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E ec i eness o legisla i e ools o s op biological in asions:
eshwa e u les’ in asion in Eu ope as a s udy case
João Ra o1,2,3 , Ped o B andão1,2,3 , Ma alda Gama1,2,3 , Filipe Banha1,2,3 , Ped o Anas ácio1,2,4
1 MARE – Ma ine and En i onmen al Sciences Cen e, É o a, Po ugal
2 ARNET – Aqua ic Resea ch Ne wo k, É o a, Po ugal
3 IIFA - Ins i u e o Resea ch and Ad anced T aining, Uni e si y o É o a, Palácio do Vimioso, La go Ma quês de Ma ial a, 7002 - 554, É o a, Po ugal
4 Depa men o Landscape, En i onmen and Planning, Uni e si y o É o a, Rua Romão Ramalho, 59, É o a, Po ugal
Co esponding au ho : João Ra o ([email p o ec ed]a.p )
Copy igh : © João Ra o e al.
This is an open access a icle dis ibu ed unde
e ms o he C ea i e Commons A ibu ion
License (A ibu ion 4.0 In e na ional – CC BY 4.0).
Resea ch A icle
Abs ac
In asi e species pose signi ican h ea s o biodi e si y, human heal h, and economic sys ems. F esh-
wa e u les a e popula as pe s, bu when eleased o allowed o escape in o he wild, hey can be-
come in asi e. A p ominen example is he ed-ea ed slide T achemys sc ip a, which is ecognized as a
globally in asi e species. Legisla i e ools, such as he Eu opean Union Regula ion 1143/2014 on he
p e en ion and managemen o in asi e alien species, aim o comba hese h ea s. This amewo k
includes he implemen a ion o Commission Implemen ing Regula ion 1141/2016, which banned
he ade o lis ed in asi e species, including T. sc ip a. This s udy e alua es he e ec i eness o Reg-
ula ion 1143/2014 on T. sc ip a in asion and i s consequences on o he eshwa e u le in asions,
using da a om he CITES da abase and he GBIF pla o m. While T. sc ip a impo s in o he EU
ceased a e 2016, he species con inues o es ablish and expand in he wild. This sugges s ha he
ade ban had minimal impac on al eady es ablished popula ions, highligh ing he need o addi ion-
al measu es o educe and con ol i s sp ead. Simul aneously, impo s and eco ds o o he eshwa e
u le species ha e isen, indica ing a shi in ade dynamics. These species a e inc easingly being
in oduced, po en ially exace ba ing he biological in asion p oblem. Despi e limi a ions inhe en
o CITES and GBIF da a, ou indings sugges ha he cu en Eu opean legisla ion has no been
e ec i e in mi iga ing T. sc ip a in asions and may ha e unin en ionally con ibu ed o he in oduc-
ion o o he in asi e u les. We ecommend ha he Eu opean Union de elop in asi e species lis s
ailo ed o each biogeog aphic egions o Eu ope o enhance he e ec i eness o legisla ion.
