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Ecological risk assessment based on land cover change: A case of Zanzibar-Tanzania, 2003-2027

Abstract

Land use under improper land management is a major challenge in sub-Saharan Africa, and this has drastically affected ecological security. Addressing environmental impacts related to this major challenge requires faster and more efficient planning strategies that are based on measured information on land-use patterns. This study was employed to access the ecological risk index of Zanzibar using land cover change. We first employed Random Forest classifier to classify three Landsat images of Zanzibar for the year 2003, 2009 and 2018. And then the land change modeler was employed to simulate the land cover for Zanzibar City up to 2027 from land-use maps of 2009 and 2018 under business-as-usual and other two alternative scenarios (conservation and extreme scenario). Next, the ecological risk index of Zanzibar for each land cover was assessed based on the theories of landscape ecology and ecological risk model. The results show that the built-up areas and farmland of Zanzibar island have been increased constantly, while the natural grassland and forest cover were shrinking. The forest, agricultural and grassland have been highly fragmented into several small patches relative to the decrease in their patch areas. On the other hand, the ecological risk index of Zanzibar island has appeared to increase at a constant rate and if the current trend continues this index will increase by up to 8.9% in 2027. In comparing the three future scenarios the results show that the ERI for the conservation scenario will increase by only 4.6% which is at least 1.6% less compared to 6.2% of the business as usual, while the extreme scenario will provide a high increase of ERI of up to 8.9%. This study will help authorities to understand ecological processes and land use dynamics of various land cover classes, along with preventing unmanaged growth and haphazard development of informal housing and infrastructure.

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Ecological risk assessment based on land cover change: A case of Zanzibar-Tanzania, 2003-2027

Author: Omar, Hassan Mohammed
Year: 2020
Source: https://run.unl.pt/bitstream/10362/93717/1/TGEO0229.pdf
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ECOLOGICAL RISK ASSESSMENT BASED ON LAND COVER
CHANGE: A CASE OF ZANZIBAR-TANZANIA, 2003-2027
Hassan Mohammed Oma
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ECOLOGICAL RISK ASSESSMENT BASED ON
LAND COVER CHANGE:
A CASE OF ZANZIBAR-TANZANIA, 2003-2027
Disse a ion supe ised by
Ped o da Cos a B i o Cab al, PHD
P o esso , No a In o ma ion Managemen School
Uni e si y o No a Lisbon, Po ugal
Hanna Meye , PhD
P o esso , Ins i u e o Geoin o ma ics
Uni e si y o Muns e , Ge many
Ca los G anell Canu , PhD
P o esso , Ins i u e o New Imaging Technologies
Uni e si y o Jaume I Cas ellon, Spain
Feb ua y, 2020
ii
DECLARATION OF ORIGINALITY
I decla e ha he wo k desc ibed in his documen is my own and no om
someone else. All he assis ance I ha e ecei ed om o he people is duly
acknowledged and all he sou ces (published o no published) a e
e e enced.
This wo k has no been p e iously e alua ed o submi ed o NOVA
In o ma ion Managemen School o elsewhe e.
Lisbon, 17 h Feb ua y 2020
Hassan M. Oma
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ACKNOWLEDGEMENTS
Fi s ly, I would like o acknowledge ha , i is only by he G ace o Allah he Almigh y ha I ha e
made his a . The gi o li e, good heal h and sound mind ha has been g an ed has enable me
o accomplish his wo k.
I would like o hank all conso ium o E asmus Mundus Mas e 's p og am in Geospa ial
Technologies o hei inancial and ma e ial suppo du ing all pe iod o my s udy.
Special hanks a e due o my supe iso s P o . Ped o Cab al, P o . Ca los G anell Canu , and
P o . Hanna Meye , who p o ided imme se suppo o ensu e my wo k con o ms o s anda ds.
I would like o hank P o . D . Ma co Painho o con inuous hesis ollow up and encou agemen
and ensu ing ha , his wo k is comple e a he igh ime and in he igh s anda ds.
Finally, bu no leas , I wish o hank my daugh e , Haj a Hassan, my lo ely wi e Asha Sei , and
my whole amily o hei pa ience, inspi a ion, and unde s anding du ing he en i e pe iod o my
s udy. My iends and all ela i es o hei suppo , encou agemen and all hei con ibu ions o
make his s udy success.
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ECOLOGICAL RISK ASSESSMENT BASED ON
LAND COVER CHANGE:
A CASE OF ZANZIBAR-TANZANIA, 2003-2027
ABSTRACT
Land use unde imp ope land managemen is a majo challenge in sub-Saha an A ica, and his
has d as ically a ec ed ecological secu i y. Add essing en i onmen al impac s ela ed o his
majo challenge equi es as e and mo e e icien planning s a egies ha a e based on measu ed
in o ma ion on land-use pa e ns. This s udy was employed o access he ecological isk index o
Zanziba using land co e change. We i s employed Random Fo es classi ie o classi y h ee
Landsa images o Zanziba o he yea 2003, 2009 and 2018. And hen he land change modele
was employed o simula e he land co e o Zanziba Ci y up o 2027 om land-use maps o
2009 and 2018 unde business-as-usual and o he wo al e na i e scena ios (conse a ion and
ex eme scena io). Nex , he ecological isk index o Zanziba o each land co e was assessed
based on he heo ies o landscape ecology and ecological isk model. The esul s show ha he
buil -up a eas and a mland o Zanziba island ha e been inc eased cons an ly, while he na u al
g assland and o es co e we e sh inking. The o es , ag icul u al and g assland ha e been highly
agmen ed in o se e al small pa ches ela i e o he dec ease in hei pa ch a eas. On he o he
hand, he ecological isk index o Zanziba island has appea ed o inc ease a a cons an a e and
i he cu en end con inues his index will inc ease by up o 8.9% in 2027. In compa ing he
h ee u u e scena ios he esul s show ha he ERI o he conse a ion scena io will inc ease by
only 4.6% which is a leas 1.6% less compa ed o 6.2% o he business as usual, while he
ex eme scena io will p o ide a high inc ease o ERI o up o 8.9%. This s udy will help
au ho i ies o unde s and ecological p ocesses and land use dynamics o a ious land co e
classes, along wi h p e en ing unmanaged g ow h and haphaza d de elopmen o in o mal
housing and in as uc u e.

KEYWORDS
Ecological isk assessmen
Ecosys ems se ices
Land co e changes modelling
Landscape ecological s a is ics (LECOS)
Zanziba
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ACRONYMS
ANN A i icial Neu al Ne wo k
BAU Business as Usual
COLA Commission o Land
CONSV Conse a ion Scena io
DEM Digi al Ele a ion Model
ERI Ecological Risk Index
EXTRM Ex eme Scena io
FAO Food and Ag icul u e O ganiza ion
GDP G oss Domes ic P oduc
LCM Land Change Modele
LECOS Landscape ecological s a is ics
LUCC Land Use Land Co e Change
LULC Land Use Land Co e
MCE Mul i C i e ia E alua ion
MLP Mul i-laye Pe cep on
NEMC Na ional En i onmen Managemen Council
NBS Na ional Bu eau o S a is ics
RGZ Re olu ion Go e nmen o Zanziba
USGS Uni ed S a e Geological Su ey
UTM Uni e sal T ans e se Me ca o
WB Wo ld Bank
WWF Wo ld Wide Fund o Na u e
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INDEX OF THE TEXT
ACKNOWLEDGEMENTS ......................................................................................................... iii
ABSTRACT ................................................................................................................................. i
KEYWORDS ................................................................................................................................
