Listed as Critically Endangered because of its highly restricted distribution, all individuals are in a single population, and there is continuing decline in the extent of occurrence, area of occupancy, extent and quality of its habitat and mature individuals. Surveys of surrounding areas with suitable habitat have not encountered this species and so it is imperative that its only location is protected. The species is moisture dependent and habitat is vulnerable to prolonged drought.

Geographical area

Nannoscincus hanchisteus is endemic to Province Nord, New Caledonia. It is known only from a small remnant of closed sclerophyll forest on the Pindaï Peninsula on the north west coast of Grande Terre (Bauer and Sadlier 2000, Sadlier et al. 2002). It occurs at elevations up to 60 m. The extent of occurrence and the area of occupancy are estimated to be 4 km².

Population

There are no quantitative data on population size and trends for Nannoscincus hanchisteus but it appears to be localised and very uncommon. It is assumed to have undergone a dramatic reduction in area of occupancy as a result of the destruction of sclerophyll forest in the immediate area of Pindai and possibly elsewhere on the central west coast as a result of clearance and wildfire - the true extent of the population pre-human will never be known. Recurrent wildfires in the adjacent savanna and the presence of high-density populations of the invasive ant Wasmannia auropunctata at the only known site mean the population is expected to be declining in both extent and density.

Habitat

Nannoscincus hanchisteus is found in sclerophyll forests (Sadlier et al. 2002). This species is cryptozoic, semi-fossorial, and chooses the moistest habitats within the rather mesic sclerophyll forests (Bauer and Sadler 2000). It shelters beneath stones and litter, and forages through leaf litter.

Threats

The greatest threats to Nannoscincus hanchisteus are the high vulnerability of the remaining sclerophyll forest habitat to wildfires and the introduced ants, Wasmannia auropunctata, which have detrimental impact as it is known to decimate lizard populations (Jourdan et al. 2000, 2001). Habitat degradation by introduced ungulates (deer and pigs), leading to lower humidity, and from pigs disturbing the litter layer and cover are other significant concerns. Predation by rodents may be a risk (Thibault 2017) as well as by cats (Palmas 2017). There is also a very high-density population of the African snail Achatina fulica at the site and the long-term consequences of this on the vegetation composition and structure, and litter stability are not known. Even if N. hanchisteus is found to occur in other sclerophyll remnants in the area, these are likely to be highly vulnerable to clearance for agriculture or degradation by livestock.

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). Not listed on CITES. It is not present in any protected areas but part of Pindaï sclerophyl forest is actively managed by the Conservatoire d'Espaces Naturels. No species conservation management is currently being undertaken.

Bibliography

Morat, P.; Jaffré, T.; Tronchet, F.; Munzinger, J.; Pillon, Y.; Veillon, J.-M. and Chalopin, M. 2012. Le référentiel taxonomique Florical et les caractéristiques de la flore vasculaire indigène de la Nouvelle-Calédonie [The taxonomic database « FLORICAL » and characteristics of the indigenous flora of New Caledonia]. Adansonia sér 3(34) , p.177-219.

Hallé N.; Aubréville A.; Leroy J. F.; 1977. Flore de la Nouvelle-Calédonie et dépendances. Volume 08 : Orchidaceae.

Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.

Experts

Assessor(s): Butin, J., Laudereau, C., Antheaume, C., Cazé, H., Garnier, D., Fleurot, D., Letocart, D., Letocart, I., McCoy, S.

Reviewer(s): Tanguy, V.

Facilitator(s): Chanfreau, S.