Key wo ds: Exo ic species, managemen , pond u le, egula ions, e apin
In oduc ion
The global ade o exo ic animals, including bo h in e na ional and domes ic
ade, is a e y luc a i e business which, accoun ing only o he legal ade, p o-
ides e enues o millions o dolla s (Lockwood e al. 2019). Globally, some o he
mos aded g oups a e bi ds (o de s Psi aci o mes and Passe i o mes) and ep-
iles (o de s Squama a and Tes udines) (Bush e al. 2014). Ne e heless, domes ic
ma ke s, non- adi ional ma ke s (such as websi es and social media pages), and
illegal ma ke s emain undocumen ed o poo ly documen ed, which makes global
assessmen s o ade di icul (Lockwood e al. 2019). On he o he hand, “legal”
Academic edi o :
Tammy Robinson-Smy he
Recei ed:
2 Decembe 2024
Accep ed:
9 Ap il 2025
Published:
7 Oc obe 2025
Ci a ion: Ra o J, B andão P, Gama
M, Banha F, Anas ácio P (2025)
E ec i eness o legisla i e ools o
s op biological in asions: eshwa e
u les’ in asion in Eu ope as a
s udy case. In: Anas ácio P, Ribei o
F, Chainho P (Eds) In asions in
Aqua ic Sys ems. NeoBio a 102:
313–329. h ps://doi.o g/10.3897/
neobio a.102.143330
NeoBio a 102: 313–329 (2025)
DOI: 10.3897/neobio a.102.143330
Ad ancing esea ch on alien species and biological in asions
A pee - e iewed open-access jou nal
NeoBio a
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João Ra o e al.: E ec i eness o legisla i e ools o s op biological in asions
in e na ional ade is well documen ed. Fo example, he in e na ional ade o
exo ic species ha a e h ea ened is egula ed by he Con en ion on In e na ional
T ade in Endange ed Species o Wild Fauna and Flo a (CITES). Depending on
i s h ea ened s a us, a species ade may only be au ho ised unde special ci -
cums ances (Appendix I, CITES 2025), may be subjec ed o s ic ules no o
endange he species (Appendix II, CITES 2025) o may e en ha e special ules
o speci ic pa ies (Appendix III, CITES 2025). Con en ion pa ies a e obliged o
epo impo s and expo s o he species included in he CITES appendices, hese
a e ga he ed in an in e na ional da abase (h ps:// ade.ci es.o g/). Howe e , many
species a e no egula ed by CITES because hey a e no conside ed h ea ened and
hus emain eely aded (Bush e al. 2014). The need o documen species ade is
no only ela ed o iden i ying and egula ing he ade o endange ed species bu
also o iden i ying and p e en ing he in oduc ion o exo ic species (Gippe and
Be elsmeie 2021). The comme cial success o a species can inc ease i s in asi e
po en ial, as he mos aded species a e also he ones wi h he po en ial o being
mos in oduced ou side hei na i e ange (Gippe and Be elsmeie 2021).
Like many exo ic animals kep as pe s, eshwa e u les (FTs) a e o en e-
leased o he wild when hey ge bigge and olde (Banha e al. 2019). As a esul ,
FTs ha e become in asi e wo ldwide and, in some cases, wi h g ea success, as
he ed-ea ed slide (T achemys sc ip a THUNBERG, 1792) (Eu opean En i on-
men Agency 2012). This species has been in oduced o i ually e e y con inen ,
mainly h ough he pe ma ke , and has se e e impac s on biodi e si y and human
heal h (Eu opean En i onmen Agency 2012). A he biodi e si y le el, T. sc ip a
may impac na i e FTs, by compe ing o ood and he mo egula ion si es, dis-
playing agg essi e beha iou , and/o disease ansmission (Polo-Ca ia e al. 2014;
Ra o e al. 2024b). Due o hei oppo unis ic eeding beha iou and hei die a y
on ogenic shi , T. sc ip a eeds on a a ie y o animal and plan species, which
has implica ions o aqua ic communi ies (Pé ez-San igosa e al. 2011; Eu opean
En i onmen Agency 2012). Rega ding human heal h, T. sc ip a is a well-known
ese oi o Salmonella spp., which has caused se e al pe u le-associa ed salmo-
nellosis ou b eaks in he USA (Basle e al. 2015). These u les may also ha bou
o he zoono ic disease agen s, like Lep ospi a sp. and Chlamydia spp., among o he s
(Mi u a e al. 2017; Bonacina e al. 2021).
