Document ID: chunk:federal_register_of_legislation:F2006L03939:body:0:p6
Version: federal_register_of_legislation:F2006L03939
Segment Type: other
Provision Reference: 
Character Range: 15010–17890

dismissed. Without locating and regularly monitoring any remaining populations, as proposed in this Recovery Plan, pathogenic mortalities have little chance of being identified.

Competition
The introduced geckos Hemidactylus frenatus and Gehyra mutilata are both arboreal and feed on small arthropods, and so are potential competitors with Lister's Gecko. These species tend to occupy more disturbed habitats, but the occurrence of both at sites in 1998 that were occupied solely by Lister's Gecko in 1979 (Cogger & Sadlier, 2000) suggests either that they have succeeded in displacing it or have moved into such areas following the latter's decline from other causes.

Currently there is no information available on potential competition between the blind snake and the introduced Flowerpot Snake (Ramphotyphlops braminus). Both are primarily fossorial species feeding mostly or solely on the eggs, larvae and pupae of ants and termites, indicating that there could be significant competition for food and preferred space.

Both Lister's Gecko and the blind snake are likely to compete with the crazy ant. The latter preys on a wide range of invertebrate taxa, including all taxa likely to be eaten by both the gecko and the blind snake.

Crazy Ant control measures
The insecticide fipronil is currently used to control populations of the Yellow Crazy Ant on Christmas Island. Although fipronil is relatively toxic to a range of reptilian species (Peveling, 2000; Tingle and McWilliam, 1999), it has been used in what are considered to be safe dilutions for non-target species, and there is no evidence that fipronil at the concentrations used has an effect on the reptiles of Christmas Island. Trials of manual and aerial baiting with fipronil have included pre-and post-baiting surveys of the impact of baiting on non-target species, including reptiles (Stork et al., 2003), however no individuals of Lister's Gecko or the blind snake have been seen in any of these surveys and so the effects, if any, of baiting programs on these species are unknown. While it may well be that the overall impacts of the crazy ant on the Christmas Island biota are so severe that their control would be given priority over the conservation of any individual species, there is some potential for the control program to impact on both Lister's Gecko and the blind snake. Alternatives methods are currently being explored, including the use of insect growth regulators instead of insecticides.

Displacement from preferred habitat by the crazy ant
It is likely that both Lister's Gecko and the Christmas Island Blind Snake, like other endemic reptiles, are displaced from their habitats within areas grossly affected by ant supercolonies through physical distress when traversing areas with swarming ants, through olfactory responses to ant secretions in gecko-ant and snake-ant interactions, or