ACRONYMS ............................................................................................................................... i
INDEX OF TABLES ................................................................................................................... ix
INDEX OF FIGURES ................................................................................................................... x
1. INTRODUCTION ................................................................................................................. 1
2. LITERATURE REVIEW ...................................................................................................... 4
2.1. Ecosys em se ices and hei bene i s ............................................................................ 4
2.2. The Cu en S a us o Ecosys em Se ices ..................................................................... 5
2.3. The Role o Remo e Sensing on Land use and Land Co e Change ............................. 6
2.4. Fu u e P o isions o Ecological Moni o ing h ough Land Change Modele ................ 8
3. STUDY AREA ...................................................................................................................... 8
4. DATA AND METHODS .................................................................................................... 11
4.1. Desc ip ion o he da a .................................................................................................. 11
4.1.1. Ex e nal a iables .................................................................................................. 12
4.2. Me hods ........................................................................................................................ 14
4.2.1. Image classi ica ion ............................................................................................... 14
4.2.2. Accu acy assessmen ............................................................................................. 15
4.3. Desc ip ions o he chosen scena ios ............................................................................ 16
4.3.1. Business as usual (2027BAU) ............................................................................... 16
4.3.2. Conse a ion scena io (2027CONSV) .................................................................. 16
4.3.3. Ex eme scena io (2027EXTM) ............................................................................ 16
4.4. P epa a ion o ex e nal (independen ) a iables ....................................................... 17
4.4.1. Fac o s ............................................................................................................... 17
4.4.2. Cons ain s ......................................................................................................... 19
4.5. Modelling Fu u e Scena ios wi h LCM ........................................................................ 20
4.5.1. Change Analysis .................................................................................................... 20
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4.5.2. T ansi ion po en ial ............................................................................................... 21
4.5.3. Change p edic ion ................................................................................................. 23
4.5.4. Model alida ion ................................................................................................... 24
4.6. Calcula ion o Ecological isk indices .......................................................................... 25
Ecological Risk index (ERI) ................................................................................................ 25
5. RESULTS ............................................................................................................................ 27
5.1. LULC changes 2003 - 2018 .............................................................................................. 27
5.2. Accu acy assessmen .................................................................................................... 28
5.3. LULC changes 2003 - 2018.......................................................................................... 30
5.4. Land Co e Change o u u e Scena ios ..................................................................... 31
5.4.1. Model alida ion esul s ........................................................................................ 31
5.4.2. Simula ed Maps o 2027 scena ios ...................................................................... 33
5.5. Ecological Risk Assessmen ......................................................................................... 35
5.5.1. Ecological Risk Indices o he yea 2003-2018 ................................................... 35
5.5.2. Ecological Risk Indices o 2027 scena ios .......................................................... 36
5.5.3. Dis ibu ion o ERI pe dis ic .............................................................................. 38
6. DISCUSSION ...................................................................................................................... 40
7. CONCLUSIONS AND RECOMMENDATIONS .............................................................. 42
Bibliog aphic Re e ences ............................................................................................................ 43
Annexes ................................................................................................................................... 49
Change analysis ....................................................................................................................... 49
P obabili y Ma ix.................................................................................................................... 49
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Al e na i ely, he coas al ecosys em like mang o e o es , seag ass beds, and co al ee s, p o ide
s ong suppo o hund eds o species o bo h ha d and so co als and ish as well as sea u les,
c us aceans, and ma ine mammals (A S aeh , 2018).
2.2. The Cu en S a us o Ecosys em Se ices
As (MA, 2005) sugges ed, ecosys em se ice bene i “is he bene i ha humans de i e om
ecosys ems”. Bu in e e se, human ac i i ies ha e been coined as he main agen o a majo
loses o des uc ion o global na u al ecosys ems (Chi, Zhang, Xie, & Wang, 2019). They cause
a majo p essu e in ecosys em species, by ei he imp ope use o na u al esou ces, o due o
inc easing in demands o ecosys em se ices in a pa icula socie y.
In ha sense, he ph ase like “ecosys em se ice loss” is mo e connec ed wi h he cos s ha mus
be paid o elie e he impac o ecosys em des uc ion on human p oduc ion and ea nings (Haden
e al., 2019). Acco ding o Millennium Ecosys em Assessmen epo o 2005, he e is a massi e
decline and h ea ening o ecosys em heal h which a e comp ises wi h he p o ision o ecosys em
se ices upon which indi iduals, communi ies and en i e cul u es depend (O e peck e al., 2013;
Rowland, 2019). This 2005 MA epo had p o ided an es ima ion o mo e han 60% o he
ecosys em se ices which ha e been assessed ac oss he globe a e al eady being deg aded o a e
used unsus ainably wi h he po en ial o become mo e deg aded in he i s hal o his cen u y.
The d i e s like he apid inc ease in human popula ion, mining ac i i ies, subsequen g ow h in
u baniza ion and in o mal se lemen s, oge he wi h o he h ea s, place eno mous s ess on he
ecosys em hea h and hus impac s hei u u e sus ainabili y (Engel, 2012). Zanziba and Tanzania
o example, ha e been epo ed o expe ience an ex ensi e decline in he s a e o i s en i onmen
h ough loss o na u al habi a s and biodi e si y o mo e han h ee decades (A. I. Ali, 2016).
Much o hese changes a e caused by he changes in LULC which a e in luenced by inc ease in
human popula ion, economic ac i i ies and poo managemen o u ban de elopmen s (NEMC,
2006).
Al e na i ely, he 2018 WWF’s li ing Plane epo , p o ide an es ima ion o up o 50% o he
global eshwa e and we land habi a s which ha e al eady been los in he pas 30 yea s since
1970 due o a ious human ac i i ies and clima ic a ia ion (Wo ld Wide Fund Fo Na u e
(WWF), 2018). These eshwa e and we land habi a s a e mo e essen ial in main aining
ecological p ocesses, as well as p o iding an app op ia e wa e lows wi hin an en i e wa e
ca chmen (Paul, 2013). Losing o des uc ing hese habi a s, would a ec he en i onmen al
lows including educing he olume, iming and e en he quali y o wa e lows which a e e y

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essen ial o he su i al o downs eam habi a s and species wi hin hose a eas (Paul, 2013).
In case o o es ecosys ems, which appea o be he mos undamen al sou ces o se ices and
global biodi e si y, hei abili y o main ain hei u u e sus ainabili y is po en ially h ea ened.
The ecen epo o Food and Ag icul u e O ganiza ion, p o ide an es ima ion o abou i e
million hec a e pe yea o global o es which ha e al eady been los be ween 2005 and 2015
(FAO, 2018). This es ima ion is e y wo se o he u u e de elopmen o biodi e si y and
ecosys em sus ainabili y, as well as h ea co esponding o he eedback on clima ic sys em and
ood secu i y (Ga zuglia, 2018). Wi hou p ope plan and managemen , he s a us o ecosys em
se ices will con inue o ace unp eceden ed s ess and p essu e, ha could esul in hei
deg ada ion and con e sion, he eby a ec ing hei sus ainabili y in bo h cu en and u u e
gene a ions.
