Taxonomy
Common name :
Le Gecko robuste des forêts Robust Forest GeckoRed List Status -
Near Threatened (NT) , assessed in 11/12/2017Protected species -
in Southern Province , in Northern ProvinceDescription
Description:
A medium to moderately large species of gecko growing to a body length of 83mm with a stout body and tail 100% that of the body length. It has moderately broad toes. The colour pattern on the top of the body typically has 4-5 pale blotches, dark-edged below, and the under surface is yellow.
Natural Distribution:
Recent studies on the New Caledonian endemic geckos show Bavayia robusta comprises two distinct genetic groups in southern New Caledonia:
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one with a distribution extending along the west coast from Dumbéa and Pointe Maa in the north to at least Mt Dore in the south (includes the type population on Mt Koghis), including adjacent offshore islands - recorded from coastal mangroves, coastal dry forest, and low and mid elevation humid forest habitats.
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one with a distribution that includes Forêt Nord in the far south of Grande Terre, and populations on the Ile des Pins and its satellite islands – recorded from coastal scrub and low humid forest on Ile des Pins, and from low elevation humid forest at Forêt Nord.
The status of populations of on the south-east coast formerly assigned to Bavayia cyclura are unknown but most likely are conspecific with Bavayia robusta.
Distribution within Province Sud: see above.
Habitat:
Humid forest on the Plaine des Lacs and low-mid elevation forest on chaine centrale; coastal mangroves; sclerophyll forest.
Threats:
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potentially high level of threat to populations in humid forest with high infestation levels of the introduced Little Red Fire Ant (Wasmannia auropunctata), resulting in a significant decline in abundance.
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potentially high level of threat to fragmented humid forest habitat on ultramafic soils through repeated firing of adjacent maquis habitat, leading to loss and degradation of the forest edge.
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moderate to high level of threat to coastal forest through loss, modification and fragmentation of forest habitat to local agriculture.
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localised but potentially high level of threat to significant populations in mangrove habitat through development.
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localised but potentially high level of threat from exotic pests such as rats and cats (predation of adults, young & eggs) in heavily affected forests, particularly on islands.
Conservation Status: Data Deficient
Both genetic groups are likely to be relatively widespread throughout their respective ranges – and the species is likely to be recorded from additional locations with further survey work. It occurs in coastal habitats (mangroves, dry forest, low-elevation humid forest) and in humid forest of the adjacent ranges. Because of its relatively broad distribution the species does not satisfy the criteria required to place it at a high level of threat, but most coastal habitat is highly fragmented, modified and infested with the invasive Little Red Fire Ant, and for this reason it is regarded as near threatened.
Bavayia robusta is listed as Near Threatened because the extent of occurrence is well below the threshold under criterion B and the populations are becoming increasingly fragmented due to habitat loss to development, wildfires, and the expanding mining industry (almost qualifies under criterion B1b(iii)). This species does not qualify for a threatened category yet because it is known from a relatively large number of locations and is abundant at some of them, and there are large areas of potential habitat that have not been surveyed.
Geographical area
Bavayia robusta is endemic to Province Sud, New Caledonia. It occurs from Port Boisé in the south to Mont Vulcain in the north. It occurs at elevations of up to 500 m. The extent of occurrence is estimated at 2,497 km2 and the area of occupancy at 92 km2.
Population
There are no quantitative data on population size or trends for Bavayia robusta but it remains abundant at some localities and has been able to colonize some modified environments (e.g. acacia woodlands). Presumed to have suffered a substantial reduction in population size and extent from past habitat loss and degradation, primarily through clearance for occupation and agriculture but also including wildfires and degradation by introduced ungulates (deer and pigs) and livestock. The rapid expansion of Nouméa and outlying suburbs is causing ongoing habitat loss across much of the species range.
Habitat
Bavayia robusta occurs in a wide range of wooded habitats including mangroves, coastal forest, sclerophyll forest and closed humid forest at low to mid-elevations. It is nocturnal and arboreal. It shelters by day in tree holes and crevices and beneath loose bark and forages at night to canopy height.
Threats
The main threats to Bavayia robusta are the loss and degradation of habitat. This loss will be particularly acute in mangroves and other coastal habitats which are under threat from urbanization, and for the isolated closed forest remnants in the Grand Sud that are at risk due to the rapidly expanding nickel mining industry. Other threats to this species include further loss or degradation of habitat from wildfires and the effects of introduced ant, Wasmannia auropunctata, and predation by introduced feral cats.
Conservation
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). Bavayia robusta is present in Parc zoologique et forestier Michel Corbasson, Vallée de la Thy, Rivière bleue and Ouen Toro. No conservation management is currently being undertaken.
Bibliography
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Wright, J.L., Bauer, A.M. and Sadlier, R.A. 2000. Two new gecko species allied to Bavayia sauvagii and Bavayia cyclura (Reptilia : Squamata : Diplodactylidae) from New Caledonia. Pacific Science(54) , p.39-55.
Uetz, P. (ed.) 2017. The Reptile Database.
IUCN 2021. The IUCN Red List of Threatened Species. Version 2021-2.
Bauer, A.M. and Sadlier, R.A. 2000. The Herpetofauna of New Caledonia.
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) , p.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) , p.283-301.
Experts
Assessor(s): Sadlier, R., Bauer, A., Jourdan, H., Astrongatt, S., Deuss, M., Duval, T., Bourguet, E., McCoy, S., Bouteiller, A., Lagrange, A.
Reviewer(s): Cox, N.
Contributor(s): Whitaker, A.
Facilitator(s): Lietar, J., Tanguy, V., Warimavute, G.