Reptile conservation in Mauritius Pristine Mauritius Nik Cole 671 species of plant 46% endemic to Mauritius The forests supported 22 types of land bird, 12 endemic to Mauritius, such as the dodo The Mauritius forests had also 23 supported different types unique of reptile, reptiles22 endemic Except for bats, Mauritius never used to have mammals With no terrestrial mammals, Mauritius was a reptile and bird dominated island REPTILIAN PREY PREDATORS SEED HERBIVORES for DISPERSERS other of larger birds, reptiles & POLLINATORS and birds invertebrates maintaining allowing habitat the natural regeneration habitat through browsing & grazing 1
Many animals from other countries 1872 1773 Today 183 193 <2% Reptiles Whilst the forests supported the reptiles and birds 1638 people settled in Mauritius Reptiles helped to support the forests and the forests were rapidly destroyed Birds Mammals Some The loss that were of were forests completely lost and from lost the the introduction from mainland Mauritius managed of animals - EXTINCT to from survive outside on Mauritius the surrounding caused the islands, loss of where many the reptiles disturbance was not as severe Round Island One of the few places not invaded by rats Round Island Other Islands of importance The Became island the also last supports location on healthy Earth populations to find: of other endemic and native reptile species Keeled Gunthers scaled gecko, boa, Phelsuma Casarea dussumieri guentheri Ornate day gecko, Phelsuma ornata Bojer s skink, Gongylomorphus bojerii HOME TO A REPTILE COMMUNITY THAT USED TO OCCUR THROUGHOUT MAURITIUS Durrell s Telfairs night skink, gecko, Leiolopisma Nactus telfairii durrelli Bouton s skink, Cryptoblepharus boutonii Lesser night gecko Ilot Vacoas Bojer s skink 2
Other Islands of importance The need for conservation It was recognised that: Orange-tail skink Their future survival was at great risk To safeguard against extinction, the reptiles should be re-established back to other islands The need for conservation There These Island This Over Work research the was has restoration actions past started been three has have strong extensive and to led decades been restore reptile support new the Round the research discoveries backbone for Forestry re-establishing Island into has to reptile of Service, and species been ecology, island conservation species Durrell, other foundation islands reptile conservation, MWF populations communities around and for: the captive NPCS offshore Mauritius husbandry, on the other driving islands genetics, islands force: taxonomy, health and disease, and past and present distributions Restore Habitat restoration missing ecological processes and island biodiversity Enhance Eradication the of long-term TRANSLOCATION mammalian survival predators of endangered and herbivores reptiles Translocation The movement of a species from one location with free release in another 3 types: Introduction: species release outside its natural range Re-introduction: species release within its past former range Re-stocking: species release within an existing population Translocation Re-introduction and re-stocking are common and powerful conservation tools However, where do we start? How do we decide what goes where and when? First we need to decide upon what we want to achieve Prevent further extinction Rebuild reptile communities Refill the gaps within island ecosystems to restore missing ecological processes 3
We need to know: What was present prior to disturbance What caused the original loss of the species We need to know: What is currently present/missing from an island that could prevent re-establishment Presence of invasive and natural predators/competitors Know your species ecology determines the pattern of reintroduction cannot translocate a predator without prey! How vulnerable is: the donor population we want to translocate from (removal of individuals does not cause extinction) the recipient populations at the release location (adding a predator/competitor does not cause extinction) How secure are the release sites in terms of: The status of the location (nature reserve or golf course) Proposed plans for development (tourism plantation recreation) Need to adapt to changing levels of threat to species survival may require action that supersedes some of the previous considerations however, such actions should never threaten the survival of another endemic species Re-building Mauritian reptile communities In 2006, we initiated the first lizard translocations To date we have translocated five species to four islands 4
