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An investigation of potential threatening processes for the Vulnerable great desert skink, Liopholis kintorei
thesisposted on 2022-03-28, 21:22 authored by Danae Moore
Although there is a great body of knowledge regarding the status of and threats to extant mammal populations in Australia there remains limited comparable information on reptiles. One in five reptilian species are threatened with extinction globally, with one in four species of Australian reptile considered to be in decline. Several prominent threatening processes have been identified as being the likely cause of reptile population declines and local extinctions including: 1. grazing history; 2. human induced habitat loss and fragmentation; 3. habitat homogenisation caused by changes in recent fire regimes; 4. increased predation pressure caused by the introduction of cats and foxes; 5. harvesting, and more recently; 6. climate warming. Since European settlement within Australia only a single record exists of an Australian reptile becoming extinct-Christmas Island forest skink (Emoia nativitatis) in 2014 however, ten reptile species are listed under the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999 as Critically Endangered, 20 as Endangered and 33 as Vulnerable. Of these, at least six species are arid zone specialists, including the great desert skink Liopholis kintorei, which is nationally listed as Vulnerable. Liopholis kintorei is a large social skink that constructs complex burrow systems. Although its known distribution covers a significant area of arid Australia-1 500 000 km², it is Nationally listed as Vulnerable with approximately seventy known discrete populations with observed localised population declines or extinctions. Several potential threatening processes have been identified: 1. habitat alteration caused by recent changes to fire regimes; 2. increased predation pressure caused by the introduction of the feral cat and European red fox, and more recently; 3. climate warming. However, no supporting field data are available to confirm these as threatening processes, and as such the underlying mechanism driving the observed declines are yet to be explored. I investigated the threatening processes previously identified for this species. Specifically, I aimed to: 1. examine the effect of fire on L. kintorei burrow-system occupancy and breeding success at different spatial and temporal scales; 2. identify predators of L. kintorei and assess potential predator pressure at the burrow system; 3. further understand the potential role of climate warming as a threatening process by examining current and future thermal constraints on L. kintorei activity patterns. In addition, I aim to increase our understanding of L. kintorei dispersal patterns by characterising age- and sex-based patterns of within-patch movement, philopatry and dispersal. This knowledge is critical for guiding effective conservation. This research identifies the key threatening processes for L. kintorei within spinifex grasslands and contributes to our understanding of L. kintorei dispersal patterns. It will be necessary for key populations across its wide distribution to be formally identified and these key threats actively managed to ensure that the distribution of this species does not continue to decline significantly.