Research

Common Litter Skink Caledoniscincus austrocaledonicus

Conservation status: Lower risk - least concern

Description: A small, surface active species of skink growing to a body length of 57 mm, with a tail 150% the length of the body, and well developed limbs. Colouration differs markedly between males and females but consists of shades of brown and grey with pale vertebral striping. Populations in the central and northern ranges and coast also have a pale mid-lateral stripe. The ventral surface of females and young of both sexes is typically yellowish, whereas adult males are red to orange underneath. The scales of the body have three distinct ridges or keels running along each scale.

Natural distribution: Widespread throughout New Caledonia over a wide latitudinal range, also present on offshore islands, the Isle des Pins, and Ouvea, Lifou and Mare Islands in the Loyalty Islands.

The species occurs in a range of natural and disturbed forest and shrubland habitat at all elevations.

Distribution within Province Sud: Widespread in the Province.

Distribution within Province Nord: Widespread in the Province.

Distribution within Province Loyalties: Present on Ouvea, Lifou and Mare Island, most likely widespread.

Threats:

• potentially high level of threat to closed forest and sclerophyll forest populations with high infestation levels of introduced Fire Ants (Wasmannia auropunctata) causing significant decline in abundance
• moderate level of threat to populations in sclerophyll and low elevation closed forest on the west coast from clearing for ranching or agriculture resulting in loss and further fragmentation of habitat
• moderate level of threat to isolated high elevation closed forest on ultramafic soils through activities associated with mining (particularly gully forests affected by mining spoil) resulting in a decline in area, extent and quality habitat
• low level of threat to populations in low elevation closed forest on the east coast from clearing for subsistence agriculture resulting in loss and further fragmentation of habitat
• low level of threat to mid elevation forest for timber plantations resulting in a decline in area, extent and quality habitat
• low level of threat to closed forest edge through repeated firing of adjacent savannah habitat resulting in a decline in area, extent and quality of habitat

Ultramafic - rocks that are dominated by minerals high in magnesium and iron, and which tend to be dark-coloured rather than pale.

Conservation status: Morphological and genetic studies indicate broad population sub-structuring comprising several major groups. One group occurs mainly in the south of the island over the southern ultramafic block, but has also recently been found in forest on ultramafic isolates in the north-west. A second occurs in coastal and near coastal habitats of west coast between Poya and Pindai. A third group occurs on the central and northern coast and ranges. These three geographically broad units correspond to genetic groups from a study of 20+ populations across the island using allozyme electrophoresis (Sadlier et al., unpublished).

Each of these groups has a relatively widespread distribution over large areas of potentially suitable habitat. The broad distribution of the species (including its component groups) in combination with its ability to persist in modified or disturbed forest or shrubland habitat indicate the species is most likely to be secure throughout its range.

However, preliminary studies indicate the presence of fire ants has a negative impact on Caledoniscincus austrocaledonicus in sclerophyll forest habitat. It is possible a similar impact might be experienced by the species in other areas infested with fire ants, resulting on localised declines or extinction.

Allozyme electrophoresis - a genetic technique which uses an electric current to separate proteins to differentiate closely related species.

Future research required:

• identification of distinct geographic units
• the level of impact of introduced fire ants on populations in moist closed forest habitat

Copyright © Australian Museum, 2002