Reunion Island is a 2500 km² French over sea territory located on Indian Ocean. It lays 700 km east of Madagascar and about 150 km west of Mauritius Island. Endemism is very high but suffered high losses since human arrival (17th century); regarding terrestrial reptiles, 4 species have proved to be extinct and the 3 remaining ones are highly threatened, including project target species, Reunion day gecko Phelsuma borbonica. This endemic gecko is an Endangered species EN: preliminary studies show a highly fragmented distribution despite a noticeable capacity to adapt to well distinct habitats, from sea level to altitudes above 2300 m high. Continuous habitat degradation but also habitat loss and predation are the main threats; introduced invasive plants close habitats and microhabitats, but also limit food resources; agriculture, urbanization and accidental fires may totally destroy habitats; introduced animals such as rats and cats can dramatically predate on individuals.

Also, the Reunion day gecko is a highly polymorphic species that has been poorly studied. Two subspecies are endemic to Reunion P. borbonica borbonica and P. borbonica mater and a 3rd, the P. borbonica agalegae, is endemic to Agalegae Islands in Mauritius. All subspecies descriptions were only based on morphological characters from very few individuals and taxonomic assessment remain doubtful. Phylogeography is poorly understood. On La Réunion, for the last ten years, highly divergent populations were discovered in very specific habitats including high altitude heather shrubland and highly threatened habitats. These taxa may not be related to existent ones and should be denominated Phelsuma borbonica sl. The overall objectives of the project are:
1. to get basic ecological data and samples of P. borbonica sl. (biometric, meristic and DNA);
2. to assess taxonomic identity of all these populations based on phenotypic and genetic evidence. Such work may result in the description of new taxa; it will help assessing conservation priorities;
3. to lead a communication and advocacy campaign on P. borbonica: new taxonomic key, ecology and threats, conservation management...

Presence of highly diversified populations of P. borbonica with presumably new taxa will highlight the importance of conservation of both habitats and gecko.