Hot Birds Research Project

Endotherms inhabiting hot, arid environments are particularly vulnerable to the effects of climate change. Organisms can potentially adjust their physiology, behaviour, morphology and/or geographic distribution in response to climate change, although their capacity for such adjustments may be constrained by biotic and/or abiotic factors. Thus organisms and their physical environments interact giving rise to selection pressures which shape their distribution, physiology and morphology over time. Traditionally, models of species responses have been purely correlative (e.g. climate-envelope models), based on the assumption that the subset of climatic variables currently experienced by a species is an accurate predictor of future distribution under the effects of climate change. Such an approach is limited as it is devoid of physiology and behaviour. In contrast, mechanistic models predict future species distributions based on behavioural, physiological and microclimate data. Establishing mechanistic links between resource availability, foraging behaviour, individual fitness and population dynamics requires extensive knowledge on complex animal-environment interactions mediated by physiological processes at the individual level. These two approaches can be thought of as a continuum from 1.) broad-scale, multispecies applications based on climate-envelope models  to 2.) fine scale, single species studies based on mechanistic models. Both climate-envelope and mechanistic models have advantages and limitations, however the potential for a middle ground approach exists. The aim of my PhD is to develop a middle ground, novel modelling approach integrating the thermal landscape, heat and water fluxes and behavioural decisions and trade-offs for desert birds currently and under future climate change scenarios. I further intend to validate the model using existing datasets for the physiology and behaviour of southern African species (e.g. Southern Pied Babblers, Southern Yellow-billed Hornbills). The ultimate objective is to be able to construct detailed models of survival and reproduction in birds, reducing the need for detailed species-specific empirical datasets to predict avian responses to climate change.