in asi e and bene i cial can be
owned, cul i a ed, anspo ed and aded, as well as assign he esponsibili y o owne s o p e en he sp ead o such
species. The egula ions also equi e ha esea ch p oposals, and esea ch i ndings should be submi ed o he Sou h
A ican Na ional Biodi e si y Ins i u e (SANBI). This includes any “ esea ch and biological con ol ela ing o any aspec
o he in asi eness o po en ial in asi eness o an alien species o a lis ed in asi e species o he p e en ion, e adica ion
o con ol o such in asi e o po en ially in asi e species” ha is wholly o pa ly unded by he s a e, o conduc ed in
e ms o a pe mi o ca y ou esea ch on a lis ed in asi e species. The egula ions u he equi e SANBI o epo ,
wi hin h ee yea s o he p omulga ion o he egula ions and e e y h ee yea s he ea e , on he e ec i eness o he
egula ions, based in e alia on no i i ca ions om land owne s, pe mi s issued, cancelled o e used, and managemen
plans submi ed (see Table 7.1 o de ails). This chap e conside s he e ec i eness o he NEM:BA A&IS Regula ions in
e ms o managing pa hways o in oduc ion and wi hin-coun y dispe sal, indi idual species and speci i c a eas, and
assessing alien species- ela ed esea ch. The e a e also se e al addi ional Ac s in Sou h A ica ha a e ele an o he
managemen o biological in asions. The mos impo an o hese (Box 7.1) a e unde he ju isdic ion o he
Depa men o Ag icul u e, Fo es y and Fishe ies (DAFF), and a e no co e ed in his epo .
TABLE 7.1. Aspec s o he Na ional En i onmen al Managemen : Biodi e si y Ac (NEM:BA) and he Alien and In asi e Species
(A&IS) Regula ions ele an o he managemen o species, a eas and esea ch.
CATEGORY ASPECT THAT REQUIRES REGULATION
RELEVANT SECTION OF
THE A&IS REGULATIONS
(AND OF NEM:BA AS SPECIFIED)
Regula ions ele an
o managing
indi idual in asi e
species
Pe mi s issued o he impo o new species ha
p e iously we e no in Sou h A ica
Sec ion 17
Pe mi s issued o axa in Ca ego y 2 and o he ca ego ies
ha a e al eady in he coun y; pe mi s e used o cancelled
Sec ion 9.1 (a); Sec ion 12(1);
Sec ion 21 (2) (b)
In asi e Species Managemen P og ammes Sec ion 9(1) I
Eme gency in e en ions and en o cemen ac ions
in ol ing lis ed in asi e species issued by he Minis e .
Sec ion 11 (2) (b) (i )
P osecu ion o o ende s Sec ion 35
Regula ions
ele an o
managing speci i c
a eas
No i i ca ions ecei ed om owne s o land ega ding he
lis ed in asi e species occu ing on hei land
Sec ion 11(2)(b)(i) o he egula ions, wi h
e e ence o Sec ion 73(2)(a) o he NEM:BA Ac
No i i ca ions and di ec i es issued o landowne s Sec ion 13(1)(a); Sec ion 31
Le el o compliance wi h p ope y ans e no i i ca ions Sec ion 29 (3)
In asi e Species Moni o ing, Con ol and E adica ion
Plans (i.e. a ea managemen plans) ecei ed om o gans
o s a e and managemen au ho i ies o p o ec ed a eas
Sec ion 8 (2) (b); Sec ion 9(1)(b)
In asi e species s a us epo s o p o ec ed a eas,
submi ed since 2004
Sec ion 77 (1) and (2) o NEM:BA
P osecu ion o o ende s Sec ion 35
Regula ions ele an
o esea ch on
biological in asions
Resea ch p oposals, and biological con ol p oposals,
submi ed
Sec ion 10 (1)
Resea ch epo s o publica ions submi ed Sec ion 10(4)
133
CHAPTER 7
I
EFFECTIVENESS OF REGULATIONS
BOX 7.1
ADDITIONAL LEGISLATION IN SOUTH AFRICA THAT IS RELEVANT TO THE
REGULATION AND MANAGEMENT OF BIOLOGICAL INVASIONS THOUGH
NOT SPECIFICALLY DEALT WITH IN THIS REPORT
The e a e se e al Ac s in Sou h A ica, in addi ion o he Na ional En i onmen al Managemen : Biodi e si y
Ac , ha a e ele an o he managemen o biological in asions. This box lis s examples o hese ac s, along
wi h he ele an epo ing equi emen s.
ACT ADMINISTERED BY REPORTING REQUIREMENTS
Ag icul u al Pes s Ac ,
1983 (Ac No. 36 o 1983)
Depa men o
Ag icul u e, Fo es y and
Fishe ies
• Compulso y no i i ca ions o ce ain pes s
om land use s
• Con ol measu es p esc ibed o di e en
axa, o in espec o di e en a eas, di e en
ci cums ances, o in o he espec s as he
Minis e may hink i
• Pe mi s ha ha e been issued o con olled
goods showing he eason o he pe mi
• O enses and success ul p osecu ions
Animal Diseases Ac ,
1984 (Ac No. 35 o 1984)
Depa men o
Ag icul u e, Fo es y and
Fishe ies
• Pe mi s o impo ed con olled animals o
o he i ems
• Con ol measu es o con olled animals o
o he i ems
• Repo s o con olled animal disease
• O enses and success ul p osecu ions
Animal Heal h Ac ,
2002 (Ac No. 7 o 2002)
Depa men o
Ag icul u e, Fo es y and
Fishe ies
• Repo s o con olled animal disease
• Pe mi s and heal h ce i i ca es o animals,
pa asi es, con amina ed o in ec ious i ems
ha ha e been impo ed in o he coun y
• O enses and success ul p osecu ions
Na ional En i onmen al
Managemen : P o ec ed
A eas Ac (Ac 57 o 2003)
The Depa men o
En i onmen al A ai s
• Regis e o alien species in p o ec ed a eas
• Pe o mance moni o ing indica o s
• O enses and success ul p osecu ions
Conse a ion o
Ag icul u al Resou ces
Ac (Ac 43 o 1983)
Depa men o
Ag icul u e, Fo es y and
Fishe ies
• Decla ed weed and in ade lis
• Weed con ol schemes and p og ess epo s
• Weeds on any seed, g ain, hay o o he
ag icul u al p oduc
• Weeds on any animal which is d i en on a
public oad, con eyed in a ehicle o o e ed
o sale a a li es ock auc ion
• O de s issued o weed des uc ion, emo al
o e u n o he abo e-men ioned weeds.
