|Scientific Name:||Rhacodactylus chahoua|
|Species Authority:||(Bavay, 1869)|
Platydactylus chahoua Bavay, 1869
Recent genetic data shows populations in northern Grande Terre and on the Iles Belep are highly distinct.
|Red List Category & Criteria:||Vulnerable B1ab(i,ii,iii)+2ab(i,ii,iii) ver 3.1|
|Assessor/s:||Whitaker, A.H. & Sadlier, R.A.|
|Reviewer/s:||Tognelli, M. & Cox, N.A.|
This species is listed as Vulnerable because it has a restricted and severely fragmented distribution and there is continuing decline in its extent of occurrence, area of occupancy and extent and quality of its habitat due to a variety of threats.
|Range Description:||This species is endemic to New Caledonia. It occurs in Grande Terre, Iles Belep (Ile Art only) and Ile des Pins. Very few widely scattered localities are known and at many of these the continued occurrence of this species is uncertain. It occurs at elevations of up to 500 m. The extent of occurrence is approximately 16,600 km², and the area of occupancy is estimated to be < 1,000 km².
[Extent of occurrence was based on a crude measure of overall length times width of the most distant known locations (a rough measure of the line around the points), except for very widespread species where the published areas of the islands were taken. Area of occupancy is a contraction of that rough estimate for extent of occurrence based on where habitat remains.]
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are no quantitative data on population size or trends. It is presumed to have suffered a substantial past reduction in population size and extent through habitat loss, mainly associated with logging and the clearance of lowland forests for agriculture. This species remains relatively common at a few sites but at others there are clear indications that the populations are declining, e.g. on Dôme de Tiébaghi closed forest habitat occupied by Rhacodactylus chahoua is being lost to expansion of the nickel mine and degraded by mining activities.|
|Habitat and Ecology:||This species inhabits gallery and closed forests. It is nocturnal and arboreal. It shelters by day in tree crevices and holes and forages at night in the canopy.|
|Major Threat(s):||The primary threat to this species is the continued loss or degradation of forest habitat. This is a particular risk near settlements and along river valleys where agricultural activities are intensifying, and on Ile des Pins where there is the additional effect of increased tourism. Mining is a much lesser risk to Rhacodactylus chahoua than other lizard species as only a very small proportion of its known occurrence (two locations: le Art and Dôme de Tiébaghi) is on the ultramafic surface where nickel occurs. Other threats to this species include habitat loss or degradation from wildfires (particularly Iles Belep) and the effects of introduced ungulates (deer and pigs). Predation by introduced mammals is a constant threat, especially rats as they are abundant in lowland forest habitats and capable of foraging in the canopy. It is expected that the introduced ant, Wasmannia auropunctata, will be a substantial threat as it is known to have a detrimental impact on lizard populations (Jourdan et al. 2000, 2001). Illegal collection and trafficking of Rhacodactylus chahoua is a risk at accessible locations.|
|Conservation Actions:||This species is protected in Province Nord under Code de l'environnement de la Province Nord (Délibération No. 306-2008/APN, 24 October 2008) and in Province Sud under Code de l'environnement de la Province Sud (Délibération No. 25-2009/APS, 20 March 2009). One location at which Rhacodactylus chahoua occurs (Rivière Nehoué) is administered as a recreation reserve but it receives high human use and it is not known to occur in any other protected areas. No species-specific conservation management is currently being undertaken.|
Bauer, A.M. 1985. Notes on the taxonomy, morphology and behaviour of Rhacodactylus chahoua (Bavay) (Reptilia: Gekkonidae). Bonner Zoologische Beiträge 36: 81-94.
Bauer, A.M. and Sadlier, R.A. 2000. The Herpetofauna of New Caledonia. Society for the Study of Amphibians and Reptiles, Ithaca, New York.
IUCN. 2011. IUCN Red List of Threatened Species (ver. 2011.1). Available at: http://www.iucnredlist.org. (Accessed: 16 June 2011).
Jourdan, H., Sadlier, R.A. and Bauer, A.M. 2000. Premières observations sur les conséquences de l’invasion de Wasmannia auropunctata 1863 (Roger) sur les prédateurs supérieurs dans les écosystèmes Néo-calédoniens. Actes des collectes insectes sociaux 13: 121-126.
Jourdan, H., Sadlier, R.A. and Bauer, A.M. 2001. Little Fire Ant Invasion (Wasmannia auropunctata) as a Threat to New Caledonian Lizards: Evidences from a Sclerophyll Forest (Hymenoptera: Formicidae). Sociobiology 38(3A): 283-301.
Seipp, R., and Henkel, F.W. 2000. Rhacodactylus: biology, natural history and husbandry. Edition Chimaira, Frankfurt.
|Citation:||Whitaker, A.H. & Sadlier, R.A. 2011. Rhacodactylus chahoua. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 05 December 2013.|
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