Taxonomy
Common name :
Le Bavayia à bande nette
Bold-Stripe Bavayia Red List Status -
Endangered (EN) , assessed in 11/12/2017Protected species -
in Southern Province , in Northern Province
Description
Description:
A small relatively stout species of gecko growing to a body length of 45mm, with a short tail 110% the length of the body; moderately broad toes; and a colour pattern on the body that is typically brownish above with a broad and bold lighter vertebral stripe.
Natural distribution:
Far northeast ranges of New Caledonia.
Distribution within Province Nord: Restricted to Province Nord and known only from two locations, Mt Panié and Mt Mandjélia.
Habitat:
Low-mid elevation humid forest.
Threats:
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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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low level of threat to low elevation humid forest on the east coast through loss, modification and fragmentation of forest habitat to local agriculture.
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low and localised level of threat to mid elevation humid forest through loss and modification of forest habitat (Mt Mandjélia) to timber logging.
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low level of threat to humid forest habitat through repeated firing of adjacent savannah habitat, leading to loss and degradation of the forest edge.
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potentially high level of threat from exotic pests such as rats and cats (predation of adults, young & eggs) in heavily affected areas.
Conservation Status: Vulnerable.
Dierogecko validiclavis has a very small distribution on the northern ranges is considered to represent a single continuous population along the range within some of the least disturbed and most pristine closed forest habitat in New Caledonia – its likely area of occupancy is <100 km2. Fire ants are present at Panié at low elevation and several threats that affect the area, extent and quality of habitat have been identified, particularly at the closed forest edge, but for most of its distribution Dierogecko validiclavis occurs within closed forest habitat subject to little disturbance. The species' small distribution, in combination with several moderate to high level threat indicates it is at risk, and satisfies the criteria to be categorised as Vulnerable.
Dierogekko validiclavis is listed as Endangered because it has a restricted distribution, it is found in two locations, and there is continuing decline in its area of occupancy, the extent and quality of its habitat and the number of mature individuals.
Geographical area
Dierogekko validiclavis is endemic to Province Nord, New Caledonia. It is known only from a single population (the Panié massif, north-eastern Grande Terre). Confirmed from just two sites—Mt Mandjélia and Mt Panié, 35 km apart— but the species is expected to be widely distributed along the massif between these two locations as the habitat is continuous and relatively undisturbed. It occurs at elevations between 300 and 500 m. The extent of occurrence is estimated to be 71 km2 and the area of occupancy is estimated to be 20 km2.
Population
There is no information on present population density or trends for Dierogekko validiclavis. This species may have suffered some reduction in range and population size as a result of habitat loss on the lower slopes of the massif through wildfires and clearance for agriculture.
Habitat
Dierogekko validiclavis inhabits closed humid forests. It is nocturnal and arboreal, sheltering by day beneath stones and logs and climbing into subcanopy trees and shrubs at night.
Threats
The major threats on Dierogekko validiclavis are predation pressure from feral cats (Palmas 2017) and the introduction of fire ant, Wasmannia auropunctata, which is present in forests at lower elevations and is expected to have a severe and potentially unsustainable impact on the geckos (Jourdan et al. 2000, 2001). Wildfires are a constant threat on the lower slopes and may affect some habitat by damaging forest margins. Habitat degradation is also occurring in forest interiors from introduced ungulates such as deer and pigs (Jourdan 2006).
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). Dierogekko validiclavis is present in the Réserve de Nature Sauvage du Mt Panié. No conservation management is currently being undertaken to this species, but it may potentially benefit from proposed predator control in the La Guen catchment on Mt Panié.
Bibliography
Sadlier, R.A. 1989. Bavayia validiclavis and Bavayia septuiclavis, two new species of gekkonid lizard from New Caledonia. Records of the Australian Museum(40) , p.365–370.
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.
Palmas, P., Jourdan, H., Rigault, F., Debar, L., De Meringo, H., Bourguet, E., Mathivet, M., Lee, M., Adjouhgniope, R., Papillon, Y. and Bonnaud, E. 2017. Feral cats threaten the outstanding endemic fauna of the New Caledonia biodiversity hotspot. Biological Conservation(214) , p.250-259.
Bauer, A.M., Jackman, T., Sadlier, R.A., Whitaker, A.H. 2006. A revision of the Bavayia validiclavis group (Squamata: Gekkota: Diplodactylidae), a clade of New Caledonian geckos exhibiting microendemism. Proceedings of the California Academy of Sciences(57) , p.503–547.
Uetz, P. (ed.) 2017. The Reptile Database.
Bauer, A.M. and Sadlier, R.A. 2000. The Herpetofauna of New Caledonia.
IUCN 2021. The IUCN Red List of Threatened Species. Version 2021-2.
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., Warimavute, G., Tanguy, V.