This species is listed as Endangered because it has a restricted distribution with an estimation of only four locations and there is continuing decline estimated in its area of occupancy, extent and quality of its habitat and number of mature individuals due to a variety of threats.

Geographical area

This species is endemic to Province Nord, New Caledonia. It is known from three localities on the central east coast of Grande Terre between Houaïlou (old record) and Poindimié (Pont Tamanou, Koyaboa, Pic Amoa). Although surveys in other areas have so far failed to find additional populations, it is expected to occur more widely as extensive areas of habitat remain. It occurs at elevations between 100 and 500 m. The extent of occurrence is estimated at 532 km² and the area of occupancy at 16 km².

Population

Although there are no quantitative data on population size and trends, the population of this skink on Mount Koyapwa, Poindimié, completely collapsed following the arrival of Wasmannia auropunctata at the site and may now be locally extinct (Sadlier et al. 2002). Recent observations report it as a relatively common species between Koyaboa and Pont Tamanou.

Habitat

This species inhabits closed humid forest. It is cryptozoic, semi-fossorial; terrestrial. It shelters beneath logs and stones and forages through leaf litter.

Threats

The greatest threats to Nannoscincus greeri appear to be further habitat loss and the effect of the introduced ant Wasmannia auropunctata. Closed humid forests at low to mid-elevation are increasingly fragmented on the central east coast and any further clearance for agriculture, afforestation or logging, or destruction by wildfires, will lead to further reductions in extent and population size, and possibly local extinction. Wasmannia auropunctata is now widespread through the range of Nannoscincus greeri but is likely to be having a continuing effect. Habitat degradation by introduced ungulates (deer and pigs), leading to lower humidity, and from pigs disturbing the litter layer and cover are other significant issues, and predation by rodents (Thibault 2017) may be a risk.

Conservation

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). It is not present in any reserves and no conservation management is currently being undertaken. The Povila area would deserve a protection status while field work in the Houaïlou valley and Yahoue Valley near Poindimié would help confirm the possible presence of this species.

Bibliography

Sadlier, R.A., Bauer, A.M. and Whitaker, A.H. 2002. The scincid lizard genus Nannoscincus Günther from New Caledonia in the southwest Pacific: a review of the morphology and distribution of species in the Nannoscincus mariei species group, including the description of three new species from t. Zoologia Neocaledonica 5, Mémoires du Muséum national d’Histoire naturelle(187) , p.233-255.

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.

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.

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

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.

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.