Planned translocations Translocate Telfair s skinks (Leiolopisma telfairii) from Round Island to Ile aux Aigrettes and Gunners Quoin 10 skinks moved from Dec 06 to Feb 07 Planned translocations Translocate the southeastern variant of Bojer s skink (Gongylomorphus bojerii sp.) from Ilot Vacoas to Ile aux Fouquets January 07 conducted the first annual translocation of 20 skinks from the 3-400 skink population January 08 conducted the second translocation of 20 skinks Re-Stocking Planned translocations Test the suitability of translocating two vulnerable night gecko species to the same island Durrell s night gecko (Nactus durrelli) from Round Island to Ilot Chat Lesser night gecko (Nactus coindemirensis) from Ilot Vacoas to Ilot Chat Unplanned translocations Orange-tail skink, Gongylomorphus fontenayi sp. Only known from Flat Island (199), very few seen Rats, cats and mice eradicated in 1998 By 2003 the population estimated at least 800 Current population at least 10,000 Ilot Chat Both translocations were completed in October 06 No immediate plans to work on the species Unplanned translocations Orange-tail skink, Gongylomorphus fontenayi sp. 2007 Prepared road sites opened for release through on the neighbouring population island closed nature Many reserve unconfirmed Gunner s plans Quointo enhance tourism Similar island developments = musk shrew and wolf snake = extinction of Gongylomorphus We needed to take action, whilst healthy population Northern Mauritius
MONITORING Prior to release progress each reptile and impact was given is a its major own component identity to aid of in any post translocation monitoring Telfair s skinks were PIT tagged Species too small for tagging given photographic IDs Pattern of scaring, missing toes/claws, tail breaks recorded Individual identity Determine Compare health and disease status of the reptiles over time and Dispersal between and islands distribution Survival, recruitment and population size (recapture rates) Investigate Created line IMPACT transects on on terrestrial the islands vertebrates to estimate and invertebrates Monitor the impact invertebrate over populations of removing time populations reptiles for and translocation diversity using Pitfall trapping Litter extraction Telfair s skinks on Gunners Quoin Habitat utilisation and niche shifts Restoring reptile populations The actions impact so we far have is positive taken in with the potential couple of benefits years are to island already restoration proving successful and island ecosystems On Native No detectable Ile aux seed Aigrettes, dispersal impacts Telfair s the is upon occurring endemic skinks introduced reduced have species reduced the wolf introduced Agamid snake land shrew snail not encounter populations seen for rates two to years 10% of pre-skink eradicated? rates Not all has gone quite to plan Ultimately we want rebuild island ecosystems to support endangered apex predators Telfair s Orange-tail Huge All Bojer s existing benefits, skinks: populations skinks: doubled restoration high >600 reproducing survival young remain world s on and drives Gunner s dispersal fit population on restoration and Gunner s Quoin on healthy IAA and Quoin GQ Rebuild the ecosystem step-by-step Each translocation put in place to support the next 6
Since we translocated night geckos in 2006: Invasive 4 introductions species to remain Ilot Chat a huge issue for island biodiversity Agamid lizard Musk Shrew Wolf snake Rat High level of monitoring on islands But detecting some species is not always straight forward particularly estimating populations Estimated 1 geckos on the island prior to the rat Caught and removed the first three before major impact The night gecko populations would have established Did not get the rat in time - night geckos lost How do we know what is there? How many dots? Quadrats 8 What happens when your dots move? 4 9 +9+8++4+ = 36 Average = 6/quadrat 7 quadrats to cover the page 7x6 = 40 Belt transects If too narrow can often lead to zero counts 10 6 9 6 1.2 12 Beneficial to widen the belt transect to get more counts, Assume 100% encounter 10 1 reduce effort 0.88 0.66 Wider the transect, less chance of detecting dots further 0.44 from the centre of the transect line 0.22 But, 100% chance of encountering dots along or very 0 0 1 2 3 4 close to the transect line Distance (m) ) Allows Remove you the to barrier estimate and the measure number the you perpendicular don t detect distance to each dot encountered Detection Number p ro b a bof ility animals 0 +10+6+0+9+6 = 36 Average = 6/belt transect 7 belt transects to cover the page 7x6 = 40 Numerous transects can calculate robust estimates DISTANCE SAMPLING free program and help online http://www.ruwpa.st-and.ac.uk/distance/ 7
Distance Sampling works very well Assuming that you can detect species along the transect line This is not always the case Went back to using quadrat method Enclosed to prevent emigration or immigration Enclosure Quadrats frequently used to measure diversity within and between habitats Often drives decisions on habitat conservation Healthy ecosystems considered to have high species diversity But need to consider the status of the species contributing to that diversity Shannon Index of species diversity - a measure of evenness Clearance Low diversity High diversity 0 > The only sure way of detecting the undetectable Obtain absolute densities Fieldwork Two habitats A diverse world: 1) Cocoa Krispies 2) Frosted/Corn flakes 3) Corn Pops 4) Honey Smacks ) Green Loops 6) Blue Loops 7) Yellow Loops 8) Purple Loops 9) Orange Loops 10) Red Loops 11) Blue M&Ms What is the population/density of cereal in each habitat? Is one habitat better for cereal diversity than another? 8