2.3. The Role o Remo e Sensing on Land use and Land Co e Change
Remo e sensing is he science and o some ex en , he a o acqui ing in o ma ion abou he
Ea h’s su ace wi hou ac ually being in con ac wi h i (Paul, 2013). In combina ion wi h GIS,
Remo e Sensing (RS) p o ide a be e oppo uni y in s udying and analyzing he a ious o m o
he ea h's in o ma ion (Paul, 2013). I p o ides ooms o iew he ea h phenomenon om he
space, which enables he comp ehension o he cumula i e in luence o human ac i i ies on he
ea h's su ace's na u al s a e.
One o he majo applica ions o emo e sensing echniques is he classi ica ion o emo ely
sensed da a o mul i- empo al images. These echniques ha e been conside ed as an ul ima e oo
o a ious analysis and applica ions in he ield o emo e sensing (Mülle o á, Pe gl, & Pyšek,
2013). The undamen al objec i e o emo e sensing image classi ica ion is o di ide he emo ely
sensed image in o a numbe o classes (pixel g oup) in o de o e ec i ely examine and asses
wha changes ha e been occu ed in each o hose g oups (J. Xu, Feng, Zhao, Sun, & Zhu, 2019).
Howe e , he classi ica ion p ocess o emo ely sensed images is some ime conside ed o be he
mos complex ask in luenced by a ious ac o s such as a ailabili y o high-quali y images,
ancilla y da a, p ope classi ica ion p ocedu e, and analy ical abili y o he esea che (Gao & Xu,
2015) . In mos cases, i appea s o be much ha de o iden i y which is he bes classi ie o be
used in a pa icula s udy due o ei he he lack o p ope guidelines in selec ing he algo i hm o
e en he lack o a ailabili y o app op ia e classi ica ion algo i hms o a pa icula band (Gao &
Xu, 2015). In ha sense, many esea che s ha e made a g ea e o in p oposing he mos
e ec i e classi ica ion me hods o imp o e classi ica ion accu acy and as well as hei esul s.
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The mos popula emo e sensing classi ica ion me hods p oposed in di e en s udies a e
supe ised, and unsupe ised classi ica ion. In supe ised classi ica ion, he image pixels a e
classi ied by selec ing ep esen a i e samples o each land co e class (T aining Si es o A eas)
and hen he classi ica ion algo i hm applies hese samples o he en i e image (Bha acha ya,
Ca , & Pal, 2016). This p ocess is done in h ee majo s eps including selec ing aining a eas,
gene a e he signa u e ile and classi y he image. In ano he case, in unsupe ised classi ica ion
he images a e classi ied only by g ouping he pixels in o clus e s based on hei p ope ies i s ,
and hen he classi ica ion o each clus e wi h land co e classes a e done. In gene al, his
classi ica ion me hod is conside ed as he mos basic echnique, since he e is no need o aining
samples o classi y he image. I is a simple way o classi y he image wi h only wo majo s eps
including gene a ing clus e s and assigning classes (Bha acha ya e al., 2016).
All o hese classi ica ion me hods can be u he g ouped in ei he s a is ical me hods, decision
ees, a i icial neu al ne wo ks, and o he a i icial in elligence algo i hms (Xie, Li, Xiao, &
Peng, 2016). S a is ical me hods such as maximum likelihood classi ie and Bayesian classi ie
wo ks in an assump ion ha he membe s o each class in each band ollow a no mal dis ibu ion
in he ea u e space and calcula es he p obabili y ha a gi en pixel belongs o a speci ic class. In
his pa icula me hod, he classi ica ion accu acy dec eases as he dimension o ea u e dec eases
(Xie e al., 2016).
The decision ee me hods like andom o es classi ie make no assump ions conce ning he
dis ibu ion o he inpu ea u es and he e o e hey a e obus and e ec i e me hods in managing
nonlinea ela ionships among he class membe (J. Xu e al., 2019). Howe e , he e ec i eness
o he decision ee me hods is highly in luenced by he size o he ea u e space and hus a e no
app op ia e me hods o da a wi h a high dimension o ea u e space (J. Xu e al., 2019).
In he case o a i icial neu al ne wo ks (ANN) me hods p o e a powe ul pe o mance wi h a
highe dimensional ea u e space compa ed o s a is ical classi ica ion me hods because hey a e
dis ibu ion- ee (J. Xu e al., 2019). Howe e , he mos di icul ness o using ANN models is i s
demands o equi es a signi ican amoun o aining da a and a conside able numbe o i e a i e
aining p ocedu es o ensu e ha he models a e ained success ully. Al e na i ely, he
compu a ion o ANN algo i hms can be ex ao dina ily complex (J. Xu e al., 2019).
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2.4. Fu u e P o isions o Ecological Moni o ing h ough Land Change Modele
Spa ial and dynamic changes in LULC o he ea h’s su ace ha e a majo in luence on he
des uc ion and u u e p o ision o ecosys em sus ainabili y o bo h landscape s uc u e and
agmen a ion o g een space (Tian, Jim, Tao, & Shi, 2011). These dynamic changes in LULC
can esul in an inc ease in he le el o land abandonmen , s a a ion o e en mig a ion ou o he
a ec ed egion (Y. Wang e al., 2018). In ha kind o si ua ion, unde s anding he dynamics and
u u e land co e ends has o be conside ed as a majo componen in app o al s a egies o bo h
he planning and implemen a ion o app op ia e ools in conse ing he deg aded land.
A numbe o compu a ion algo i hms o moni o ing and p edic ing u u e land co e changes
ha e been widely inc eased in ecen yea s. The models like Ma ko chain (MC) (Al-sha i &
P adhan, 2014), a i icial neu al ne wo k (Pijanowski, B own, Shelli o, & Manik, 2001), cellula
au oma a (Cla ke & Gaydos, 1998), cellula Au oma a-Ma ko model (A sanjani, Kainz, &
Mousi and, 2011), bina y logis ic eg ession (A sanjani, Helbich, Kainz, & Boloo ani, 2012),
and simila i y weigh ed ins ance-based machine lea ning algo i hm (Sange mano, Eas man, &
Zhu, 2010) a e among he common used models o he u u e p edic ion and simula ion o
changes in land co e .
Land Change Modele (LCM) o example, was ound o be one among he e ec i e modeling
ool which inco po a es CA-Ma ko chain based on a neu al ne wo k o p edic u u e land-use
change (Eas man, 2006). This CA-Ma ko chain models inco po a ed in LCM a e ai ly simple
and much powe ul in modeling he complex p ocess and changes in land use o planning
pu poses (Eas man, 2006). I models he u u e land co e changes by making an assump ion ha ,
he p obabili y o sys em being in a ce ain ime can only be de e mined i i s p e ious s a e is
known wi h he assump ion ha a es o change obse ed du ing he calib a ion pe iod (T1 o
T2), will emain he same du ing he simula ion pe iod (T2 o T3).
LCM does also p o ides he ools ha can simula e he u u e land-use changes and pa e ns and
allowing es ing o al e na i e planning scena ios. Simula ing u u e land co e change unde
wha called scena ios, can p o ide a be e unde s anding o a ious planning al e na i es,
s imula ing policy discussions be ween en i onmen al and de elopmen goals, and he e o e
helping he esponsible au ho i ies in designing he new policies and p ocedu es ha c ea e
incen i es o ecological conse a ion (McKenzie, E., Rosen hal, A., Be nha d , J., Gi e z, E.,
Ko acs, K., Olwe o, N. and To , 2012).
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3. STUDY AREA
This s udy was conduc ed in Zanziba (Figu e 3.1), he small coas al island o abou 2,461 km²
in o al, loca ed a 39° 05’ E o 39° 55’ E and 4° 45’S o 6° 30’S Wes e n Indian Ocean, in which
ou ism and ag icul u al ac i i ies a e he majo economic sec o s con ibu ing abou 28% and
40% o i s GDP espec i ely (WB, 2019).