• Con ol plans o in ade s and weeds
• Di ec i es o complying wi h con ol
measu es
134
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
7.2. THE STATE OF THE CURRENT REGULATORY FRAMEWORK
The s a us o he cu en egula o y amewo k was assessed using he indica o Quali y o egula o y amewo k
(see Appendix 1 o mo e de ails). The indica o is an inpu indica o ha helps o add ess h ee ques ions: 1)
wha egula o y amewo k is in place o manage biological in asions; 2) wha is i s le el o comple eness (does
i co e all aspec s o pa hways, species, and a eas); and 3) wha mechanisms a e in place o enable i s
implemen a ion, upda e, e iew, and appeal? A a basic le el he indica o is mean o p o ide a coun y-le el
assessmen o he deg ee o which au ho i ies a e able o egula e he u ilisa ion, mo emen , and ade o alien
species and ci izens a e able o ake s eps o con ol p oblema ic in asi e species. A a mo e ad anced le el, he
indica o can be used o assess he quali y o he egula o y amewo k a lowe adminis a i e en i ies (e.g.
p o inces), and also o assess he le el o in e -agency co-ope a ion. The quali y o he egula ions is e alua ed
as ei he : none, pa ial, subs an ial o comple e based on hei comple eness and he p esence o enabling
mechanisms o implemen a ion, upda e, e iew, and appeal. In his epo he NEM:BA A&IS egula ions (2014)
we e assessed as “subs an ial” because hey deal wi h mos aspec s o biological in asions and mos mechanisms
o implemen a ion, upda e, e iew, and appeal a e clea . Howe e , pa hway speci i c ac ions a e pa ly add essed
and he e a e se e al ac o s such as he lack o a na ional s a egy o manage biological in asions, o ganisa ional
and human capaci y cons ain s ha may limi he implemen a ion o he egula ions (Table 7.2).
TABLE 7.2 A b eakdown o co e age o he Na ional En i onmen al Managemen : Biodi e si y Ac ’s Alien and In asi e Species
Regula ions (2014) ac oss all aspec s o biological in asions. This is wi h e e ence o indica o 13. Quali y o egula o y amewo k.
ASPECT OF REGULATIONS
ASPECT OF BIOLOGICAL INVASIONS
PATHWAYS
(incl. subca ego ies)
SPECIES
(incl. all axa)
AREAS
(incl. di e en spa ial
scales and owne ship)
Is he e a manda e o managemen
in e en ions? Pa ial Subs an ial Subs an ial
Is he e p o ision o en o cemen o
non-compliance? Pa ial Subs an ial Subs an ial
Is he e a equi emen o egula assessmen
o pe o mance, and e iew? Pa ial Subs an ial Subs an ial
7.2.1. Wha is equi ed o imp o e he e ec i eness o he egula ions?
Need o pa hway-speci i c managemen measu es. The NEM:BA A&IS Regula ions do no speci i cally egula e
pa hways bu se e al sec ions o aspec s o he egula ions a e ele an o he managemen o some pa hways.
Fo example, he egula ions equi e pe mi s o he impo o new species. Howe e , hese measu es a e ac ually
species-speci i c measu es and no pa hway managemen ac ions. The e is he e o e a need o he egula ions
o ha e pa hway speci i c-managemen measu es, o example he p oposed Ballas Wa e Ac ha is speci i cally
mean o p e en he ans e o alien and in asi e species in o Sou h A ican wa e s h ough he elease o
ballas wa e by ships.
Which alien species should be egula ed? Cu en ly, he NEM:BA A&IS egula ions lis 556 axa as in asi e. Howe e , no
all o hese species a e necessa ily ha m ul o he ex en ha would jus i y he expendi u e o ime and e o on hei
managemen , gi en ha capaci y o manage and o egula e is limi ed. Regula ions should he e o e a guably ocus
APPENDIX 1 – INDICATOR FACTSHEETS
237
Limi s o use ulness and accu acy
This indica o equi es de ailed mapping. I is hus mos likely o be used a smalle spa ial scales. I will ne e heless
be use ul o assessing he le els o in asion in pa icula ypes o a eas, o example p o ec ed a eas.
I equi es in o ma ion on indigenous abundances as well, and when dealing wi h co e age da a, he o al
co e age migh ei he be much g ea e han 100% (i.e. o e lapping canopies), o less han 100% (i.e. ba e ock).
The impac o di e en le els o ela i e abundance will also a y. So an unde s o y sh ub a 50% co e age migh
ha e much lowe impac s han a ine ha o e ops and smo he s ege a ion which is also a 50% co e age.