To educe he impac s and minimise in oduc ion isk o hese species, se e al
ac ions may be aken such as en i onmen al educa ion, p e en ion, con ol and
e adica ion o es ablished popula ions. One o he possible ac ions is he c ea ion
o legisla ion o p e en he in oduc ion o non-na i e and in asi e species. Such
legisla ion, ypically including species’ blacklis s, may p ohibi he ade, he ep o-
duc ion, and he main enance unde cap i i y o ce ain non-na i e and in asi e
species ha a e pa icula ly damaging o he ecosys ems, o in some cases, ha
migh be disease ec o s (Simbe lo 2006; Zamo a-Ma ín e al. 2023). Howe -
e , hese blacklis s (1) o en include some, bu no all, o he al eady in oduced
species in an a ea/coun y, (2) do no p e en he sp ead o es ablished species o
he subs i u ion o hei ade by simila species, and (3) do no in ol e any inan-
cial suppo o hei implemen a ion (Simbe lo 2006; O icialdegui e al. 2023;
Zamo a-Ma ín e al. 2023). To complemen he blacklis s, some coun ies ha e
c ea ed whi elis s, i.e. lis s o au ho ized species o ade, which may be associa ed
wi h a isk analysis (Simbe lo 2006). In he Eu opean Union, in 1996 he Coun-
cil Regula ion (EC) 338/97, which egula ed he ade o some exo ic species was
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João Ra o e al.: E ec i eness o legisla i e ools o s op biological in asions
c ea ed, bu only included one FT, T. sc ip a. Howe e , he implemen a ion o his
egula ion alone was insu icien o hal he sp ead o in asi e species. To add ess
his, a subsequen egula ion, Regula ion 1143/2014, was in oduced. I includes
a lis o non-na i e species o Union Conce n whose ade is p ohibi ed by imple-
men ing egula ion 1141/2016. Howe e , his egula ion ini ially lis ed only one
eshwa e u le (FT). I is wo h no ing ha he lis o species o Union conce n
may di e om hose es ablished a he na ional le el, i.e. he lis s o species o
na ional conce n as pe A icle 12 o Regula ion 1143/2014. Fo example, he Po -
uguese blacklis includes i e non-na i e u les (Mac ochelys emminckii, Chelyd a
se pen ina, Pseudemys spp., G ap emys spp. and T achemys spp.) while he Spanish
blacklis includes h ee non-na i e eshwa e u les (Ch ysemys pic a, Pseudemys
peninsula is and T achemys sc ip a) (Dec e o-Lei n.o. 92/2019, 2019; Real Dec e o
216/2019, 2019).
The adi ional ield moni o ing o non-na i e and in asi e species may be ex-
emely di icul and ime-consuming, and some p ojec s and s udies a e s a ing
o inco po a e da a om ci izen science p ojec s (Johnson e al. 2020). Al hough
i has some cons ain s, ci izen science may be an e ec i e way o ga he long- e m
and la ge amoun s o species dis ibu ion da a (Johnson e al. 2020; La son e al.
2020). Fo in asi e species moni o ing, i may be pa icula ly impo an o eco d
he i s de ec ion o a species, o upda e he dis ibu ion o non-na i e/in asi e
species and o use dis ibu ion da a o p edic u u e dis ibu ion anges (Johnson
e al. 2020). Some p ojec s a e species-speci ic (Johnson e al. 2020; La son e al.
2020), which may limi he de ec ion o di e en non-na i e species. The Global
Biodi e si y In o ma ion Facili y (GBIF) is an in e na ional da abase ha compiles
da a in o ma ion om mul iple da a sou ces, including om se e al ci izen science
p ojec s, o many o he wo ld’s species. This open-access da abase may be used o
moni o non-na i e and in asi e species (I ano a and Shashko 2021).
To e alua e he impac o legisla ion in p e en ing and mi iga ing he in asi e
species in oduc ions associa ed wi h he pe ma ke , we used he eshwa e u -
le’s in asion in Eu ope as a case s udy. Namely, we ocused on he e ec i eness
o he 1143/2014 Eu opean Union egula ion on T. sc ip a in asion, included in
he implemen ing egula ion 1141/2016, compa ing EU wi h non-EU coun ies.
We analyzed T. sc ip a numbe o impo s and eco ds in he wild o all Eu opean
coun ies, bo h EU membe s and non-EU membe s. Simila ly, we also ga he ed
impo s and eco ds in he wild, o o he species o FTs. We expec ed o ind a
educ ion in he impo s o T. sc ip a along wi h a s abiliza ion o educ ion o T.
sc ip a eco ds, po en ially accompanied by an inc ease in he impo s and eco ds
o o he FTs, pa icula ly in EU membe s a es.
Me hods
Da a acquisi ion and da ase s
Impo a ion da a was acqui ed om he CITES da abase on Feb ua y 2nd 2024.