Zanziba is a pa o he Uni ed Republic o Tanzania, and consis s o wo main islands which a e
Unguja and Pemba and wi h almos 50 o he small isle s (Mye s, 2010; RGZ, 2008). These wo
islands a e loca ed 40 km o he mainland coas o Eas A ica in he Indian Ocean (Mye s,
2010). The wo main islands a e 50 km apa and a e sepa a ed by he 700 me e deep Pemba
channel. Howe e , he cu en s udy uses he e m Zanziba e e ing o he island o Unguja as
mos o he people li e in his island (Unguja), and because o Zanziba ci y loca ed in i (A
S aeh , 2018).
Acco ding o 2018 Na ional Bu eau o S a is ics (NBS) census epo , he o e all popula ion o
Zanziba island (include Pemba) is abou 1,348,776 people and i s annual g ow h inc ease in a
e y apid a e. In he ecen yea s, he popula ion g ow h a e o Zanziba has been epo ed o
g ow a a a e o 3.4 % annually (NBS, 2018). Na u al popula ion g ow h is conside ed as he
main agen o his high apid a e, bu o he ac o s including g owing o ou ism indus y and
economic in luence has also a ac ed a signi ican numbe o mig an s om Tanzania mainland
and o he pa s o Eas A ica, making his island o be one among he highly popula ed islands
in he wo ld.
Zanziba has a opical clima e wi h ou dis inc seasons. “Kaskazi” ( he ho season, which is
be ween Decembe and Feb ua y and associa ed wi h ei he li le o no ains), “Masika” which
is he long ainy season om Ma ch – May, “Kipupwe” ( he cold season, wi h s ong winds
be ween June and Sep embe ), and “Vuli” which is e y sho ainy season om Oc obe –
Decembe . The annual ain all o island is anging om 1600 mm o Unguja and 1900 mm o
Pemba espec i ely, and he ai empe a u es is anging be ween 29 and 32ºC on a e age.
Zanziba island was o iginally o es ed, bu p essu es like popula ion inc ease, human habi a ion
and clima e change and a iabili y ha e esul ed in widesp ead clea ing o he o es and
ege a ion co e (M. Kukkonen & Käyhkö, 2014).
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Figu e 3. 1: S udy A ea-Zanziba
The land co e pa e ns a ound Zanziba island a e gene ally dis ibu ed unde wo di e en soil
classes, namely he deep soil and he co al ag a eas. The deep soil a eas a e mainly a ibu ed by
pe manen cul i a ion and o es , while he la e co al ag a e cha ac e ized by cul i a ion and
consequen sc ublands (RGZ, 2008). Howe e , all o hese wo soil classes a e no s able in e ms
o i s land co e and bio ope cha ac e is ics. The hilly deep soil a eas a e epo ed o be mo e
ulne able o soil e osion, highly land use demands and simul aneously acing popula ion
p essu e, which all o hese in luences he apid and cons an changes in land co e pa e ns and
na u al esou ce (M. Kukkonen & Käyhkö, 2014; Mye s, 2010). Al e na i ely, shi ing
cul i a ion cha ac e ized in co al ag a eas c ea e a cons an elemen o changes, which unde he
p essu e o diminishing a ea due o comme cial and conse a ion land use may leads owa ds
de e io a ion o ecosys ems and aluable na u al esou ces (Mye s, 2010).

11
4. DATA AND METHODS
4.1. Desc ip ion o he da a
Da a om di e en sou ces we e used o achie e he objec i es o his s udy. A e y i s s ages,
he emo e sensed sa elli e images o Zanziba island (Table 4. 1) a di e en ime we e ob ained
om USGS websi e (www.ea hexplo e .usgs.go /), and hen compa ed based on hei di e en
empo al phenomenon. In ha sense, h ee mul ispec al Landsa images o he yea 2003, 2009
and 2018 wi h spa ial esolu ion o 30 m we e downloaded om USGS websi e (Table 4.1).
Ancilla y da a ep esen ing biophysical p ope ies ha we e conside ed o in luence land use
changes we e also applied in his analysis. These ancilla y da a we e ob ained by i s
downloading hei o iginal shape iles including Zanziba oad, p o ec ed o es , buildings and
illages as well as coas al egion om (www.zansdi.en i onmen . i ). By means o digi al
ele a ion model (DEM) which was ob ained om ( h p://openda a. cm d.o g ), we calcula e he
dis ance o each o hese a iables o c ea e he biophysical p ope ies o dis ance o he oad,
dis ance o he buildings, dis ance o he coas , dis ance o he o es and slope (Table 4.2).
P o ec ed a eas including p o ec ed o es , go e nmen al ag icul u al ield, as well as open and
es ic ed zones we e also used o ep esen he cons ain s o land co e changes in he s udy
egion. These p o ec ed a eas da a we e ob ained by eclassi ying he 2012 Zanziba LULC map
which was ob ained om Zanziba commission o land (COLA) o c ea e a Boolean map o 0
o p o ec ed a eas and 1 o all o he classes (Figu e 4.3).
12
Da ase
Desc ip ion
P ojec ion
Resolu ion
Sou ce
Landsa 7,
ETM+
Raw = 064, pa h =
166,
Da e: 14/01/2003
WGS 1984,
UTM Zone
37N
30 m
www.ea hexplo e .usgs.go /
Landsa 5
TM
Raw = 064, pa h =
166, Da e:
1/07/2009
WGS 1984,
UTM Zone
37N
30 m
www.ea hexplo e .usgs.go /
Landsa 7,
ETM+
Raw = 064, pa h =
166, Da e:
18/07/2018
WGS 1984,
UTM Zone
37N
30 m
www.ea hexplo e .usgs.go /
Digi al
Ele a ion Model
(DEM)
SRTM
Clipped om
Tanzania Dem
WGS 1984,
UTM Zone
37N
STRM
30 m
h p://openda a. cm d.o g
Table 4.1: Sa elli e Da a
4.1.1. Ex e nal a iables
In modeling LULC change o a speci ic a ea, he a iables in luencing o con olling he land
co e change on ha a ea should be p ope ly used as independen a iables, and he LU maps
should be used as dependen a iables. The inclusion o independen a iables in land change
modeling is e y essen ial since hese a iables ensu e he u u e land co e maps a e always
p edic ed wi h exis ing pa e ns and d i e s o changes in ha egion (Bulley, & Fü s , 2017).
In his s udy, he selec ion o independen a iables was based on e iews ela ed o simila
models, esea ches conduc ed in o he de eloping coun ies as well as he local ci cums ances o
Zanziba island. In ha sense, he a iables slope, dis ance o he oad, dis ance o he o es ,
dis ance o buildings, dis ance o he coas and p o ec ed a eas we e all selec ed as independen
a iables o simula e he u u e land co e change o Zanziba ci y.
The a iable “slope “was chosen o ep esen he biophysical condi ions o he s udy a ea.
Acco ding o (Liu, 2009; A sanjani e al., 2013), he la opog aphy has much in luence on land
co e changes han ugged opog aphy, and his heo y has al eady been used in many simila
models wi h posi i e esul s (Zhao e al., 2014).
