Habitat use of the micro-endemic day gecko Phelsuma antanosy in Sainte Luce, Madagascar, and the case for translocation

Abstract

The Critically Endangered day gecko Phelsuma antanosy is micro-endemic to 2 humid forest sites in southeastern Madagascar. At one of these, Sainte Luce, it inhabits 4 forest fragments, 2 of which are set to be cleared for mining. Translocation of individuals from within the mining path to protected forest fragments has been proposed to mitigate the impact of habitat loss and the resulting reduction in population size. However, lack of knowledge of its habitat requirements and population structure inhibits efforts to evaluate the likely ecological consequences of translocation. We sampled 92 P. antanosy individuals across each of the known subpopulations in Sainte Luce and assessed the habitat conditions in which they occur, alongside levels of morphological variation. Using 5 morphological trait measures, we found no evidence of subpopulation differentiation. Almost all (>87%) P. antanosy individuals were found on Pandanus longistylus plants and occupancy levels were higher in areas with moderate (30-60%) canopy cover and no other Phelsuma spp. present, suggesting that translocated individuals should be located into these conditions and within a short (<5 m) distance of P. longistylus plants. We propose that siting individuals in patches meeting these criteria may help to maximise translocation efficacy. We discuss our results in the context of the lack of ecological and genetic information on this species, the general need for long-term monitoring of threatened species and the utility of translocation projects to inform and benefit conservation science.