We chose o only use CITES lis ed species because his is he longes unning
impo da ase , using da a om 1998 un il 2022. O he da a on in e na ional
ade o FTs is sca ce. We s a ed in 1998 because he manda o y epo o CITES
lis ed species o EU coun ies only s a ed in June 1997 (Council Regula ion (EC)
338/97 1996). T achemys sc ip a is no lis ed as an endange ed species by any o
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João Ra o e al.: E ec i eness o legisla i e ools o s op biological in asions
he appendices o CITES; howe e , due o i s in asi e s a us, i was added o he
ansc ip ion o CITES o he EU legisla ion, and he e o e, his species’ impo a-
ions a e also epo ed and added o he CITES da abase. We did no inco po a e
any da a o es ima es om domes ic and illegal ade o non-na i e eshwa e
u les. F om he CITES da ase , we only e ie ed da a om Eu opean coun ies
and excluded any impo s o dead specimens, animal pa s, and eggs, lea ing only
li e ju enile and adul u les. All impo a ion pu poses, om pe o esea ch, we e
included in he e ie ed da ase . The o al numbe o u les impo ed o each
pu pose can be consul ed in Suppl. ma e ial 1: able S1. To s anda dize all im-
po a ion da a, impo s epo ed in kg we e di ided by he mean epo ed species
weigh o ge he numbe o li e specimens. We g ouped all impo s o o he FTs
in a single a iable.
On Feb ua y 15 h 2024, we e ie ed om GBIF all Eu opean obse a ion e-
co ds o all he CITES lis ed eshwa e u le species o each yea o he same
pe iod (1998–2022). We excluded da a ha came om ossil eco ds, p ese ed
specimens, ma e ial ci a ions, and sample ci a ions, lea ing only li e specimens’
obse a ions. Like o he CITES da ase , we sepa a ed T. sc ip a obse a ions and
g ouped he emaining FTs’ obse a ions in o a single a iable, o each yea and
coun y. The wo da ase s we e hen joined by he co esponding yea and coun y.
S a is ical analysis
Fo he modeling app oach, he spa io- empo al a ia ion o impo and p esence
in he wild da a o eshwa e u les was explo ed using linea mixed models
(LMMs). LMMs we e used because adi ional s a is ical eg ession me hods a e
no adequa e when a iables ha e non-linea ela ionships, as is expec ed o mos
biological con ex s. LMMs ha e also been widely used o modeling da a on in a-
si e species wi h a wide dis ibu ion and spa ial/ empo al dependence, aking in o
accoun andom ac o s (Thiele and Ma kussen 2012; Cos a 2014). Fo each o
he models, he esponse a iables we e modelled using Pe iod (be o e s a e he
egula ion 1143/2014), EU membe ship, Coun y popula ion, T achemys sc ip a
impo s and eco ds and o he FTs’ impo s and eco ds (i.e. ixed e ec s). The
GBIF eco ds we e agg ega ed as he o al numbe o T. sc ip a eco ds pe coun y
pe yea . Simila ly, o o he FTs, he GBIF eco ds we e calcula ed as he o al
numbe o non-T. sc ip a FT eco ds pe coun y pe yea . Yea , GDP, Coun y
a ea and Coun y we e ea ed as andom ac o s o conside possible a ia ions in
e ms o he legisla ion en o ced. Fo he eco ds models we also used he numbe
o GBIF eco ds o es udines species in Eu ope as andom ac o . The use o an-
dom ac o s allowed o accoun o he a iabili y no explained by he ixed e ec s.
Fo he a iable Pe iod we conside ed wo pe iods: Be o e 2016 and A e 2016.
We chose 2016 because i was he yea o publica ion o implemen ing egula ion
1141/2016, which classi ied T. sc ip a as in asi e species o Union conce n and
p ohibi ed i s ade in he EU. Fo each yea , we classi ied he coun ies as EU o
non-EU membe s acco ding o hei da e o en y o he EU; his esul ed in a di -
e en numbe o coun ies in each yea o bo h coun ies’ g oups (Suppl. ma e ial
1: able S2). To check o mul icollinea i y and edundancy o a iables, ollow-
ing Fielding and Hawo h (1995), a Spea man co ela ion analysis was conduc ed.