“Dis ance o he oads” and “dis ance o he o es ” we e all connec ed o economic
ci cums ances. The chosen o dis ance o he o es in economic ac o s is connec ed wi h he ac
ha in Zanziba , he cus oms o con e ing o es ed land in o ei he buil -up a eas o a mland is
one o he majo eason o land-use dynamics, and his is highly caused by he economic si ua ion
o Zanziba popula ion (M. Kukkonen & Käyhkö, 2014). This a iable is also ela ed o local
13
spa ial policies o bidding any cons uc ions o de elopmen ac i i ies in p o ec ed o es (M.
Kukkonen & Käyhkö, 2014).
We ega d “dis ance o he coas ” and “dis ance o buildings” o be connec ed in he social ac o s.
In his case, he a iable “dis ance o he coas ” con i ms he global end owa ds highe
quan i ies o land-use changes in coas al egions (Ebada i, 2018). And o he second a iable
“dis ance o he buildings” exp ess he local social and planning condi ions o Zanziba , in which
he houses a e buil ela i ely close o each o he due o subdi isions o small landholdings. In
o he case, his phenomenon is also ela ed o spa ial in e ac ions, p o ided ha he land-use
changes a e highly a ac ed by simila changes in hei neighbo ing a eas (M. O. Kukkonen e
al., 2018; Toble sFi s Lawo Geog aphy, n.d.).
And in he case o he emaining a iable “p o ec ed a eas”, i has been used o ep esen he local
spa ial policies ha ha e ei he obs uc ed o indi ec ly s imula ed land-use dynamics (M. O.
Kukkonen e al., 2018).
Da ase
Desc ip ion
P ojec ion
Resolu ion
Sou ce
Dis - -
oad
Vec o con e ed
o as e ; Euclidian
dis ance o he oad
WGS 1984,
UTM Zone
37N
Re-sampled
o 30m
www.zansdi.en i onmen . i
(Commission o Land
adminis a ion Zanziba )
Dis - -
build
Vec o con e ed
o as e ; Euclidian
dis ance o he
building
WGS 1984,
UTM Zone
37N
Re-sampled
o 30m
www.zansdi.en i onmen . i
Dis - -
o es
Vec o con e ed
o as e ; Euclidian
dis ance o he
building
WGS 1984,
UTM Zone
37N
Re-sampled
o 30m
www.zansdi.en i onmen . i
Dis - -
coas
Vec o con e ed
o as e ; Euclidian
dis ance o he
beaches
WGS 1984,
UTM Zone
37N
Re-sampled
o 30m
www.zansdi.en i onmen . i
slope
Slope calcula ed
om digi al
ele a ion model
WGS 1984,
UTM Zone
37N
Re-sampled
o 30m
h p://openda a. cm d.o g
P o ec ed
a eas/
Cons ain
Vec o con e ed
o as e ;
Reclassi y o ha e
0 o p o ec ed
a eas and 1 o all
o he classes
WGS 1984,
UTM Zone
37N
Re-sampled
o 30m
www.zansdi.en i onmen . i
(Commission o Land
adminis a ion Zanziba
Table 4. 2: Ex e nal Va iables
14
4.2. Me hods
The o e all me hodology o his s udy was ca ied ou in o h ee majo s eps (Figu e 4.1). Fi s ,
he land use land co e classi ica ion was pe o med using andom o es classi ie o gene a e
h ee LULC maps o 2003, 2009 and 2018. Nex he land co e maps o he u u e scena ios
we e modeled using land change modele o he Te Se 18.3 so wa e. And inally, he ecological
isk indices o each map and each dis ic o Zanziba we e calcula ed by i s compu ing he
landscape me ics using LECOS plugin in QGIS 3.8, ollowed by applying he o mulas om
a ious li e a u es o ERI assessmen (Xue e al., 2019; F. Zhang e al., 2018; X. Zhang e al.,
2013).
4.2.1. Image classi ica ion
P e-p ocessing o all h ee sa elli e images (2003, 2009 and 2018), Zanziba adminis a i e
bounda y, oge he wi h all ancilla y da a Shape iles, was pe o med by using A cGIS 10.6. All
da ase s we e p ojec ed o WGS 1984, UTM Zone 37S coo dina e sys em, ollowed by band
combina ion, clipping o he s udy egion, and esampling o each one o hem o appea in he
same spa ial esolu ion o 30 m.
T aining Samples Shape ile o i e classes including buil -up, g assland, o es , we land and
a mland we e gene a ed by digi izing each o he sa elli e images. Wi h hese gene a ed i e land
Figu e 4. 1: Me hodological amewo k
21
4.5.2. T ansi ion po en ial
A e inishing he i s s ep o change analysis, he nex s ep was o es he explana o y powe
o each ex e nal a iable, as well as selec ing ansi ion sub-models ha a e ele an in he
p edic ion o he u u e scena ios.
The e o e, in his s age, i s , he C ame ’s powe o all ex e nal a iables we e es ed o iden i y
all a iables wi h a po en ial explana o y powe . These C ame ’s powe a e anging om 0 – 1,
in which he a iables wi h a leas 0.15 C ame ’s alue a e conside ed o be po en ial in land use
changes, whe eas hose ha ing alue om 0.4 onwa d a e much po en ial (Eas man, 2006).
The esul s o C ame ’s powe o each es ed a iable a e illus a ed in (Table 4.1) below.
Explana o y Va iable
O e all C ame ’s V alue
Dis ance o buildings
0.2852
Dis ance o oad
0.1836
Dis ance o he coas al a ea
0.1653
Dis ance o he o es
0.1354
Slope
0.0725
Res ic ed a eas
0.1932
Table 4. 3: C ame 's powe o ex e nal a iables
Due o he lowe C ame ’s alue, nega i e in luence on he modelling esul s, as well as less
li e a u es in o ma ion ega ding o Slope issues in Zanziba , his a iable was excluded in
analysis.
In he same sense, he a iable dis ance o he o es was also emo ed om he analysis due i s
lowe C ame ’s powe and i s nega i e in luence on he analysis accu acy.
The e o e, only h ee ex e nal ac o s including dis ance o he building, dis ance o he oad and
dis ance o he coas , and one cons ain map o each scena io (excep o ex eme scena io,
whe e cons ain s we e no employed) we e used in his analysis.
The nex s ep was o combine all selec ed a iables ( ac o s and cons ain ) oge he wi h
ansi ions sub-models be ween 2003 and 2009 and employ Mul i-Laye Pe cep on (MLP) o
gene a e ansi ion po en ial o 2018 land co e map p edic ion.
Mul i-Laye pe cep on (MLP) is a eed o wa d a i icial neu al ne wo k (ANN) composed wi h
one o mul iple laye s including inpu , ou pu and hidden laye s be ween inpu and ou pu laye .
The e m eed- o wa d me hod implying ha he da a lows in one di ec ion om inpu o ou pu .

22
The main algo i hm o his model is compu ing he linea ou pu om nonlinea inpu s acco ding
o he weigh s by using a nonlinea ac i a ion unc ion (Ga dne & Do ling, 1998).
MLP employs a supe ised lea ning echnique called backp opaga ion o aining. The back-
p opaga ion algo i hm composed o wo s eps which a e o wa d pass and backwa d pass. In he
o wa d pass, ac i a ion ansmi s om inpu o ou pu laye which means ha he signal low
mo es om he inpu laye h ough he hidden laye s o he ou pu laye . While in backwa d pass
e o s p opaga ed om ou pu o hidden laye (Ga dne & Do ling, 1998).