Upda ing he indica o
This indica o would be assessed a he scale o which managemen plans a e a ailable, and whe e goals a e se
o achie e educ ions in he ela i e abundance o alien species. Moni o ing and upda ing o he da abase on
which his indica o is based should be con inuous, as managemen is ongoing, likely as pa o annual planning
upda es. In Sou h A ica i is p oposed o upda e indica o s e e y h ee yea s.
Closely ela ed indica o s
DEPENDS UPON LINKS WITH REQUIRED FOR
5. Numbe and s a us o alien species
6. Ex en o alien species
7. Abundance o alien species
None 8. Impac o alien species
12. Impac o in asions
15. Planning co e age
19. E ec i eness o pa hway ea men s
20. E ec i eness o species ea men s
21. E ec i eness o a ea ea men s
B. Numbe o in asi e species ha ha e majo impac s
C. Ex en o a ea ha su e s majo impac s om in asions
D. Le el o success in managing in asions
Addi ional in o ma ion and commen s
The da a can be linked o o he GIS laye s o look a possible in e ac ions, e.g. wi h human oo p in .
Ra he han b oad axonomic g oups, i can be impo an o conside unc ional g oups, o unc ion i sel , e.g. wha
p opo ion o pho osyn hesis in a gi en egion is due o alien species (and how has his changed pos -in asion).

THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
238
12
IMPACT OF INVASIONS
Use and in e p e a ion
This indica o assesses he combined impac o all in asi e species wi hin a pa icula a ea on he deli e y o
selec ed ecosys em se ices, o on biodi e si y. I should ha e a ocus on hose ecosys em se ices ha a e
impo an in he con ex o he a ea conce ned ( o example on wa e esou ces in d y egions, li es ock
p oduc ion in angelands, o biodi e si y in p o ec ed a eas) and can be used o p io i ise a eas o managemen
in e en ions. A a mo e ad anced le el, he alue o impac s can be exp essed in mone a y e ms and so used
o calcula ions o cos s and bene i s o con ol.
Po en ial o agg ega ion
Impac s on ecosys em se ices ha a e made a i ne scales can be agg ega ed upwa ds a la ge scales.
Possible easons o upwa d o downwa d ends
Inc eases in impac (dec eases in ecosys em se ice deli e y) can be associa ed wi h he physiological o
compe i i e consequences o in asions. Fo example, displacemen o plan s ha a e able o conse e wa e
wi h species ha a e less e i cien wa e use s can educe s eam l ow and deple e g oundwa e esou ces; and
unpala able o hicke - o ming species can displace pala able g ass species in angelands, educing he li es ock
ca ying capaci y.
Upwa d ends can also be he esul o inc eases in he sp ead o alien species; shi s in which alien species a e
in asi e owa ds mo e damaging species; o due o he acc ual o impac o e ime, as e en i ex en o
abundance o in asions do no change o e ime, biophysical h esholds can be c ossed leading o ecosys em
le el impac s (Suding & Hobbs, 2009).
Implica ions o biodi e si y managemen o change in he indica o
The size and alue o impac s would be impo an ac o s o conside when alloca ing sca ce managemen
esou ces o add ess and hope ully educe, o slow he g ow h o , ha m ul impac s. Managemen esou ces
should be di ec ed o hose a eas whe e a ac i e e u ns on managemen in e en ions could be ealised
(po en ially, bu no necessa ily) including a eas whe e he impac s a e g ea es .
Uni s in which i is exp essed ( om basic o ad anced)
12.1
Fac o wi h i e le els o impac :
• No known
• Mino
• Mode a e
• Majo
• Massi e
12.2
The educ ion caused by he in asions exp essed quan i a i ely in he uni s in which he ecosys em se ice is
measu ed ( o example, wa e yield exp essed in m3 pe ha, and angeland ca ying capaci y in li es ock uni s
pe ha).
12.3 Ne p esen mone a y alues o he educ ion in he ele an ecosys em se ice o biodi e si y indica o s.
APPENDIX 1 – INDICATOR FACTSHEETS
239
Desc ip ion o sou ce da a
The use o his indica o equi es da a on he spa ial dis ibu ion and magni ude o ecosys em se ices, and on
he impac o in asions on ha se ice. While he magni ude o a wide ange o ecosys em se ices can be
assessed, good in o ma ion on he impac s o in asions on hose se ices a e sca ce, as ela i ely ew s udies
ha e been conduc ed.
Calcula ion p ocedu e
12.1
Ecosys em se ices should be mapped a app op ia e scales, and his is mo e easily achie ed o some
se ices ( o example wa e o imbe ex ac ion, o li es ock o i sh p oduc ion) han o o he s ( o example
aes he ic o cul u al alues). The impac o in asions on hese se ices should be modelled based on esea ch
esul s whe e hey a e a ailable, and ex apola ed.
• No known: he e has been no es ima e o whe he he e has been a educ ion in he ele an ecosys em
se ice o biodi e si y indica o s a ibu able o he in asions.
• Mino : he e has been a < 2% educ ion in he ele an ecosys em se ice o biodi e si y indica o s
a ibu able o in asions.
• Mode a e: 2–10% educ ion.
• Majo : 10–50% educ ion.
• Massi e: > 50% educ ion.
12.2 As o 12.1 bu whe e he da a a e o su i cien esolu ion and models o su i cien eliabili y ha a
quan i a i e pe cen age can be ob ained.
12.3 Con e sion o ecosys em se ices o mone a y alues would equi e u he esea ch in which he alue o
sus ainable yields (o wa e , li es ock, o ha es ed p oduc s) would ha e o be es ima ed o he scale conce ned.
