Contents Mauritian reptiles Restoring island biodiversity: Mauritian reptiles Restoration and research the reintroduction of endemic Mauritian reptiles Skinks and geckos The Darwin Initiative project Dr Nicholas Cole University of Bristol Project protocol and timetable Dr Carl Jones Durrell Wildlife Conservation Trust Mauritian Wildlife Foundation Mauritian reptiles Mauritian reptiles Once one of the richest reptile diversities in the World This adaptive radiation caused the formation of a unique ecosystem In the absence of terrestrial mammals the reptiles evolved to occupy all available niches dependent upon reptiles Allowed adaptive radiation of: Tortoises Nocturnal and diurnal geckos Skinks Reptiles occupied all main functional Snakes groups: Mauritian reptiles Mauritian reptiles Predators: Prey: 1 Mauritian reptiles Mauritian reptiles Grazers and browsers: Seed dispersers: Mauritian reptiles Mauritian reptiles Pollinators: Human related disturbances over the past 400 years: Extensive habitat destruction Introduction of non-native predators and competitors More than 60% of reptile species lost from the main island through extinction or extirpation The majority of the extant species are now confined to offshore islands Mauritian reptiles Restoration and research Remaining island populations: Round Island Most intact reptile fauna of the Mascarenes Restricted and/or fragmented distributions Never invaded by predatory mammals or reptiles The loss of ecological links and food webs Habitat destruction caused by rabbits and goats - loss of stability deleterious affect on reptiles Vulnerable to further disturbances Vulnerable to further disturbances 30 years ago: Purposeful and accidental introductions Restore island communities Anthropogenic and stochastic events Translocate reptiles Maintain Round Island for comparative studies 2 Restoration and research Restoration and research 30 years ago: Extensive research on Mauritian reptiles over the 30yrs Recipient islands unsuitable and little known > 40 peer-reviewed publications Donor populations too vulnerable ecology Little known about the ecological requirements, conservation distribution and taxonomy of the species taxonomy The need for restoration & translocation repeated genetics e.g. Hartley, Bloxam, Tonge, Bullock, Arnold, Cheke, Merton, Bell disease and health past and present distributions Forestry Service, DWCT, MWF and NPCS the driving force: driving force: Many unpublished reports Habitat restoration Numerous academic studies Ph.D., M.Sc., B.Sc.. Eradication of mammalian predators and herbivores Restoration and research Skinks and geckos The next step in the restoration process: Essential to start with the ecological building blocks (most widespread and abundant) The skinks Re-establishing reptile communities Bojer’s skink, Gongylomorphus bojerii Telfair’s skink, Leiolopisma telfairii The geckos Durrell’s night gecko, Nactus durrelli Lesser night gecko, Nactus coindemirensis SI Bojer’s skink RI PHR Most widely Skinks and geckos FI GI distributed skink Re-establishing populations of Bojer’s GQ skink, Gongylomorphus bojerii Historical accounts and Mauritius fossil records for 3 islands and throughout IAF the mainland IDLP Principle causes IV of decline: Wolf snakes IAA Shrews Rats 3 Skinks and geckos Skinks and geckos Freeman (2003) demonstrated Ilot Vacoas skink population Bojer’s skinks in high densities Show a significant genetic separation from other Bojer’s skinks in high densities populations Risks of inbreeding depression prevented by low Must treat as a separate conservation management level migration, thus maintaining genetic variation unit However: At great risk from further disturbances no migration for Ilot Vacoas and a great risk of Their future survival is dependent upon translocation inbreeding depression With up to 490 skinks translocations will have to be small and repetitive Skinks and geckos Skinks and geckos Ile aux Fouquets Re-establishing populations of Telfair’s Most ideal site for first translocation Skinks present until at least 1972 skink, Leiolopisma telfairii Shrews no longer present Telfair’s skink RI Restricted to FI Round Island Skinks and geckos GQ Historical Highly abundant - 10-15,000 accounts and Robust generalist along the three fossil records Mauritius for 2 islands important niche parameters (Food, and Space, Time) throughout the mainland Adaptable to change – an ideal candidate An important component of the pristine IDLP Principle cause Mauritian ecosystem: of decline: Evidence for Rats IAA other islands Predator / Prey / Seed Disperser / Pollinator 4 Skinks and geckos Skinks and geckos Telfair’s repeatedly identified for translocation