Research

Gracile Bavayia Bavayia gietiana

Conservation status: Vulnerable

Description: A medium species of gecko growing to a body length of 72mm and tail 144% that of the body. It has moderately broad toes. The colour pattern on the body is typically brown above with 5-8 darker pale-edged blotches.

Natural distribution: southern New Caledonia.

Distribution within Province Sud: Restricted to Province Sud and known only from closed forest south of Mt Dzumac.

Threats:

• potentially high level of threat to populations in areas with high infestation levels of introduced Fire Ants (Wasmannia auropunctata) causing significant decline in abundance
• moderate to high level of threat to isolated closed forest on ultramafic soils through activities associated with mining (particularly gully forests affected by mining spoil) leading to a decline in area, extent and quality habitat
• moderate to high level of threat to closed forest edge through repeated firing of adjacent savannah and maquis habitat leading to a decline in area, extent and quality of habitat
• localised but potentially high level of threat from exotic pests such as rats and cats (predation of adults, young and eggs) on populations in closed forest habitat adjacent to urban development
• localised but potentially intensive decline in area, extent and quality of closed forest habitat adjacent to urban development

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

Conservation status: Bavayia gietiana occurs at five locations each representing an isolated sub-population. Current research indicates little genetic variation between distinct geographic units. The distribution of the species as it is known satisfies the criteria for a small distribution (area of occupancy <500km2), but it could possibly be recorded from other areas of closed forest habitat with further survey work. The species appears to have very specific microhabitat requirements, and is usually recorded from areas of forest with extensive outcropping rock on the forest floor. The occurrence of B. gietiana elsewhere in the region will most likely be determined by the availability of this particular type of sheltering site.

Three of the four locations from which the species has been recorded lie within reserves, which afford some degree of protection to the area, and the extent and quality of preferred habitat. However, over parts of its range the species preferred habitat is present as isolated remnants. It is also one of most highly developed regions in New Caledonia. The sub-population on Mt Koghis by virtue of its proximity to urban development is vulnerable to a range of threats associated with urban encroachment ie. fire; land clearing; pressure from exotic pests such as rats and cats, while the sub-population at Kwa Neie (Foret Nord) is in very close proximity to the Goro Nickel mining encampment. Introduced Fire Ants (Wasmannia auropunctata) are present at two locations (Mt Koghis and Riviere Bleue) and the potential threat to the populations of gietiana at these and other locations needs to be determined.

Given the species overall small distribution, much of which consists as small, fragmented isolates, in combination with a suite of threats which impact on the area, extent and/or quality of habitat, Bavayia gietiana satisfies the criteria to be categorised as Vulnerable.

Future research required:

• undertake targeted survey work to more comprehensively document the species overall distribution
• assess the extent of decline in area and/or quality of forest habitat in which it occurs
• assess the extent of spread of the fire ant on infested sub-populations

Copyright © Australian Museum, 2002