Guide o applying con i dence le els
12.1
HIGH
Based on well-documen ed impac s o pa icula alien species combined wi h quan i a i e
in o ma ion on ela i e in asi e species abundance wi h a medium o high le el o con i dence
(see 11.2)
MEDIUM Based on well-documen ed impac s o pa icula alien species combined wi h quali a i e
in o ma ion on Rela i e in asi e abundance (see 11.1)
LOW Based on expe opinion
12.2
HIGH Based on le els o ecosys em se ices ha ha e been measu ed and quan i i ed ac oss he
egion; and on obus s udies ha quan i y he impac o in asions on hese se ices
MEDIUM Based on le els o ecosys em se ices ha ha e been measu ed o ep esen a i e pa s o he
egion, wi h well- es ed spa ial models used o ex apola e o he whole egion.
LOW Based on es ima es o ecosys em se ices de i ed om spa ial modelling, and/o on modelled
es ima es o he impac o alien species on hese se ices.
12.3
HIGH Based on di ec alua ion o measu ed and quan i i ed ecosys em goods and se ices in he
a ea conce ned.
MEDIUM Based on indi ec es ima ions o he ma ke alue o modelled le els o ecosys em se ices ( o
example, by compa ison o alues o simila se ices es ima ed elsewhe e).
LOW Based on ma ke alues o ecosys em se ices de i ed om expe opinion.
Mos e ec i e o ms o p esen a ion
12.1 Spa ially (on maps) o g aphically by means o ba g aphs showing ends o e ime o unde di e en
scena ios o in asion.
12.2 As o 12.1
12.3 Tables
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
240
A
B
Biodi e si y in ac ness %
Fynbos G assland Succulen
ka oo
Nama
ka oo
Sa anna and
hicke
0
10
20
30
40
50
60
70
80
90
100
Wi hou alien plan s
Wi h cu en le els
o in es a ion
Wi h u u e le els
o in es a ion
FIGURE A1.10 (Indica o 12.2) Es ima es o he Impac o in asions on wa e esou ces in Sou h A ica. In panel a) a e es ima es
o he educ ions in mean annual uno (MAR) due o in asi e alien plan s in he qua e na y ca chmen s o Sou h A ica. The
qua e na y ca chmen s whe e da a we e no a ailable o es ima e impac a e shown in g ey; in panel b) a e es ima es o he cu en
and po en ial impac s o in asi e alien plan s on su ace wa e uno in i e e es ial biomes in Sou h A ica (Le Mai e e al., 2016;
Van Wilgen e al., 2012).
Limi s o use ulness and accu acy
The ex en o which his indica o can be used is cons ained by limi ed spa ial in o ma ion on a wide ange o
ecosys em se ices (al hough in o ma ion on some o he mo e impo an se ices a e a ailable a a ange o
scales), accu a e dis ibu ion maps o biological in asions, and s udies ha ha e accu a ely quan i i ed impac s,
and on which models can be based. Howe e , as be e in o ma ion becomes a ailable, his could become an
in l uen ial indica o o in o ming policy-make s o he consequences o in asion.
Upda ing he indica o
This indica o should be upda ed a he same equency a which le els o in asion a e assessed.
Closely ela ed indica o s
DEPENDS UPON LINKS WITH REQUIRED FOR
5. Numbe and s a us o alien species
6. Ex en o alien species
7. Abundance o alien species
8. Impac o alien species
9. Alien species ichness
10. Rela i e alien species ichness
11. Rela i e in asi e abundance
13. Quali y o egula o y
amewo k
14. Money spen
15. Planning co e age
15. Planning co e age
20. E ec i eness o species ea men s
21. E ec i eness o a ea ea men s
B. Numbe o in asi e species ha ha e
majo impac s
C. Ex en o a ea ha su e s majo impac s
om in asions
D. Le el o success in managing in asions
Addi ional in o ma ion and commen s
The choice o wha o measu e in e ms o he impac o in asions will be in l uen ial and he impo ance o
di e en impac s will be con ex dependen . A “mino ” educ ion in biodi e si y in a biodi e si y ho spo migh
be much mo e impo an han a “massi e” educ ion elsewhe e; simila ly p o iding he cos o an in asion in
absolu e e ms migh hide majo and p o ound socie al inequi ies.
APPENDIX 1 – INDICATOR FACTSHEETS
241
13
QUALITY OF REGULATORY FRAMEWORK
Use and in e p e a ion
This is an inpu indica o ha helps add ess h ee key ques ions:
• Wha egula o y amewo k is in place o manage biological in asions?
• Wha is he le el o comple eness o his egula o y amewo k?; and,
• Wha mechanisms a e in place o enable implemen a ion, upda e, e iew, and appeal?
A a coun y le el, his indica o p o ides an assessmen o he deg ee o which au ho i ies a e able o egula e
he cul i a ion o use o alien species, hei anspo o ade, and o wha ex en ci izens a e equi ed o ake
s eps o con ol p oblema ic in asi e species. Volun a y ag eemen s should also be conside ed as ele an he e.
Po en ial o agg ega ion
This indica o would assess he quali y o he egula o y amewo k a a na ional le el, and he e would be no
need o agg ega ion. Can be assessed a lowe spa ial adminis a i e le els.
Possible easons o upwa d o downwa d ends
The indica o would change i new egula ions a e enac ed o ag eemen s eached.
Implica ions o biodi e si y managemen o change in he indica o
Inc eases o dec eases in he quali y o he egula o y amewo k would a ec he abili y o manage s o add ess
he nega i e e ec s o in asi e species.