to: Telfair’s repeatedly identified for translocation to: Ile aux Aigrettes Ile aux Aigrettes Gunner’s Quoin Ideal habitat (possibly more suitable than Round Is) Flat Island Cats and rats eradicated by 1991 Ile Marianne Ile aux Fouquets An abundant food source: invertebrates, fruits and reptiles Ile de la Passe Potential impact upon exotics: Predation of African land snails and wolf snakes Competitive exclusion of the shrew (may allow further re-introductions?) Ecotourism & education - increasing awareness of biodiversity issues Skinks and geckos Skinks and geckos Telfair’s repeatedly identified for translocation to: Some have highlighted concerns for the lesser night gecko, Nactus coindemirensis Ile aux Aigrettes Gunner’s Quoin Suitable diversity of habitat types Rats eradicated in 1995 An abundant food source: invertebrates, fruits and reptiles Replacement of a lost predator Potential prey item for future reintroductions Disperser of Pandanus seeds and pollinator of Latania Co-existed with Telfair’s skink, then rats from the 1860s for 130 yrs Demonstrate anti-predatory behaviours Mostly active in different time niche Significant population growth post rat eradication Skinks and geckos Skinks and geckos Encounter rates Nactus coindemirensis Telfair’s repeatedly identified for translocation to: Ile aux Aigrettes Cats, mice and rats eradicated 1998 Gunner’s Quoin 1982 1993 1996 2003/4 Gunner’s Quoin Central Flacourtia thicket - - 0* 4* Flat Island Need sufficient time for recovery of Eastern cliffs - - 0* 24.5 Ile Marianne orange tail skinks Latania/Pandanus slopes - - 0* 36.0 Ile aux Fouquets Northern cliffs - - 0* 13.0 Management plan for the vulnerable Ile de la Passe population of lesser night Northern peninsula - - 1* 45.5 geckos Pandanus slopes - - 2.5 47.5 Southern peninsula 0.8 0.0 2.5 38.5 Summit - - 0* 35.5 Bullock et al 1985 Valley - - 0* 18.0 Bullock 1986 Western cliffs - - 0* 35.0 Arnold & Jones 1994 Ilot Vacoas - - - 49.0 Dulloo et al 1996 Pigeon House Rock - - - 58.0 Cole 2005 5 Skinks and geckos Skinks and geckos Telfair’s repeatedly identified for translocation to: Ile aux Aigrettes and Gunners Quoin Ile aux Aigrettes Gunner’s Quoin most suitable sites for translocations Flat Island Ile Marianne Habitat currently unsuitable Ile aux Fouquets Ile de la Passe Initially more valuable for establishing smaller reptile species Skinks and geckos Skinks and geckos Re-establishing populations of night The night geckos: geckos: Lesser night gecko, Nactus coindemirensis Three Nactus species Skinks and geckos Skinks and geckos The night geckos: The night geckos: Durrell’s night gecko, Nactus durrelli Serpent Island night gecko, Nactus serpensinsula 6 Nactus serpensinsula Night geckos Nactus durrelli Skinks and geckos Nactus coindemirensis Relict populations The most abundant reptiles in pristine Mauritius Habitat Would have been an important prey item Mauritius destruction & for other reptiles and birds mammalian predators unlikely to be Catastrophic reduction in range the sole cause of declines Now extremely fragmented distribution Nactus coindemirensis Skinks and geckos Skinks and geckos Declines attributed to the introduced common house Comparisons of habitat, diet and temporal activity: gecko, Hemidactylus frenatus Ecologically very similar to all night geckos Competition for: Refugia Microhabitats based on thermal properties Invertebrate prey Enclosure experiments excluded the night geckos from refugia attacked and predated the night geckos Responsible for the exclusion of night geckos Nactus serpensinsula Night geckos Nactus durrelli only exist in House gecko absence of the Skinks and geckos Nactus coindemirensis house gecko Flat Island Beneficial to translocate night gecko unique situation species to the same island separated by species to the same island differences in morphology and microhabitat Lesser night gecko would have existed Ile Marianne with the ancestor of the larger two night geckos Ilot Chat At risk from further invasion Nactus coindemirensis The ancestor was most similar to Few islands left for translocation Durrell’s night gecko 7 Skinks and geckos Skinks and geckos Comparisons of habitat, diet and temporal activity Enclosure experiments demonstrated: Partitioning of these niches past competition The lesser and Durrell’s night gecko did not compete between the species past co-existence Had no impact upon one another Experiment to short to demonstrate that competition Serpent Island and Durrell’s night geckos may have been acting over a longer period Very little partitioning Differences - 10,000 yrs of isolation on different islands Need to investigate the long term co-existence Lesser night gecko