conservation in Mauritius: Reptile conservation in Mauritius: Restoring island biodiversity IslandRestoring Biodiversity island biodiversity &

• TheIslandsIsolated isolation, and reptile uniqueness and extinction plants, and such dependency as those thatof island • Mauritius:speciesnaturally upon colonise An islandone anotherislands, of unique makesoften co-evolve them vulnerable and adapt to • Theextinctionto utilise need all for available reptile conservation resources and translocation • SinceThisRe-building drives the 17 speciationendemicth Century reptile and75% theof communities all formation of unique • haveTheecosystems future been islandfor Mauritian endemics reptiles • Islands therefore maintain some of the richest biodiversity in the World

Nik Cole

Island Biodiversity & Extinction Mauritian reptiles

• Although the Mascarenes have lost more • OfAlthoughTherePreventing the have28 reptilethe furtherbeen loss extinctions more ofloss species reptile of reptile over is extinctions relatively species,the past few,in400 the years,the than anywhere else, Mauritius still maintains one of allcurrentMascarenesparticularly but one loss have island ofthan reptile occurred anywhere endemics, diversity on else islandsis istherefore occurring of atgreat an the richest reptile diversities in the World alarmingimportance rate in and maintaining considered global as a biodiversity GLOBAL CRISIS! Fiji Africa Extinct MauritianNew Zealand Giant Tortoise Cylindraspis inepta Canary Islands Seychelles12 Extinct Giant Mauritian CapeLeiolopisma Verde Islands mauritiana 10

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4 Caribbean Mascarenes 2 ?

Reptile extinction events 0 1600- 1700- 1800- 1900- 2000- 1699 1799 1899 1999 2099

Mauritian reptiles the formation of an ecosystem with:

• TheBeforeThis reptiles allowed the arrival and an adaptivebirds of man, therefore radiation some 400filled of years all the ago, roles there in • REPTILIAN PREYPREDATORSSEEDHERBIVORES forDISPERSERS other oflarger birds, reptiles &reptiles POLLINATORS and and birds invertebrates thewere ecosystem no mammals usually in Mauritius occupied accept by mammals for bats maintainingallowing habitat the natural regeneration habitat through browsing & grazing

Giant tortoises Snakes

1 A MauritianUnfortunately ecosystem that Extensive destruction of was dependent upon reptiles natural habitat • A system rarely seen anywhere else

The arrival of people in Mauritius has led to the near destruction of much of this unique ecosystem

IntroductionExtensive destruction of numerous of These disturbances caused non-nativenatural habitat species • The loss of more than 60% of the unique reptile species from the mainland Reptilian predators and competitors Reptilian predators and competitors

Mammalian predators Mammalian predators

The offshore islands TheRound offshore Island islands

• DisturbanceManyBut as reptile island tospecies use the increased, offshore lost from islands disturbance the mainland occurred increased: continued at a • RemoteBut as island and relatively use increased, difficult disturbance to access increased: slowerto– surviveRemaining rate on reptile the islands populations declined – Remaining reptile populations declined rats and other introduced predators responsible for – Many island populations disappeared = further extinction – Many island populations disappeared = further extinction reptile extinction never reached the island – But some of the more remote and least disturbed island – But some of the more remote and least disturbed island populations continued to persist populations continued to persist – For example: – For example:

2 Round Island The need for conservation • 30 years ago it was recognised that: • andTheBecame theisland last the also locationlast supports location where onhealthy the Earth burrowing populations to find: boa, of other Bolyeriaendemic multocarinataand native reptilewas species seen in 1975 KeeledGunthers scaled , boa, Phelsuma Casarea dussumieriguentheri