Uni s in which i is exp essed ( om basic o ad anced)
13.1
Fac o wi h ou le els a a na ional le el:
• None [ he e a e no egula ions (o olun a y ag eemen s) on biological in asions]; and
• Pa ial ( egula ions a e enac ed and ha e clea mechanisms o implemen a ion and en o cemen ,
bu only co e some o he aspec s o he p oblem); and
• Subs an ial ( egula ions a e enac ed dealing wi h mos aspec s o he p oblem and/o esponsibili ies
a e mos ly clea ly assigned/mos mechanisms o implemen a ion, upda e, e iew, and appeal a e
clea ); and
• Comple e (comp ehensi e legisla ion go e ns biological in asions in a holis ic way, wi h esponsibili ies
clea ly assigned and clea mechanisms o implemen a ion, upda e, e iew, and appeal).
13.2 As o 13.1 bu o a ange o di e en adminis a i e en i ies, and inco po a ing an e alua ion o in e -agency
co-ope a ion
Desc ip ion o sou ce da a
Gaze ed legisla ion applicable o biological in asions; and published codes o conduc .
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
242
Calcula ion p ocedu e
13.1 Assessmen s by expe s on he quali y o legisla ion based on comple eness (co e s all aspec s o pa hways,
species and a eas); mechanisms o implemen a ion; upda e; and e iew; and appeal p ocesses
13.2 As o 13.1 a di e en adminis a i e le els and inco po a ing an e alua ion o in e -agency co-ope a ion
Guide o applying con i dence le els
13.1
HIGH Assessmen o egula ion quali y p o ided by an independen eam o expe s ha includes
bo h in asion scien is s and membe s o he legal p o ession
MEDIUM Assessmen o egula ion quali y p o ided by ei he an independen o semi-independen
eam. The eam includes in asion scien is s o membe s o he legal p o ession bu no bo h
LOW
Assessmen p o ided by a eam who ei he come om he ins i u ion esponsible o
de eloping o en o cing he egula ions and/o do no con ain assesso s quali i ed in in asion
science o law
13.2
HIGH As o 13.1
MEDIUM As o 13.1
LOW As o 13.1
Mos e ec i e o ms o p esen a ion
13.1 Table p o iding a b eakdown o co e age o he egula o y amewo k ac oss all aspec s o he p oblem, on
which he assignmen o one o he le els is based
13.2 As o 13.1
TABLE A1.3 A able p oposed o assessing he quali y o egula ions pe aining o biological in asions.
ASPECT OF REGULATIONS
ASPECT OF BIOLOGICAL INVASIONS
PATHWAYS
(incl. subca ego ies)
SPECIES
(incl. di e en
axonomic g oups)
AREAS
(incl. di e en spa ial
scales and owne ship)
Is he e a manda e o managemen
in e en ions?
De ailed /Pa ial/None
Is he e p o ision o en o cemen o
non-compliance?
Is he e a equi emen o egula
assessmen o pe o mance, and e iew?

APPENDIX 1 – INDICATOR FACTSHEETS
243
Limi s o use ulness and accu acy
Poli ically sensi i e indica o , migh be slow o change in esponse o p essu es.
Upda ing he indica o
I will be upda ed in esponse o he legisla i e p ocess (e.g. amendmen s o new egula ions).
Closely ela ed indica o s
DEPENDS UPON LINKS WITH REQUIRED FOR
1. In oduc ion pa hway p ominence
2. In oduc ion a es
3. Wi hin-coun y pa hway p ominence
4. Wi hin-coun y dispe sal a es
5. Numbe and s a us o alien species
6. Ex en o alien species
7. Abundance o alien species
9. Alien species ichness
8. Impac o alien species
12. Impac o in asions
14. Money spen
15. Planning co e age
16. Pa hways ea ed
17. Species ea ed
18. A ea ea ed
19. E ec i eness o pa hway ea men s
20. E ec i eness o species ea men s
21. E ec i eness o a ea ea men s
D. Le el o success in managing in asions
Addi ional in o ma ion and commen s
Can be a long p ocess o change o amend egula ions in ol ing public consul a ions and changes ha e o be
gaze ed o ake e ec .
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
244
14
MONEY SPENT
Use and in e p e a ion
The indica o ha measu es he mone a y inpu s in o he managemen o biological in asions. I p o ides a
basis on which o es ima e one o he main me ics o measu ing he ou come o managemen in e en ions,
namely e u n on in es men .
Po en ial o agg ega ion
This indica o can be agg ega ed ac oss any spa ial scale o all o he managemen in e en ions a ha scale.
Possible easons o upwa d o downwa d ends
Changes in poli ical o economic condi ions, esul ing in changes o he budge alloca ed o managing
biological in asions.
Implica ions o biodi e si y managemen o change in he indica o
Inc eased alloca ion can lead o an inc eased amoun o esou ces o unde ake in e en ions and dec eased
alloca ion can lead o a dec ease in he numbe o in e en ions implemen ed. Dec eases will also lead o he
need o p io i isa ion, and o conse a ion iage, so ha su i cien esou ces can be alloca ed o p io i y a eas
o achie e he goals o managemen .
Uni s in which i is exp essed ( om basic o ad anced)
14.1 Annual go e nmen expendi u e a a na ional scale
14.2 Annual go e nmen expendi u e sepa a ed in o expendi u e on he ele an componen s o pa hways,
species and a eas
14.3 As o 14.2 including expendi u e by p i a e indi iduals/o ganisa ions, and de ailed accoun s o he sou ces
o unding
Desc ip ion o sou ce da a
Reco ds o expendi u e om a ious go e nmen depa men s. Repo s o money spen by p i a e indi iduals/
o ganisa ions.