Only Yea and numbe o CITES lis ed species, as well as Coun y and Coun y
a ea showed a high co ela ion coe icien ( > 0.9), and he e o e we excluded he
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João Ra o e al.: E ec i eness o legisla i e ools o s op biological in asions
numbe o lis ed CITES species and Coun y a ea om ou analysis (Suppl. ma e-
ial 1: ig. S1). The bes model was ob ained by conside ing models wi h di e en
a iable combina ions and selec ing he bes i model using Akaike in o ma ion
c i e ion (AIC), wi h he mos pa simonious models p esen ing he smalles AIC
(goodness-o - i measu e) (V ieze 2012). Pos -hoc compa isons a e LMM we e
pe o med o es ima e pai wise di e ences be ween he ca ego ical a iables using
Tukey-HSD es s including p- alue co ec ions o mul iple compa isons, sum-
ma ized in Suppl. ma e ial 2. A s a is ical signi icance le el o 0.05 was conside ed
in all es p ocedu es. S a is ical analyses we e pe o med wi hin he R So wa e
(Ve sion 1.1.463) (Posi eam. 2022) using he “mgc ” (Wood 2011), “ggplo 2”
(Wickham 2016) and “lme4” (Ba es e al. 2015) packages.
The limi a ions o using he CITES da abase and GBIF eco ds o assess he e -
ec i eness o Regula ion 1143/2014, as well as hei implica ions o o he exo ic
eshwa e u les, a e discussed in Suppl. ma e ial 3.
Resul s
The op 10 mos aded species in Eu opean coun ies acco ding o CITES and he
op 10 species wi h mos eco ds on GBIF, excluding T achemys sc ip a, a e iden-
i ied in Table 1. Fi e species – G ap emys pseudogeog aphica, Mau emys ee esii,
Mau emys sinensis, G ap emys ouachi ensis, and Pelodiscus sinensis – ank among he
mos equen ly aded and eco ded species.
The bes T achemys sc ip a impo s model was composed by pe iod, EU mem-
be ship and he in e ac ion be ween pe iod and EU membe ship, wi h he in e -
ac ion p esen ing he only signi ican esul (p- alue = 0.0287, Table 2). Tukey
es esul s showed signi ican di e ences be ween T. sc ip a impo s in EU and
non-EU coun ies be o e he legisla ion and be ween he pe iod be o e and a e
he legisla ion o EU coun ies (Suppl. ma e ial 2, bu also isible in Fig. 1A).
Da a on annual impo s show ha T. sc ip a impo s s a o dec ease om 1998
un il 2000 when hey s a ed o s abilize a low numbe s and comple ely s opped
in 2016. By opposi ion o he FTs’ impo s emained s able un il 2004 when hey
s a ed o inc ease, wi h a peak in 2018 o EU coun ies and a peak in 2021 o
non-EU coun ies (Suppl. ma e ial 1: ig. S2), despi e o he in luence o T. sc ip a
impo s on he o he FTs’ impo s being non-signi ican (Table 2). The main Eu-
opean impo e s we e Spain, Po ugal, and Belgium (Fig. 2A).
Fo T. sc ip a eco ds he bes model was he one ha inco po a ed pe iod and
EU membe ship. Howe e , none o hese we e signi ican in hei own igh (Table
2). T. sc ip a eco ds inc eased since 1998 o bo h coun y g oups, bu wi h a sligh
s abiliza ion in he la e yea s o non-EU coun ies. This di e s om T. sc ip a
impo s, which had a huge numbe o impo a ions be ween 1998 and 2000 and
s opped a e 2016 (Fig. 1A, B; Suppl. ma e ial 1: ig. S2). O e all, he inc ease in
T. sc ip a eco ds was co ela ed wi h an inc ease in all es udines eco ds in Eu ope
( 2= 0.9, Suppl. ma e ial 1: igs S1, S3). When looking a he di e ence be ween
he EU membe s and non-membe s, T. sc ip a eco ds had inc eased in bo h coun-
ies’ g oups, al hough he o al numbe o eco ds was di e en , being highe in
EU coun ies (Fig. 1A, B). The coun ies wi h he la ges numbe o eco ds pe
km2 we e Belgium, The Ne he lands, Luxembou g, and Spain, which all belong o
he EU (Fig. 2B). O e all, T. sc ip a eco ds we e highe a e 2016, compa ed o
he p e ious pe iod, o EU coun ies (Table 2, Fig. 1B).
