Managing for climate change in the semi-arid zone

Background/Question/Methods

Arid and semi-arid regions make up a total of 33% of the earth’s landmass and provide a rich diversity of flora and fauna that are well adapted to the harsh environments. Climate change is likely to alter conditions in these regions but the impacts on biodiversity are unclear. Appropriately assessing species’ extinction risk under climate change is crucial for devising suitable adaptation strategies. Unfortunately the potential effects of climate change on species’ extinctions and ecosystem changes are poorly understood. Current predictions of species responses to climate change are largely based on projected bioclimatic changes and primarily address biota of humid climatic regions, while arid biomes remain comparatively neglected. Current predictions are incomplete as they fail to account for other important processes and interactions that may influence extinction outcomes. Species responses to climate change will also depend on the interaction between landscape, population and dispersal dynamics, species interactions, and existing stressors such as habitat degradation, fire and predation, particularly in the arid zone. We apply an integrated modelling framework to assess species extinction risk that incorporates interactions between population dynamics and landscape level processes in a changing climate. We couple time series of habitat suitability models with spatially explicit stochastic population models to explore factors that influence extinction risk under a stable and changing climate. We illustrate this integrated framework through the case study of Callitris verrucosa, a mallee pine in the semi-arid region of Australia. The species is sensitive to changes in altered fire regimes and threatened by grazing pressure. We investigate appropriate management strategies to ameliorate any negative effects of a changing climate on the species.

Results/Conclusions

Results indicate that complex interactions between life history, landscape dynamics and disturbance regimes influence species extinction risk under climate change. For Callitris verrucosa, managing fire return intervals and protecting seedlings from grazing pressure can offset and help reduce the added risk posed by climate change. This highlights the need to have methods that link population and landscape dynamics in order to highlight the processes and interactions that influence extinction risk greatest and can lead to the development of more effective management strategies that mitigate biodiversity losses due to climate change.