Calcula ion p ocedu e
14.1
Addi ion o expendi u e om di e en sou ces o ob ain a o al. When compa ed o e mul iple yea s, i would
be use ul o in l a e annual o als o ne p esen alues in he cu en yea . This would acili a e meaning ul
compa isons, especially in coun ies ha expe ience high le els o in l a ion.
14.2 As abo e, spli in o di e en uni s.
14.3 As abo e, spli in o di e en uni s.
APPENDIX 1 – INDICATOR FACTSHEETS
245
Guide o applying con i dence le els
14.1
HIGH Reco ds o expendi u e on biological in asions a e a ailable om all pa icipa ing agencies
MEDIUM Reco ds o expendi u e om all pa icipa ing agencies do no di e en ia e clea ly be ween
expendi u e on biological in asions and o he ac i i ies, leading o he need o assump ions
LOW Reco ds o expendi u e a e a ailable o some, bu no all pa icipa ing agencies
14.2
HIGH
Reco ds o expendi u e a e a ailable om all pa icipa ing agencies, wi h clea b eakdowns o
expendi u e in o p ojec s ha can be assigned easily o ele an componen s o pa hways,
species and a eas
MEDIUM
Reco ds o expendi u e a e a ailable om all pa icipa ing agencies, bu hey do no
di e en ia e clea ly be ween expendi u e on biological in asions and o he ac i i ies, and/o
hey do no di e en ia e be ween expendi u e on pa hways, species, and a eas, leading o he
need o assump ions
LOW Reco ds o expendi u e a e a ailable o some, bu no all pa icipa ing agencies, and/o i is
e y di i cul o asc ibe known expendi u e o di e en aspec s o biological in asions
14.3
HIGH As o 14.2, bu wi h he addi ional equi emen ha eco ds a e a ailable o money spen by
p i a e indi iduals/companies
MEDIUM As o 14.2, bu wi h he addi ional equi emen ha eco ds a e a ailable o money spen by
p i a e indi iduals/companies
LOW As o 14.2, bu wi h he addi ional equi emen ha eco ds a e a ailable o money spen by
p i a e indi iduals/companies
Mos e ec i e o ms o p esen a ion
14.1 G aphic p esen a ion o annual expendi u e o e ime
14.2 Tables o expendi u e pe componen ; wi h g aphical summa y o how his has changed o e ime
14.3 As o 14.2
Expendi u e (Millions o ZAR)
Financial Yea
1995/96
1996/97
1997/98
1998/99
1999/00
2000/01
2001/02
2002/03
2003/04
2004/05
2005/06
2006/07
2007/08
2008/09
2009/10
2010/11
2011/12
2012/13
2013/14
2014/15
2015/16
2016/17
R -
R 2 00
R 4 00
R 6 00
R 8 00
R 1 000
R 1 200
R 1 400
R 1 600
R 1 800
R 2 000
FIGURE A1.11 (Indica o 14.1)
Annual expendi u e by Sou h A ica’s
Wo king o Wa e P og amme, he main
p og amme o go e nmen con ol o
biological in asions (does no include
spending on ag icul u al pes s, o animal
and human pes s o diseases). Da a om
W W planning si e (h ps://si es.google.
com/si e/w wplanning/), downloaded July
2017. Values a e as epo ed pe yea , and
no adjus ed o in l a ion o gi e a ne
p esen alue.
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
246
Limi s o use ulness and accu acy
Go e nmen expendi u e da a will be ha d o colla e as expendi u e will be in mul iple depa men s some o
which will no iew he cos s as ele an o in asions o sepa a e hese om o he cos s (human heal h in
pa icula ). Con ibu ions om he p i a e sec o , and p i a e landowne s a e unlikely o be eadily a ailable, a e
di i cul o es ima e, bu could be subs an ial. The indica o is he e o e likely o be an unde es ima e o inpu s.
Upda ing he indica o
This indica o could be upda ed annually.
Closely ela ed indica o s
DEPENDS UPON LINKS WITH REQUIRED FOR
None ( hough ul ima ely
o cou se all aspec s o
pa hways, species, and
a eas could come in o
he calcula ion) e.g. 5.
Numbe and s a us o
alien species; 6. Ex en o
alien species and 7.
Abundance o alien
species
8. Impac o alien species
12. Impac o in asions
13. Quali y o egula o y amewo k
15. Planning co e age
16. Pa hways ea ed
17. Species ea ed
18. A eas ea ed
19. E ec i eness o pa hway ea men s
20. E ec i eness o species ea men s
21. E ec i eness o a eas ea men s
B. Numbe o in asi e species ha ha e majo impac s
D. Le el o success in managing in asions
Addi ional in o ma ion and commen s
None
APPENDIX 1 – INDICATOR FACTSHEETS
253
Closely ela ed indica o s
DEPENDS UPON LINKS WITH REQUIRED FOR
1. In oduc ion pa hway p ominence
2. In oduc ion a es
3. Wi hin-coun y pa hway p ominence
4. Wi hin-coun y dispe sal a es
5. Numbe and s a us o alien species
6. Ex en o alien species ( equi ed o
wi hin-coun y dispe sal a es)
13. Quali y o he egula o y amewo k
(needed o planning co e age)
15. Planning co e age
14. Money spen
17. Species ea ed
18. A eas ea ed
19. E ec i eness o pa hway ea men s
A. Ra e o in oduc ion o new un egula ed species
D. Le el o success in managing in asions
Addi ional in o ma ion and commen s
The le el o ea men equi ed should be p opo iona e o he a e o in oduc ion and hus should no be
consis en ac oss pa hways. Fo some pa hways i migh be di i cul o access da a. Fo example, some anspo
da a a e owned by companies and o gain access o he da a o da abases a ee is o en equi ed.