To model land-use ansi ions in LCM, ei he Logis ic Reg ession, SimWeigh o MLP neu al
ne wo k can be applied. Howe e , in his s udy, he MLP neu al ne wo k was applied because o
i s capabili y o unning mul iple ansi ions o up o 9 pe sub-model as well as explana o y
a iables a once (Eas man, 2006).
To achie e he be e accu acy on he esul s o Mul i-Laye Pe cep on only majo land co e
ansi ions oge he wi h only he d i e ’s a iables wi h highe C ame ’s powe should be
included in he ansi ion sub-model (Eas man, 2006).
Based on his p inciple, oge he wi h he in o ma ion om li e a u es ega ding on s udy egion,
only six majo ansi ions including g assland o buil -up, o es o buil -up, g assland o a mland,
o es o g assland, o es o a mland and a mland o g assland we e selec ed in his s udy.
Toge he wi h ou selec ed a iables, a Mul i-laye pe cep on was employed wi h an accu acy
o 68.4% o gene a e he ansi ion po en ials (Figu e 4.5) ha we e hen used by Ma ko chain
me hod o p edic he Land use map o he yea 2018.
The same p ocedu es we e also applied o model he 2027 maps.
23
Figu e 4. 4: T ansi ion Po en ial 2003 - 2009
4.5.3. Change p edic ion
The hi d s age in modeling u u e scena ios was o pe o m change p edic ion o a u u e
speci ied da e o he alloca ion o land co e changes. In his s age, he de aul p ocedu e in
LCM (Ma ko Chain analysis) was applied o de e mine he amoun o changes a a da e o 2018
based on his o ical land co e maps o 2003-2009.
He e, he algo i hm de e mines exac ly how much land would be expec ed o ansi ion om he
la e da e (2009) o he p edic ion da e (2018) based on a p ojec ion o he ansi ion po en ials
maps ha was gene a ed and hen c ea es a ansi ion p obabili ies ile (Eas man, 2006).
Wi h his ansi ion p obabili ies ile, wo p edic o s maps which a e so p edic ion map and a
ha d p edic ion map we e gene a ed. While a so p edic ion map is a con inuous mapping o
ulne abili y o change which p o ides an indica ion o he deg ee o which he a eas ha e he
igh condi ions o p ecipi a e change in 2018, a ha d p edic ion map is an ac ual p ojec ed map
o 2018, in which each pixel is assigned one land co e class; he class ha i is mos likely o
become (Eas man, 2006).
24
4.5.4. Model alida ion
To ensu e he p edic i e abili y and pe o mance o he model. Model alida ion and calib a ion
mus be pe o med be o e s a ing he p edic ion o LU changes o he speci ied da e. Pe o ming
alida ion o he model is a e y impo an s ep because he e iciency and usabili y o he model
a e always depending on he ou pu o he alida ion ( an Vlie e al., 2016).
Since se e al s udies ha e al eady p oposed he usage o he con usion ma ix (Congal on, 2001)
in assessing he accu acy and pe o mance o he model, we also compu e he con usion ma ix
by pe o ming c oss- abula ion o compa e he ac ual and simula ed maps o 2018. The con usion
ma ix which was gene a ed a e pe o ming c oss- abula ion was hen used o calcula e he
o e all accu acy, use accu acies, p oduce accu acies, and kappa coe icien .
In addi ion o ha , wo o he kappa coe icien s we e also compu ed o gain mo e in o ma ion on
he pe o mance o he model. The o he wo kappa coe icien s a e Khis o and Kloca ion.
Acco ding o Se na, (2011), Khis o is used o measu e he simila i ies in he numbe o cells
be ween simula ed and e e ence maps. In o he wo ds, his kappa is esponsible o measu ing
quan i a i e simila i y be ween wo compa ed maps. In ano he case, Kloca ion is used o measu e
he simila i ies in he spa ial dis ibu ion o classes bu does no di e en ia e be ween classes ha
a e close o dis an and i is independen o he o al numbe o cells pe class (Se na, 2011).
25
4.6. Calcula ion o Ecological isk indices
The inal s ep o ou analysis was o compu e ecological isk indices o each LULC map, as well
as o each dis ic o Zanziba island and hen compa ing hei esul s. This s age was done in
wo majo s eps. Fi s he landscape me ics (pa ch numbe and pa ch a ea) o each LULC maps
was calcula ed using LECOS plugin in QGIS 3.8, and hen he o mulas desc ibed in sec ion 4.6.1
below we e used o calcula e ecological isk indices o each map.
Ecological Risk index (ERI)
P o ide an indica o s o he nega i e en i onmen al impac s ha may occu o a e occu ing
due o one o mo e ex e nal ac o s (USEPA, 1992; Hakanson, 1980; Hunsake e al., 1990, X.
Zhang e al., 2013) .
Ma hema ically:
𝐸𝑅𝐼=∑𝐴𝑘𝑖
𝐴𝑘
𝑛
𝑖=1 𝑅𝑖
Whe e:
ERI: The ecological isk index o he isk a ea
Ak: is he o al a ea o k h egion
Aki = is he i h landscape a ea/class a ea
Ri: is he i h landscape/class loss index which can be calcula ed h ough o mula below.
𝑅𝑖=𝐹𝑖∗𝑆𝑖
Whe e: Fi, is he ecological agili y index which is e e ed as he abili y o a landscape o
esis he human dis u bance.
Acco ding o Zhang e al (2013), and he knowledge o ou s udy egion, he Fi alue o 5 o
buil up, 4 o wa e body, 3 o g ass land, 2 o a m land and 1 o o es we e used in his
s udy. Addi ionally, o an e ec i e esul , hese alues we e no malized be o e di ec ly being
used in calcula ions o ecological isk index.
Si is he landscape dis u bance deg ee index o i h landscape (Jin e al., 2019), which can also be
calcula ed ia a o mula.
𝑆𝑖=𝑎𝐶𝑖+𝑏𝑁𝑖+𝑐𝐷𝑖
26
Whe e:
Ci: Land scape agmen a ion, i e lec s he changes in landscape s uc u e and ecological
p ocess, 𝐶𝑖=𝑛𝑖
𝐴𝑘𝑖
Ni: Land scape isola ion, e e s o he deg ee o sepa a ion o pa ches in a gi en landscape ype,
𝑁𝑖=𝐴𝑘
2𝐴𝑘𝑖√𝑛𝑖
𝐴𝑘
Di: Landscape dominance index, desc ibe he dominance o pa ches in a gi en landscape,
𝐷𝑖=𝑄𝑖+𝑀𝑖+𝐿𝑖
3
ni: Is pa ch numbe o i h land scape, Qi: Ra io o he cell wi h i h pa ch and o al cell, Mi:
Ra io o he numbe o i h pa ches o o al pa ches and Li: Ra io o i h pa ch a ea o he o al
a ea. And a, b and c: ep esen he weigh o Ci, Ni and Di espec i ely whe e a + b + c = 1
(Zhang e al, 2013).

27
5. RESULTS
5.1. LULC changes 2003 - 2018
Figu e 5.1 below illus a e he LULC classi ied maps o he yea 2003-2009. As i can be seen,
he isual in e p e a ion o he classi ied images explo es ex ensi e changes in a ious land co e
classes in he s udy egion especially he apid expansion o buil up a ea as well as dec ease in
o es co e . The high inc ease in buil -up a ea is highly exposed in eas e n zone o he s udy
egion which a e nea o he u ban cen e o Zanziba island.
