Research

Southern Whip-tailed Skink Tropidoscincus variabilis

Conservation status: Lower risk - least concern

Description: A moderately large species of skink growing to a body length of 78 mm, with very well developed limbs and a long tail 250% of the body. The scales of the body have three distinct keels. Adult colouration is dark overall with an orange ventral colour. Juveniles and sub-adults have distinctive yellow markings running along the side of the body.

Natural distribution: Moderately widespread throughout the south of New Caledonia. The species occurs in closed forest and maquis shrubland habitats over a broad latitudinal range.

Maquis shrubland - low and heath-like vegetation.

Distribution within Province Sud: Recorded from a number of sites ranging from the very south of the island north to Mt Vulcain. It has not been recorded from the northern half of the southern ultramafic block, which most likely reflects a general lack collecting in this area.

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

Threats:

• potentially high level of threat to closed forest populations with high infestation levels of introduced Fire Ants (Wasmannia auropunctata) causing significant decline in abundance
• potentially high level of threat to maquis shrubland populations in the south of the island from high infestation levels of introduced Crazy Ants causing significant decline in abundance
• moderate to potentially high 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
• moderate level of threat to 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 maquis shrubland through repeated firing resulting in a decline in quality of 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

Conservation status: Tropidoscincus variabilis occurs at 13 sites representing up to 10 sub-populations over the south of the island. Because of its relatively broad distribution the species does not satisfy the criteria required to place it at a level of threat. The species occurs in maquis as well as closed forest habitat suggesting the possibility of some connectivity between sub-populations, and therefore the potential for re-colonisation if once extinct. Threats leading to a continuing decline in both closed forest and maquis shrubland habitat have been identified above, but large areas of potentially suitable habitat subject only to minimal or no disturbance occur within the species range. For these reasons T. variabilis does not satisfy the criteria required to place it at a level of threat and most appropriately categorised as lower risk - least concern, and is not considered to be under any immediate threat. It is also likely to be recorded from additional locations after further survey work.

Future research required: none specifically recommended

• general survey work to more comprehensively document the species overall distribution, particularly in closed forest and maquis shrubland from Mt Vulcain north
• identification of distinct geographic units

Copyright © Australian Museum, 2002