Taxonomy

endemique
protegee
UICN

Common name :

Le Gecko nain rayé du Koniambo Mt Koniambo Striped Dwarf Gecko

Red List Status -

Critically Endangered (CR) , assessed in 11/12/2017

Protected species -

in Southern Province , in Northern Province

Description

 

Description:

A small relatively stout species of gecko growing to a body length of 43mm. It has moderately broad toes. The colour pattern on the body is highly variable ranging from mid to dark brown above with a broad median region of paler greyish brown to almost uniformly coloured with a barely discernable lighter dorsal region.

 

Natural distribution:

Known only from Mt Koniambo in the northwest ranges.

Distribution within Province Nord: see above.

 

Habitat:

High elevation closed forest, and mid elevation maquis shrubland.

 

Threats:

  • moderate to high but localised level of threat to high elevation humid forest and gully forests through activities associated with mining.

  • moderate to high level of threat to remnant high elevation closed forest habitat through repeated firing of adjacent maquis habitat, leading to loss and degradation of the forest edge.

  • moderate to high level of threat to remnant high elevation closed forest habitat from grazing by deer and disturbance by pigs.

  • moderate to high level of threat to mid elevation maquis shrubland from fire.

  • moderate to high level of threat from predation by introduced rats, particularly if the species only persists in remnant patches of shrubland and forest in an already highly disturbed landscape.

 

Conservation Status: Critically Endangered

Dierogekko koniambo has an extremely restricted distribution (<100km2). The summit area of Mt Koniambo has been heavily impacted by mining activity. The species is already under threat from existing and proposed mining activity on the mountain which could result in a further decline in the area, extent and/or quality of the small areas of Montane closed forest habitat, furthermore this habitat is highly susceptible to catastrophic impact of wildfires. Maquis shrubland is also highly susceptible to the impact of repeated firing which results in a simplification of this habitat. As such the species has been identified as highly threatened and to meet the criteria to be categorised as Critically Endangered (Bauer et al., 2006).

 

*Species occurring in localised areas of maquis shrubland are highly susceptible to catastrophic impact of wildfires, and require pro-active conservation management to deal with this potential threat.


Dierogekko koniambo is listed as Critically Endangered because it has a very restricted distribution and there is continuing decline in its extent of occurrence, the extent and quality of its habitat and the number of mature individuals. This species is under high level of threat due to active mining operations and introduced species on the Koniambo massif.

Geographical area


Dierogekko koniambo is endemic to Province Nord, New Caledonia. It is known only from the Koniambo massif, northwestern Grande Terre. It occurs at elevations between 600 and 1,000 m. The extent of occurrence and the area of occupancy are estimated to be 12 km2.

Population


This species is presumed to have suffered a significant reduction in population size and extent with habitat loss and degradation resulting from wildfires, clearance for agriculture (low elevation) and past mining activities (mainly high elevation). Dierogekko koniambo is still locally abundant at some sites, but there are no quantitative data on population size or trends.

Habitat


This species inhabits rocky maquis shrublands and closed montane forest at mid- to high elevations on the Koniambo massif. It is nocturnal, arboreal, sheltering beneath stones by day and climbing into the vegetation at night.

Threats


The primary threat to Dierogekko koniambo is the development of a major nickel mine on the Koniambo massif which result in the loss of significant areas of habitat for this species. Wildfires are a constant threat, particularly in maquis shrublands, and there is widespread habitat degradation from introduced species impacting geckos (Jourdan 2014) such as deer and pigs. The introduced ant, Wasmannia auropunctata are expected to have a severe and potentially unsustainable impact on the geckos. Feral cats and rodents are also expected to exert a predation pressure on this species (Palmas 2017 and Thibault 2017).

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). This species is not present in any protected areas, therefore conservation measures are needed. Additional prospections are recommended.

Bibliography


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.

Thibault, M., Brescia, F., Vidal, E. and Jourdan, H. 2017. Invasive rodents, an overlooked threat for skinks in a tropical island hotspot of biodiversity. New Zealand Ecological Society(41) , p.74-83.

Uetz, P. (ed.) 2017. The Reptile Database.

IUCN 2021. The IUCN Red List of Threatened Species. Version 2021-2.

Jourdan, H., Brescia, F. and Vidal, E. 2014. Programme R_Mines.Impact des espèces invasives sur les communautés de reptiles des massifs miniers.

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.

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.

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): Warimavute, G., Tanguy, V., Lietar, J.


Geographical distribution