Ornate day gecko, Phelsuma ornata Bojer’s skink, Gongylomorphus bojerii

HOME TO THE LAST SEMI-INTACT REPTILE COMMUNITY TheTo safeguardRoundTheIntroduced future Island againstsurvival goatsreptile further ofand community this rabbits disturbance reptile WITHIN THE MASCARENES andwasthatdominated ultimately unique were destroying andecosystem reptile extremely extinction the was reptiles’ important at great populations habitat risk Durrell’sTelfairs nightskink,Bouton’s gecko, skink, Nactus telfairii durrelli shouldfor thebe re-establishedbiodiversityhad to be removedof backthe region to other islands Cryptoblepharus boutonii Bullock & North 1975

The need for conservation The need for conservation • But…Most of 30 the years populations ago little werewas knowntoo vulnerable about: • ThereThisIslandTheseLittleOver researchwasthe hasrestorationactions past known been threehashave extensive about anddemonstrated decadesbeen reptile the the researchother theresearchbackbone Forestrytheislands into need is to reptilenow Service, forisland there- ecology,establishingrestorationfoundationDWCT,– was there conservation, MWF tosuitable island whatand captiv NPCS habitat?reptilewase suggested husbandry, thecommunities driving genetics, 30 force: years , ago: health and disease, and past and present distributions – RestoreRoundwereHabitat other Islandrestorationmissing vulnerable reptile ecological populations reptiles processes present? have and increased island biodiversity TRANSLOCATION – EnhancedramaticallyEradicationwere exotic the ofpredators/competitorslong-term mammalian survival predators of endangered present? and herbivores reptiles – Some islands now suitable for reptile re-establishment

TheThere reptiles’ were not pastecologicaltaxonomydistribution sufficient co-existence requirements numbers to remove and re-establish elsewhere

The needTranslocation for conservation Translocation • TheIsland movement restoration of anda species reptile from research one location is now the with • Re-introductionThe two most importantand re-stocking initial stepsare common are: freefoundation release to in what another was –suggested 3 types: 30 years ago: and1) Determinepowerful and conservation remove the causes tools of initial species loss – Introduction: species release outside its natural range 2) Determine the ecological requirements of the species – Re-introduction:TRANSLOCATION species release within its past former range • However, some question the validity of this tool – Re-stocking: species release within an existing population • forIt reptiles,is also essential because that success post-translocation and impact has beenmonitoring poorly documented! is conducted to assess – success of establishing a new population • The– theInternational impact to the resident Union species for the Conservation of Nature– the need and for Natural further action Resources – restocking(IUCN) have set guidelines for species translocation

3 Re-building reptile communities Re-building reptile communities • In 2006 (Darwin Initiative funding) we initiated the • Telfair’s skink first reptile translocations in the Indian Ocean – Restricted to Round Island, but once widespread – Dec 06 to Feb 07 – The mainland and other island populations destroyed by • It was essential that we chose species based on – rats250260 skinks to IleGunners aux Aigrettes Quoin – needsuitability for conservation of potential islands: action “vulnerability to extinction” – Re-establishing this skink back to other islands – current• suitable stability habitat within the donor populations represents an important step in restoring island ecosystems – knowledge• food availability of their ecology and role in the ecosystem • lack of introduced predators – As we are reinstating a lost predator, seed disperser, • stable populations of resident endemic species pollinator and potential prey item

• Four reptile species and four islands were selected:

Re-building reptile communities Re-building reptile communities • Ilot Vacoas Bojer’s Skink, Gongylomorphus bojerii sp. – Restricted to Ilot Vacoas, only 1ha! • Night geckos,geckos Nactus spp. – 400 skinks inhabit the island – AJan sub-species 07 to the Bojer’s restricted to the N islands – 20 skinks to Ile aux Fouquets • Nactus– These small coindemirensis geckos were once widespread and possibly the most abundant vertebrates in pristine Mauritius

– Underwent catastrophic reduction in range following the introduction of the house gecko, Hemidactylus frenatus – Once widespread in the SE – IncludingThis is the the first neighbouring of several annual islands translocations until the 1930s from & 70sIlot – TheseVacoas island to Ile populationsaux Fouquets predated • Nactus durrelli by shrews and elsewhere by wolf snakes