Some pa hways migh no need ea men (see indica o 15).

THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
254
17
SPECIES TREATED
Use and in e p e a ion
This ou pu indica o p o ides an indica ion o he deg ee o which alien species ha need o be managed a e
being managed.
Po en ial o agg ega ion
I can be agg ega ed ac oss axonomic g oups.
Possible easons o upwa d o downwa d ends
The p opo ion o known alien species ha a e being subjec ed o managemen could inc ease i a ailable unds
a e inc eased, bu could also inc ease i he unding emains unchanged, bu is sp ead ac oss mo e species.
Dec eases could signal ei he a dec ease in unding, o a decision o ocus a ailable unds on ewe species.
Changes could also be he esul o changes in he o al numbe o alien species.
Implica ions o biodi e si y managemen o change in he indica o
Managing a highe p opo ion o alien species could be in e p e ed as ad an ageous, bu i could also signal a
dilu ion o sca ce unds, leading o less e ec i e managemen pe species. A ad anced le els o his indica o , i
would he e o e be necessa y o examine whe he he le el o unding is adequa e o make a di e ence. Changes
hen will mo e closely co espond o changes in desi ed le els.
Uni s in which i is exp essed ( om basic o ad anced)
17.1 P opo ion o egula ed species ha a e being subjec ed o a managemen in e en ion
17.2
Fi e ca ego ies o he deg ee o which popula ions o an alien species iden i i ed as equi ing managemen
a e ac ually being managed
• No known;
• None;
• Pa ial;
• Subs an ial;
• Comple e.
17.3
As o 17.1 wi h each in e en ion (pe popula ion o ele an a ea) assessed as
• No known;
• Inadequa e;
• Pa ially adequa e;
• Adequa e.
Desc ip ion o sou ce da a
Species-speci i c managemen plans, including unds alloca ed pe species; es ima es o he amoun o unding
needed o achie e con ol, usually om esea ch p ojec s.
APPENDIX 1 – INDICATOR FACTSHEETS
255
Calcula ion p ocedu e
17.1 The numbe o alien species equi ing managemen is ob ained om indica o 15.
The indica o is he p opo ion o hese whe e managemen is being implemen ed.
17.2
As o 17.1 wi h an assessmen o he deg ee o which popula ions o an alien species a e being managed as:
• No known; and
• None (no popula ions a e managed); and
• Pa ial (< 75% o popula ions ha e some managemen ); and
• Subs an ial (> 75% o popula ions ha e some managemen ); and
• Comple e (100% o popula ions ha e some managemen ).
17.3
As o 17.1, wi h he quali y o he implemen a ion assessed agains s anda d c i e ia (e.g. all indi iduals/
s ages add essed, and bes p ac ice ollowed) as:
• No known ( he e is no moni o ing and epo ing in place); and
• Inadequa e (none o he c i e ia a e adequa ely ul i lled); and
• Pa ially adequa e (no all o he c i e ia a e adequa ely ul i lled); and
• Adequa e (all c i e ia ul i lled).
Guide o applying con i dence le els
17.1
HIGH Managemen plans eadily a ailable, up- o-da e, wi h p og ess epo s ha a e less han wo
yea s old. Lis o in asi e species known wi h high con i dence.
MEDIUM
No clea i all managemen plans ob ained, and/o he majo i y o managemen plans a e no
up- o-da e. P og ess epo a ailable bu somewha ou o da e (e.g. 2–5 yea s old).
Al e na i ely, he lis o in asi e species known wi h medium con i dence.
LOW
O e 50% o managemen plans a e ou o da e, wi h he las p og ess epo g ea e han 5
yea s ago, wi h no indica ion ha he plan has been w apped up. Al e na i ely, he lis o
in asi e species known wi h low con i dence.
17.2
HIGH As o 17.1, in addi ion wi h de ailed epo ing on popula ions ea ed and no ea ed (e.g. > 90%)
MEDIUM As o 17.1, in addi ion wi h some di ec da a indica ing co e age
LOW As o 17.1, in addi ion wi h he le el o co e age ex apola ed om some da a
17.3
HIGH As o 17.1, in addi ion he e has been a eliable (e.g. pee - e iewed) assessmen o he
adequacy o he ea men s o almos all (> 90%) species
MEDIUM As o 17.1, in addi ion he e has been a eliable (e.g. pee - e iewed) assessmen o he
adequacy o he ea men s o mos (50–90%) species
LOW As o 17.1, in addi ion he e has been a eliable (e.g. pee - e iewed) assessmen o he
adequacy o he ea men s o less han hal o high p io i y species
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
256
Mos e ec i e o ms o p esen a ion
17.1 P opo ion o di e en axonomic g oups
17.2 Ba cha
17.3 Ba cha
No example p esen ed he e.
Limi s o use ulness and accu acy
This ou pu indica o simply measu es he numbe o species ha a e being managed, unless he indica o is a
an ad anced le el ha includes an assessmen o he quali y o he con ol measu es. A his ad anced le el,
accu acy will depend on an unde s anding o wha ep esen s app op ia e s anda ds o con ol.
Upda ing he indica o
Can po en ially be linked o annual epo s, bu will likely only be done as pa o na ional epo ing cycles (e.g.
h ee yea s o Sou h A ica).