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João Ra o e al.: E ec i eness o legisla i e ools o s op biological in asions
Table 1. Top 10 mos impo ed and op 10 mos eco ded eshwa e u les om 1998 o 2022 o
all Eu ope (combined EU and Non-EU coun ies), apa om T achemys sc ip a, anked by dec eas-
ing o de . Species included in bo h lis s a e in bold.
Mos aded species on CITES Mos eco ded species on GBIF
Family Species Family Species
Emydidae G ap emys pseudogeog aphica Emydidae G ap emys pseudogeog aphica
Geoemydidae Mau emys ee esii Emydidae Pseudemys concinna
Geoemydidae Mau emys sinensis Chelyd idae Chelyd a se pen ina
Emydidae G ap emys ouachi ensis Emydidae Pseudemys nelsoni
Pelomedusidae Pelomedusa sub u a Emydidae G ap emys ouachi ensis
T ionychidae Pelodiscus sinensis Geoemydidae Mau emys sinensis
Pelomedusidae Pelusios nige Emydidae Ch ysemys pic a
Emydidae G ap emys e sa Geoemydidae Mau emys ee esii
Podocnemididae Podocnemis uni ilis Emydidae Pseudemys ub i en is
Pelomedusidae Pelusios cas aneus T ionychidae Pelodiscus sinensis
Table 2. Resul s o he selec ed LMM o explain a ia ion on he impo s and eco ds o T achemys
sc ip a and o he FTs pe squa ed kilome e and species. All a iables included in he models we e
signi ican .
Model (n = 2070) Model e m Fixed e ec s Random e ec s
Es ima e SE P- alue Va iance SD
T achemys sc ip a
impo s
Pe iod: Be o e 2016 -11.84 100.225 0.9059 – –
EU: Yes 1.069 68.9202 0.9876 – –
Pe iod × EU 178.303 81.5145 0.0287 – –
(1|Yea ) – – – 33272 5168
(1|Coun y) – – – 3780 182.41
T achemys sc ip a
eco ds
Pe iod: Be o e 2016 -0.7396 0.8611 0.3903 – –
EU: Yes -0.5924 1.3871 0.6693 – –
(1|All eco ds) – – – 122579.46 350.114
(1|Yea ) – – – 0.000e+00 0.0000
(1|Coun y) – – – 118.40 10.881
(1|GDP) – – – 0.000e+00 0.0000
O he FTs’ impo s Pe iod: Be o e 2016 3.293e+02 2.080e+03 9.001e-01 – –
EU: Yes 1.088e+04 3.131e+03 5.216e-04 – –
Pe iod x EU -1.138e+04 2.641e+03 1.631e-05 – –
Impo s T achemys
sc ip a
-1.615e+00 9.501e-01 8.904e-02 – –
(1|Yea ) – – – 3412347 0.08907
(1|Coun y) – – – 182548370 1847.3
(1|GDP) – – – 185035 430.2
O he FTs’ eco ds Impo s o he 7.735e-06 1.841e-06 2.66e-05 – –
(1| All eco ds) – – – 2.024e+02 14.22653
(1|Yea ) – – – 3.159e-03 0.05621
(1|Coun y) – – – 0.000e+00 0.00000
(1|GDP) – – – 6.304e-04 0.02511
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João Ra o e al.: E ec i eness o legisla i e ools o s op biological in asions
Figu e 1. T achemys sc ip a annual a ia ion o impo s and eco ds in na u e, be ween 1998 and 2022. Red line- EU membe s a es. Blue
line- non-EU coun ies A o al impo s by yea in CITES da abase B o al eco ds in GBIF pe yea .
Figu e 2. T achemys sc ip a impo s and eco ds in Eu ope (bo h EU and Non-EU coun ies), combined be ween 1998 and 2022 A o al
impo s pe coun y pe squa e kilome e B o al eco ds pe coun y pe squa e kilome e. Inc easing numbe o impo s (A) and (B) om
ligh e o da ke colou s. G ey colou co esponds o absen da a.
