AbstractIntroduction and aims:
Great desert skinks (Liopholis slateri) are unique Australian desert lizards that build and inhabit communal burrows. They are listed as vulnerable under the EPBC Act 1999 and uncontrolled wildfire and introduced predators are considered to be key threatening processes. Particularly, it is thought that reduced cover associated with fire makes skinks more vulnerable to predation. One of the stronghold populations for the species at Uluṟu-Kata Tjuṯa National Park (UKTNP) has been significantly affected by wildfire in the past decade. Patch burning is currently implemented around known great desert skink burrows at UKTNP to prevent further wildfires occurring. In this thesis I examine the distribution, habitat selection and behaviour of great desert skinks in relation to fire, vegetation cover and other habitat attributes. I aimed to test whether (a) the distribution of great desert skinks at UKTNP is linked to specific fire regimes, (b) active skink burrows are associated with particular vegetation or soil attributes, and (c) the behaviour and activity levels of skinks, including their response to predators, varies depending on the vegetation cover at burrows.
I conducted systematic, replicated, unbiased searches for skink burrows in three different fire histories (recent wildfire, prescribed burn areas, and 12 year unburnt) and in accordance with the current and past known distributions of skinks in the park. To assess habitat selection, I chose 59 active burrows, approximately 70% of the known active population in the park. Vegetation cover and soil surface assessments were made at burrows and at paired control sites with no burrows. Twelve burrows with different vegetation were selected for behavioural observations. Activity of great desert skinks and predator visits at the main entrances of these burrows was monitored using time lapse photography; one photo per minute for 18 days in each of the early and late active seasons. Comparative use of entrances within a single burrow system was investigated at two additional burrows over four days in the late active season.
Results and conclusions:
Only eleven burrows were found in over 90km of searching and this low success rate made it impossible to draw specific conclusions about skink distribution in relation to fire at UKTNP. However, comparisons between habitat attributes at burrows and controls suggested skinks may be selecting for higher cover, as burrow sites had significantly higher cover and were more likely to be associated with shrub species than control sites. Soil properties also differed between burrows and control sites. Activity of great desert skinks was highly variable among burrows, as was predator occurrence. I found no significant relationship between vegetation cover and predator visits to burrows or the response of skinks to predators. There were also no significant differences in overall activity between burrows with high and low vegetation cover, however skinks spent proportionally more time exposed (outside the burrow) when cover was greater at the burrow or particular entrance. This may represent an adjustment of behaviour in response to the perceived threat of predation.
|Date of Award||Jun 2015|
|Supervisor||Christine Schlesinger (Supervisor) & Michael Bull (Supervisor)|