Figu e 5. 1: LULC classi ied maps o he yea 2003-2018
28
5.2. Accu acy assessmen
Accu acy assessmen o each land use map was pe o med in o de o ind classi ica ion e o s
and make he p oduced land co e maps become eliable and easily in e p e able by use s. Kappa
coe icien , o e all accu acy, use accu acy as well as p oduce accu acy we e all calcula ed and
he assessmen esul s we e summa ized in ( able 5.1, 5.2 and 5.3) below.
The assessmen esul s o each o he p oduced land co e maps p o ide an o e all accu acy
anging om 74% - 78%, and o e all kappa coe icien which is anging om 0.68 – 0.71. On
he o he hand, he use s and p oduce ’s accu acies compu ed o each o he classi ied maps we e
all abo e 65%. These esul s indica ing ha he classi ied images ha e me a good le el o
accu acy and hus hey a e sa is ying o he s udy analysis.
In all o he h ee classi ied images, he we land has shown a high use ’s accu acy (80% - 89%)
compa ed wi h o he land use classes. This implied ha he majo i y o hei pixels we e co ec ly
classi ied in hei espec i e classes. Howe e , in each classi ied image ei he a mland, g assland
o o es co e p o ides a minimum use s o p oduce s accu acy (63%-80%).
The maximum use ’s accu acies p o ided by he we land can be jus i ied by hei dis inc i e
cha ac e is ics in compa isons wi h o he LU classes. This cha ac e is ic makes hem easily being
disc imina ed by classi ica ion algo i hms agains o he land use classes du ing he classi ica ion
p ocess. Howe e , on ano he side, he lowes use s and p oduce ’s accu acies o a mland,
g assland and o es co e can be explained by hei spec al p ope y simila i ies among hem
(Mel ille, Luciee , & A yal, 2018).
o e all accu acy
76%
kappa
0.69
LULC classes
Buil -up
Fo es
g assland
a mland
We land
To al
Use accu acy
Buildup
32
0
5
3
2
42
76%
Fo es
2
37
6
0
1
46
80%
G assland
1
6
36
6
1
50
72%
Fa mland
5
5
3
31
0
44
70%
We land
0
2
0
0
16
18
88%
To al
40
50
50
40
20
200
P oduce s accu acy
80%
74%
72%
77%
80%
Table 5. 1: Con usion ma ix o LULC map o he yea 2003
29
O e all
accu acy
78%
kappa
0.71
LULC classes
Buil -up
Fo es
g assland
a mland
We land
To al
Use accu acy
Buildup
34
2
2
3
3
44
77%
Fo es
0
41
9
0
1
51
80%
G assland
1
3
35
8
0
47
74%
a mland
5
3
3
29
0
40
73%
We land
0
1
1
0
16
18
89%
To al
40
50
50
40
20
200
P oduce s
accu acy
85%
82.00%
70%
72%
80%
Table 5. 2: Con usion ma ix o LULC map o he yea 2009
O e all accu acy
75%
kappa
0.68
LULC classes
Buil -up
Fo es
g assland
a mland
We land
To al
Use accu acy
Buildup
33
1
1
4
2
41
80%
Fo es
1
39
6
3
0
49
79%
G assland
1
6
34
6
1
48
70%
a mland
5
1
9
26
0
41
63%
We land
0
3
0
1
17
21
80%
To al
40
50
50
40
20
200
P oduce s accu acy
82%
78.00%
68%
65%
85%
Table 5. 3: Con usion ma ix o LULC map o he yea 2018
30
5.3. LULC changes 2003 - 2018
The s a is ical esul s co esponding o LULC change in he s udy a eas (Table 5.4) indica ing
ha , he e is an ex ensi e inc ease in he buil -up a ea as equi alen o he dec ease in o es co e .
The buil -up a ea o Zanziba island has been expanding om 4132.44 Hec a e in he yea 2003
o 7201.35 Hec a e in 2018. These a eal changes in he buil -up a ea make up o 42.6% inc ease
in cons uc ion land o only 15 yea s’ (2003-2018) pe iod (2.84% inc ease annually).
The Fa mland/ag icul u al land has also shown a p og essi e expansion wi hin hese 15 yea s o
he s udy, in which 31.7% (2.1% annually) o ag icul u al land we e inc eased.
Fo he o es co e and we land, he ends on hei land co e changes ha e shown a
con inuously dec easing, in which 15.8% o o es co e (1.05% annually) and 24.6% o we land
(1.64% annually) we e disappea ed.
Howe e , in he case o g assland, he end in i s LULC changes does no show a smoo h
a ia ion. This is because, in he i s 6 yea s (2003-2009), he g ass co e o he s udy a ea has
been dec eased by 4.5%, ollowed by inc easing o 7.48% o he nex 9 yea s (2009 – 2018).
LULC
classes
A ea (ha)
(2003)
A ea (ha)
(2009)
A ea ( (2018)
% changes
(2003-2009)
% changes
(2009-2018)
% changes
(2003-2018)
Buil -up
4132.44
5081.94
7201.35
18.68
29.43
42.62
Fo es
73329.39
69460.56
61692.03
-5.28
-11.18
-15.87
Fa mland
22171.77
27669.15
29206.17
24.79
5.26
31.73
G assland
56569.41
54107.73
58484.43
-4.55
7.48
3.27
We land
1925.55
1809.18
1544.58
-6.43
-17.13
-24.66
Table 5. 4: LULC a eal s a is ics om 2003 -2018
This apid LULC changes o se e al land co e classes wi hin he s udy egion could be a ibu ed
by he imp ope way o managing he land including he high a e o in o mal se lemen , casual
a ming me hods as well as he highe le el o de o es a ion ac i i ies in Zanziba (M. O.
Kukkonen e al., 2018).
37
The ex eme scena io shows a e y high inc ease in ERI end compa ed o hose o business as
usual and conse a ion scena io (Table 5.10). Howe e , i has o be no ed he e ha , al hough in
ex eme scena ios he e was no cons ain s ha was employed, i ’s ERI is mo e likely o be
applicable in Zanziba e en mo e han ha o business as usual. This is due o he ac ha in
Zanziba he de elopmen and cons uc ion o buildings in a andom way and wi hou ollowing
es ic ions and go e nmen egula ions a e one among he common and majo p oblem acing
u ban planning and hus hey make no much signi icance in he land change esul s ob ained by
employing cons ain in e e y p o ec ed a ea.
In summa y, he o e all ERI o he s udy a ea shows an inc easing end om 2003 o 2027.
Whe eas, he e is also a signi ican change (mos ly inc easing) in he numbe o pa ches,
agmen a ion and sepa a ion indices as well as a con inuous dec ease in he g ea es pa ch a ea
o he o es , a mland, and g assland.
Yea /Scena io
O e all ERI
% Changes
2003
0.0714
-
2009
0.0867
17.7
2018
0.0957
9.4
BAU
0.1020
6.2
EXTREME
0.1050
8.9
CONSERVATION
0.1002
4.6
Table 5. 10: O e all Ecological isk index changes 2003 – 2027
Figu e 5. 5: T ends o o e all ERI om 2003 - 2027

38
5.5.3. Dis ibu ion o ERI pe dis ic
While compa ing he dis ibu ions o ERI a a dis ic le el (Figu e 5.6 and Table 5.11), i appea s
ha he dis ic s U ban-wes , No h A and No h B expe iences he high and p og essi ely
inc eases in hei ERI alues, while he ERI o he U ban dis ic s seems o be s able.
The ex ensi e inc eases in ERI o hese h ee dis ic s could be highly in luenced by he high
a e o casual ag icul u al ac i i ies, ou ism ac i i ies as well as in o mal housing in hese
egions.