Re-building reptile communities Re-building reptile communities • Nactus coindemirensisonly survive on restrictedislands where to: the house • Nactus durrelli restricted to Round Island

gecko• Ilot has Vacoas not reached Pigeon Rock • Both night geckos are now segregated from one Flat Island Round • Gunners Quoin another Island Gunners Quoin • A small area of rock on Flat Island • Translocation is limited, because of house gecko • Pigeon Rock distribution • Beneficial to translocate both night geckos to the same island • But could we successfully translocate both night geckos to the same island at the same time? Ilot Vacoas

4 Re-building reptile communities Re-building reptile communities • OctIlot Chat06, we perfect tested site this theory • MONITORINGPrior to release progress each reptile and impactwas given is a its major own – Small 0.03ha = easy to control and monitor componentidentity to aid of inany post translocation translocation monitoring

Ilot Chat

• 30 Nactus coindemirensis – No introduced competitors or predators – Telfair’s skinks were PIT tagged • 30 Nactus durrelli – All others too small for tagging given photographic IDs – Pattern of scaring, missing toes/claws, tail breaks recorded

Re-building reptile communities Re-building reptile communities • DetermineHealth and disease status screened prior to and at • ToCreated assess transects the IMPACT on the islands to: regular– Dispersal intervals and distribution after translocation Surveyed– SurveySample nativeBojer’s terrestrialthe resident and skinks invertebratenon-native and terrestrial night vertebrate populations geckos species to populations determine using prior to the – Survival and recruitment usingimpact• Pitfall Distance of trapping removing Sampling individuals from the small – Obtain blood samples from the larger Telfair’s skinks and at regular intervals after translocation populations• Winkler litter on extraction Ilot Vacoas # # # # • Compare## # blood values between populations in each season # # ### # ###### #### # ## ### ## – Red# blood cell volume – dehydration / anaemia / injury # # # # ### # # # # ## # ## ######## # # ######## # ######### ############### – Protein content# – starvation / disease####### # ##### # # #### # # # # # # # – Smears – parasitology### # ## # #

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Telfair’s skinks on Gunners Quoin – Compare body condition scores between populations each season • Ratio of length to weight • Number of scars, missing toes and tail breaks per individual • Number of ectoparasitic mites and presence of worms in faeces

Re-building reptile communities The future for Mauritian reptiles • To determine the adaptability and ecological role of • Is there a brighter future for Mauritian reptiles? the translocated reptiles on the recipient islands

• Yes, as long as we can continue to protect and restore island habitats and prevent further alien seasonal comparisons with donor populations’ introduction utilisation of habitat and diet

5 The future for Mauritian reptiles • The actionsimpact sowe far have is positive taken in with the potentiallast year benefitsto • These are the foundations to restoring island reptile translocateto island restoration reptiles is and already island proving ecosystems successful! communities from which we can build upon: • OnNativeNo detectableIle auxseed Aigrettes, dispersal –ve impacts Telfair’sthe is occurring upon skinks potential introducedhaveareresident heavily reducedreduced endemic predatingwolf the Agamid snake introduced prey the populationshrewencounterintroducedor competitors population ratesAfrican remains to to land very snail low in25%1/10 theth of ofpresence pre-skink pre-skink levelsof rates Telfair’s

Reptile conservation has been a team effort involving many people Only with collaboration can we continue • AddingAnd possibly the next using ecological some as building analogues blocks for toextinct to restore these unique communities • AsWork well toward as restoring restoring other threatened vulnerable mainland island populations species •• Telfair’sAllNightBojer’sislands Re-establishingspecies populations geckos: skinks: skinks:with in Rodrigues established co-existing breedingremain mating species on fit Ileon andpreyon andaux Ile other Aigrettes healthy breedingsourcesaux islandsFouquets and onGunners Ilot ChatQuoin Thank you!

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