The bes model o o he FTs’ impo s included Pe iod, T. sc ip a impo s, EU
membe ship and he in e ac ion be ween he pe iod and EU membe ship. Fo his
model only T. sc ip a impo s and Pe iod we e non-signi ican (p- alue = 0.0967).
The impo o o he FTs eached i s maximum in 2019 (Fig. 3A; Suppl. ma e ial
1: ig. S2). Be o e 2005, he impo s o o he FTs we e e y low. Like in he o he
models, he numbe o impo ed u les was highe in EU coun ies (Table 2 and
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Figu e 3. O he non-T achemys sc ip a eshwa e u les’ annual a ia ion o impo s and o eco ds in na u e. Red line- EU membe
s a es. Blue line- non-EU coun ies A o al impo s by yea in he CITES da abase B o al eco ds in GBIF pe yea .
Figu e 4. O he non-T achemys sc ip a eshwa e u le impo s and eco ds in Eu ope (bo h EU and Non-EU coun ies), combined
be ween 1998 and 2022 A o al impo s pe coun y, pe squa e kilome e, pe CITES lis ed species B o al eco ds pe coun y, pe squa e
kilome e. Inc easing numbe o impo s (A) and (B) om ligh e o da ke colou s. G ey colou co esponds o absen da a.
Fig. 4A). The coun ies wi h he la ges numbe o impo s we e Po ugal, I aly and
Luxembou g (Fig. 4A). The Tukey es was signi ican o all in e ac ions excep o
non-EU coun ies be ween, be o e and a e 2016 (Suppl. ma e ial 2).
Finally, ega ding o he FTs’ eco ds, he bes model only included he a iable
o o he FTs’ impo s, and i was signi ican (p- alue = 2.66e-05, Table 2). The
numbe o o he FTs’ eco ds was small, wi h a subs an ial inc ease om 2005 on-
wa ds (Fig. 3B, Suppl. ma e ial 1: ig. S4). The coun ies wi h he la ges numbe
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João Ra o e al.: E ec i eness o legisla i e ools o s op biological in asions
o eco ds all belong o he EU, namely Po ugal, Spain, The Ne he lands, and
Belgium (Fig. 4B). The emaining coun ies only ha e occasional eco ds by squa e
kilome e (Fig. 4B).
Discussion
F om ou esul s, we can conclude ha , despi e he legisla ion leading o a e-
duc ion in T. sc ip a impo s, he eco ds o his species did no dec ease in he
wild. On he o he hand, o he eshwa e u les (FT) impo s inc eased wi h he
legisla ion implemen a ion, and hese impo s could a leas pa ially explain he
inc ease in eco ds o o he FTs in he wild.
Impo s o T. sc ip a ceased en i ely wi h he implemen ing Regula ion 1141/2016,
which may lead o a educ ion o new in oduc ions o his species. Addi ionally,
p opagule p essu e is also impo an a he pos -es ablishmen s ages o in asion
(Colau i and MacIsaac 2004), as i p omo es he a i al o new p opagules om he
ou side o he es ablished popula ions. Al hough in e na ional ade was s opped,
he same migh no ha e happened wi h he in-coun y and illegal ade. This was
also ound o o he axonomic g oups, o ins ance, in he Aus alian o namen al
ish indus y, se e al black-lis ed species con inue o be aded, pa icula ly h ough
e-comme ce (Milling on e al. 2022). This migh be educed by applying s ong
con ol o he in e nal ade o pe species, and no ocusing only on in e na ional
ade (Milling on e al. 2022). I is ele an o no e he e ha he mean impo s o T.
sc ip a in non-EU coun ies a e e y low compa ed o EU coun ies, which migh
be ela ed o he low GPD o non-EU coun ies (E ans e al. 2018).
