Effects of climate change on a reptile community in arid Australia

Project leadership: Prof. Dr. Klaus Henle
Staff responsible: Dr. Annegret Grimm-Seyfarth, Michele Chiacchio
Cooperation partners: Institute for Applied Ecology, University of Canberra
Contact person: Dr. Annegret Grimm-Seyfarth
Project duration: since 2012

Project description

Within the past decades, global mean temperature has exceptionally increased and precipitation became more variable with extreme events increasing in frequency. Strong evidences already suggest that climate change has considerable impact on biodiversity. However, species respond differently due to specific life-history traits and because climate change is not uniform across the globe. Thus, responses also differ between ecosystems. While most studies are focussing on temperate regions and tropical systems, little is known in hot arid ecosystems, which harbour a high and mainly endemic terrestrial biological diversity.

Typical natural habitat of the arboreal gecko.
Typical natural habitat of the arboreal gecko Gehyra variegata.
One of the studied species: Gehyra varioegata
One of the studied species: Gehyra variegata.

The largest part of vertebrate diversity in hot deserts is represented by reptiles. As any ectotherms, reptile metabolism and biology are tightly linked to external temperature, making them particularly sensitive to climate change. Beside direct effects associated to changes in temperature and precipitation, vegetation cover and predators are important but largely under-documented drivers of reptile populations.

Taking advantage of a long-term monitoring study on a lizard community in the eastern margin of the arid zone of Australia, we will quantify the relationship between lizard ecology and different direct and indirect effects (via vegetation and predators) of climate in the arid zone of Eastern Australia during the last 30 years. We will then project future population trajectories under existing driver scenarios. Australia’s arid zones are particularly suitable to study the effects of climate change since this region is particularly sensitive to climate-related changes via global climate change and El Nin᷉o Southern Oscillation (ENSO), the latter resulting in droughts (El Nin᷉o) and floods (La Nin᷉a). Analyses will comprise estimating the relationships of trends in lizard population sizes, demographic parameters, and trends of lizard community composition with changes in temperature, local rainfall, predator abundance, vegetation cover, and ENSO driven extreme events. We will further investigate how demographic parameters are linked to thermal restrictions of activity, a mechanism that is a key assumption of current models predicting global effects of climate on reptiles. We will finally integrate such mechanistic understanding using state of the art approaches in process-based matrix modelling to project the future impacts of climate change on lizards in arid Australia.

Ctenotus regius
The ground dwelling skink Ctenotus regius
Lucasium damaeum
Ground-living gecko Lucasium damaeum