In he case o he h ee u u e scena ios, he esul s show ha he ex eme scena io p o ides he
highe ERI inc eases in almos all dis ic s o Zanziba especially in No h A and No h B whe e
he inc ease in ERI alues co esponding o he ex eme scena io a e 23.5% and 17.92
espec i ely. The conse a ion scena io in o he case shows he ai ERI esul s in almos i e
dis ic s o Zanziba excep o he No h A dis ic which show he highe inc eases in ERI o
all o he 2027 scena ios.
Dis ic
T end o ERI Change (%)
2003-2009
2009-2018
2018-2027
BAU
2018-2027
EXTREM
2018-2027
CONSERVATION
No h A
16.63
8.95
18.51
23.45
17.13
No h B
9.89
14.78
13.51
17.92
2.79
Cen al
10.37
4.39
10.82
8.64
1.82
Sou h
10.37
10.63
10.94
8.35
3.67
Wes
14.57
23.41
5.39
11.61
6.93
U ban
-1.35
5.27
0.24
2.19
0.49
Table 5. 11: ERI Changes by dis ic 2003-2027
39
Figu e 5. 6: T end o ERI pe dis ic 2003 - 2027
40
6. DISCUSSION
This s udy was employed o assess ecological isk condi ions in Zanziba based on land co e
change, wi h he ocus o p o iding a holis ic unde s anding o land co e dynamics and hei
en i onmen al impac s along wi h p e en ing unmanaged g ow h and andom de elopmen o
in o mal housing and in as uc u e. Based on Random Fo es Classi ie , Mul i-Laye Pe cep on
(ANN) and Ma ko Chain, we success ully assessed he end o land-use dynamics om 2003-
2018 i s and hen he land use maps o 2027 was p edic ed. LECOS plugin in QGIS 3.8 was
e ec i ely applied o calcula e landscape me ics in land use maps and hen employed hem o
calcula e ecological isk indices o he landscape. These indices including sepa a ion, agili y,
dominance, loose as well as o e all ecological isk index o he landscape.
Du ing he i s s ages o analyzing land-use dynamics, we ha e ealized ha Zanziba Ci y has
expe ienced a end o apid land-use changes and ex ensi e buil -up expansion mos ly in a eas
nea exis ing buildings, and some o he coas al zones. The esponse dis ance o he buildings and
dis ance o coas a iable suppo s his obse a ion as hey p o ide he highe C amme ’s alues
ensu ing ha hese a iables ha e a g ea in luence on land co e dynamics in Zanziba .
I he cu en end con inues, he buil -up expansion o Zanziba ci y will be expanded o mo e
han 40% by 2027. The La ge pa o ag icul u al and o es ed land has al eady been agmen ed
o housing pa cels. And because o hese, he nega i e en i onmen al e ec s ele an o land
esou ces, such as loss o na u al o es s, open c opland, and we lands ha e been al eady being
highly des oyed in Zanziba (M. H. Ali & Sulaiman, 2006). This is somewha ala ming ha he
go e nmen should en o ce es ic ions and s ong land policies lea ing he emaining land co e
classes o s op being u he des oyed.
The analysis esul s gi e no signs indica ing ha hese land-use changes and ex ensi e buil -up
expansion would a leas decline in he u u e. And his is possibly caused by he poo quali y o
housing and minimum go e nmen e o s o en o ce he op imal usage o land esou ces in
Zanziba island (Ameyibo e al., 2003).
While analyzing he o e all ecological isk indices o he landscape, he esul s sc eened ha , he
o e all ERI o Zanziba Ci y has been cons an ly g own om 2003 onwa d. This end is pa allel
o he inc ease in he numbe o smalle pa ches o some land co e classes, ela i e o he
dec easing in hei la ges pa ch a eas.
41
The obse a ion o he u u e scena ios p o ide he wo s ecological isk indices o he ex eme
whe eas conse a ion scena io p o ides a li le ai esul s. The d as ic ecological isk sco es
p o ided by ex eme scena io, sugges ed ha , he land use es ic ions in Zanziba should be
p ope ly espec ed, a leas by p ope ly u ilizing he al eady exis ing land policies and es ic ions.
Finally, i would be e y impo an o highligh ha , in his s udy we ha e assessed ecological
isk indices o Zanziba island wi h land co e change using ee sa elli e da a. This p ocess
equi ed a consis en and accu a e land co e da a o he pu pose o p o iding eliable and
accu a e in o ma ion. Howe e , i was a bi challenge in acqui ing ee sa elli e images wi h
desi ed s anda d and a desi ed ime. This is due o he geog aphical egion o Zanziba island
making mos o hei sa elli e images being co e ed wi h cloud. In ha sense, i akes a much
ime o sea ch and acqui e he needed sa elli e da a, and e en hough he image o 2018 ha was
ob ained was no in e y good quali y and con ain some scanned lined which somehow a ec ed
he analysis esul s. Howe e , in u u e hese esul s can be imp o ed by using mo e accu a e and
upda e da a, as well as inco po a ing ex ensi e land co e change d i e s.
42
7. CONCLUSIONS AND RECOMMENDATIONS
The indings in his esea ch suppo he e idence o he ecen s udy which ound ha he apid
land-use changes in Zanziba ha e imposed an in ensi e deg ada ion in he ecosys em o Zanziba
(A S aeh , 2018). The main d i e s behind his in ensi e deg ada ion a e inc easing in
uncon olled and poo ly managed in o mal housing, high a e o casual a ming and imp o ised
plan in he ou ism sec o (WB, 2019). E idence has been clea ly exposed by inc easing he
agmen a ion index, sepa a ion index, loss index as well as o e all ERI o he en i e landscape.
In o de o educe such kind o h ea s, mo e sys ema ic app oaches in he ecological assessmen
a e equi ed. Coope a i e esea ch among esea ch g oups, land planne s, and all o he
s akeholde s including ou ism sec o s should be highly en o ced as a ool o moni o and
ecommend a long- e m plan o sus ainable ecosys ems in Zanziba .
In u u e scena ios, he indings ha e p o en ha disobeying land policies and egula ions can
in luence a d as ic shock o he ecological condi ions o Zanziba in he u u e. This has been
p o en by he esul s o an ex eme scena io which was e y wo s . Conse a ion scena io o
somehow had shown li le in luence on di ec ing u u e land co e changes and ecological isk
con ol, bu howe e , he esul s we e only mode a e and he e o e i is eally impo an o he
go e nmen o ake a special e o on se ing up new land-use app oaches such as p omo ing he
densi ica ion o e ical buildings a he han elying in one- loo ho izon al buildings.
In gene al, all o he indings in his s udy can p o ide use ul insigh s o land-use planne s and
policymake s ega ding he cu en ends and u u e p ojec ion o land co e changes in
Zanziba , he ac o s d i ing hese changes as well as he e ec ha hey ha e imposed in hei
ecological heal h. This can help he esponsible au ho i ies on se ing up he p ope ules and
egula ions on land use con ol.
The s udy also assessed he ecological heal h condi ions o he Zanziba islands in h ee di e en
scena ios. In his case, he esul s can se e as he basic no ion in explo ing he sus ainabili y o
he landscape s uc u e o he Zanziba island as well as i s ecological heal h secu i y unde
a ious land-use p ac ices. This can con ibu e o he designa ion o he app op ia e s a egies
owa d he land use managemen so ha a sys ema ic balance be ween economic and sus ainable
ecosys ems can be main ained.

43
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