Closely ela ed indica o s
DEPENDS UPON LINKS WITH REQUIRED FOR
5. Numbe and s a us o alien species
6. Ex en o alien species
7. Abundance o alien species
9. Alien species ichness
13. Quali y o egula o y amewo k
15. Planning co e age
8. Impac o alien species
10. Rela i e alien species ichness
14. Money spen
16. Pa hways ea ed
18. A ea ea ed
20. E ec i eness o species ea men s
B. Numbe o in asi e species ha ha e
majo impac s
D. Le el o success in managing in asions
Addi ional in o ma ion and commen s
The species ha need o be ea ed migh include species ha a e no in oduced ye (i.e. p e-bo de ). In gene al
he ea men s should be wi h he goal o p e en ion, e adica ion, con ainmen o impac educ ion.
APPENDIX 1 – INDICATOR FACTSHEETS
257
18
AREA TREATED
Use and in e p e a ion
Ou pu indica o ha p o ides an indica ion o he a ea o e which alien species con ol ope a ions ook place.
Po en ial o agg ega ion
I can be agg ega ed om a eas wi h managemen plans o la ge spa ial scale.
Possible easons o upwa d o downwa d ends
The in aded a ea ha is subjec ed o managemen could inc ease i a ailable unds inc ease, bu i could also inc ease
i he unding emains unchanged, bu i managemen is shi ed om densely-in aded a eas o less densely in aded
a eas. Dec eases could signal ei he a dec ease in unding, o a decision o ocus a ailable unds on mo e densely
in aded a eas. The a ea ha can be ea ed also depends on he numbe o imes an a ea needs o be ea ed be o e
he managemen can mo e o new a eas. Some a eas equi e nume ous ollow-up ea men s ( o example o
emo e seedlings a e elling ma u e plan s), and his will slow he a e a which new a eas can be ea ed.
Implica ions o biodi e si y managemen o change in he indica o
A ea ea ed is an ou pu indica o ha can be used o gauge he p opo ion o he p oblem ha is being
add essed. This, in u n, p o ides an idea o whe he o no he in asion can be educed o an accep able le el
wi hin a easonable ime ame. Howe e , A ea ea ed is no an indica o o success, as he ou come o ea men
is no assessed.
Uni s in which i is exp essed ( om basic o ad anced)
18.1 The p opo ion o a eas ha need o be managed ha a e being managed
18.2
As o 18.1, wi h he quali y o he implemen a ion o each managemen plan assessed as:
• No known;
• Inadequa e;
• Pa ially adequa e; and
• Adequa e.
Desc ip ion o sou ce da a
Managemen plans om go e nmen ins i u ions, non-go e nmen al o ganisa ions and p i a e landowne s
Calcula ion p ocedu e
18.1 The a ea equi ing managemen is calcula ed (as pe indica o 15), and hen he p opo ion whe e
managemen plans a e being implemen ed is assessed.
18.2
As o 18.1, wi h he quali y o he implemen a ion o each managemen plan assessed agains s anda d
c i e ia (e.g. unding su i cien o each goal o e ec i e con ol; all a eas add essed; in oduc ion and
dispe sal pa hways conside ed; and bes p ac ice ollowed) as:
• No plan in place;
• Inadequa e (none o he c i e ia a e adequa ely ul i lled);
• Pa ially adequa e (no all o he c i e ia a e adequa ely ul i lled);
• Comple e (all c i e ia ul i lled).
THE STATUS OF BIOLOGICAL INVASIONS AND THEIR MANAGEMENT IN SOUTH AFRICA 2017
258
Guide o applying con i dence le els
18.1
HIGH Managemen plans eadily a ailable, up- o-da e, wi h p og ess epo s ha a e less han wo
yea s old. A eas equi ing managemen known wi h high con i dence.
MEDIUM
No clea i all managemen plans ob ained, and/o he majo i y o managemen plans a e no
up- o-da e. P og ess epo a ailable bu somewha ou o da e (e.g. 2–5 yea s old).
Al e na i ely, he a ea equi ing managemen is known wi h medium con i dence.
LOW
O e 50% o managemen plans a e ou o da e, wi h he las p og ess epo g ea e han 5
yea s ago, wi h no indica ion ha he plan has been w apped up. Al e na i ely, he a ea
equi ing managemen is known wi h low con i dence.
18.2
HIGH As o 18.1, and assessmen based on clea goals in managemen plans, and on egula and
e i i able moni o ing o p og ess
MEDIUM As o 18.1, and assessmen based on i egula moni o ing o p og ess
LOW As o 18.1, and assessmen based on expe local knowledge
Mos e ec i e o ms o p esen a ion
18.1 Maps o di e en a eas, displayed acco ding o app op ia e adminis a i e o biogeog aphical uni s.
18.2 Ba cha
No example p esen ed he e.
Limi s o use ulness and accu acy
I elies on he a ailabili y o epo s on moni o ing and e alua ion o con ol ope a ion.
Upda ing he indica o
Annually, in line wi h annual p ojec epo ing.
Closely ela ed indica o s
DEPENDS UPON LINKS WITH REQUIRED FOR
6. Ex en o alien species
7. Abundance o alien species
13. Quali y o he egula o y amewo k
15. Planning co e age
10. Rela i e alien species ichness
14. Money spen
16. Pa hways ea ed
17. Species ea ed
21. E ec i eness o a ea ea men s
C. Ex en o a ea ha su e s majo
impac s om in asions
D. Le el o success in managing in asions
Addi ional in o ma ion and commen s
I does no examine whe he hese ea men s we e e ec i e.

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