Are lizards toast? Climate warming, fire and lizard extinctions in the Australian arid zone

A collaborative project undertaken by The University of Melbourne and Australian Wildlife Conservancy and supervised by Michael Kearney

There is correlative evidence for recent range shifts and local extinction in association with climate warming. However, our understanding of the underlying mechanisms remains poor, making adaptive management difficult. One potential mechanism is restrictions on activity imposed by high temperatures. This mechanism was recently proposed to explain a spate of local extinctions in lizards across the globe, including the Great Desert Skink in Australia. However, the effects of climate change will likely be both direct and indirect, and will involve interactions with other threatening processes. What is lacking in this field is a means to fully integrate connections between climate change, habitat change (e.g. fire, food), individual responses (behavioural and energetic) and population responses (dispersal, inbreeding, population growth). Such an approach could provide key information for climate-relevant management decisions such as fire management, translocations, and where and when to survey for new populations. Our research will fill these gaps with novel and taxonomically generalizable techinques, which we will apply to better manage populations of arid zone lizards, with a specific focus on the Great Desert Skink.

In this project we will develop and apply an integrated approach for managing endangered arid-zone lizards in the context of climate change in interaction with other threatening processes, especially fire. We are achieving this by building a mechanistic model connecting thermal sensitivities, climate and habitat features, and integrating it with population dynamics models that can simulate different fire regime management strategies. We are applying the model to the Great Desert Skink at Newhaven Wildlife Sanctuary, a species thought to be vulnerable to extinction through changed climate and fire regime.

The aims of our study are:

  1. To estimate parameters for a mechanistic niche model of climatic constraints on the Great Desert Skink as a function of fire-induced vegetation change;
  2. To measure habitat suitability and as a function of fire history and to field-validate the predictions of the mechanistic niche model through microclimatic studies of Great Desert Skinks and their habitats under natural different fire successional stages;
  3. To integrate GIS-mapping and population dynamics approaches to understand the metapopulation dynamics of the Great Desert Skink in terms of the effects of climate and fire on habitat patchiness;
  4. To integrate the above knowledge into a decision-theory-informed management strategy of the Great Desert Skink at Newhaven Wildlife Sanctuary in the context of climate change.
Figure 1. Prescribed burning within semi-saline spinifex plains, preferred Great Desert Skink habitat on Newhaven Wildlife Sanctuary, a property managed by the Australian Wildlife Conservancy.
Credit: Josef Schofield/AWC

Figure 2. Great Desert Skinks are listed as Vulnerable under the EPBC Act.
Credit: Josef Schofield/AWC