E en while T. sc ip a impo s dec eased be ween 1998 and 2000 and eached a
ela i ely low le el a e ha yea , eco ds did no ollow he same end. A e 2003,
T. sc ip a eco ds we e con inuously inc easing, and in 2018, he e was a la ge inc ease
in he numbe o eco ds ha was main ained high un il 2022. This aligns wi h he
gene al end obse ed in he eco ds o all u le species in Eu ope, whe e a mean o
40% ( anging om 17% o 64%) o annual eco ds a e a ibu ed o T. sc ip a. In ou
s a is ical analysis we included, as a andom ac o , he eco ds o all u le species in
Eu ope o accoun o he inc easing use o ci izen science pla o ms o e he yea s,
and so ou esul s al eady conside ha e ec . Despi e no being s a is ically signi i-
can , he a iable T. sc ip a impo s ollows he opposi e end o he T. sc ip a eco ds.
This is an indica ion ha he impo s’ educ ion did no a ec he eco ds in he wild,
and he e o e a blacklis alone has no s opped he in asion o T. sc ip a. The same
happened wi h T. sc ip a eco ds a e he na ional legisla ion implemen a ion in Spain
(Maceda-Veiga e al. 2019). Al hough legisla ion implemen a ion inc eased he ol-
un a y su ende ing o animals o he compe en au ho i ies and he con isca ion o
p ohibi ed species, he numbe o wild/ e al indi iduals emained unchanged (Mace-
da-Veiga e al. 2019). The EU egula ion 1143/2014 also includes o he measu es o
con ol and e adica e in asi e species, howe e , since he numbe o T. sc ip a is in-
c easing, he EU egula ion, as i is, migh be ine ec i e o s op he T. sc ip a in asion.
The e a e se e al explana ions o he inc ease in T. sc ip a eco ds, ins ead o i s
educ ion. Fi s ly, he measu es p edic ed in he 1143/2014 egula ion a e ei he
no being applied by he EU membe s a es o hese measu es, despi e being ap-
plied, a e no su icien o s op T. sc ip a in asion. Addi ionally, due o he ac ha
T achemys sc ip a is a long-li ed species, he impac o some con ol measu es (like
egg emo al) migh no be e iden ye . Secondly, T. sc ip a was al eady p esen in
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Supplemen a y ma e ial 1
Supplemen a y igu es S1–S4 and ables S1, S2
Au ho s: João Ra o, Ped o B andão, Ma alda Gama, Filipe Banha, Ped o Anas ácio
Da a ype: pd
Copy igh no ice: This da ase is made a ailable unde he Open Da abase License (h p://openda a-
commons.o g/licenses/odbl/1.0/). The Open Da abase License (ODbL) is a license ag eemen
in ended o allow use s o eely sha e, modi y, and use his Da ase while main aining his same
eedom o o he s, p o ided ha he o iginal sou ce and au ho (s) a e c edi ed.
Link: h ps://doi.o g/10.3897/neobio a.102.143330.suppl1
Supplemen a y ma e ial 2
Tukey es esul s
Au ho s: João Ra o, Ped o B andão, Ma alda Gama, Filipe Banha, Ped o Anas ácio
Da a ype: xlsx
Copy igh no ice: This da ase is made a ailable unde he Open Da abase License (h p://openda a-
commons.o g/licenses/odbl/1.0/). The Open Da abase License (ODbL) is a license ag eemen
in ended o allow use s o eely sha e, modi y, and use his Da ase while main aining his same
eedom o o he s, p o ided ha he o iginal sou ce and au ho (s) a e c edi ed.
Link: h ps://doi.o g/10.3897/neobio a.102.143330.suppl2
Supplemen a y ma e ial 3
Supplemen a y da a no e
Au ho s: João Ra o, Ped o B andão, Ma alda Gama, Filipe Banha, Ped o Anas ácio
Da a ype: pd
Copy igh no ice: This da ase is made a ailable unde he Open Da abase License (h p://openda a-
commons.o g/licenses/odbl/1.0/). The Open Da abase License (ODbL) is a license ag eemen
in ended o allow use s o eely sha e, modi y, and use his Da ase while main aining his same
eedom o o he s, p o ided ha he o iginal sou ce and au ho (s) a e c edi ed.
Link: h ps://doi.o g/10.3897/neobio a.102.143330.suppl3
