Susceptibility of social species to population decline in changing environments

Environmental variation plays a fundamental role in limiting natural populations. Understanding the complexity behind this seemingly simple observation is of fundamental interest to population ecologists, as well as having increasing practical importance as we attempt to manage the adverse effects of anthropogenic environmental change. An important driver of environmental change affecting wild populations is loss and degradation of habitat, leading to altered availability and distribution of food resources. The responses of animal populations to such changes are strongly dependent on social structure, particularly as it determines the way in which individuals' behavioural interactions influence their access to resources. For example, important non-linearities in population responses to environmental change are likely to arise as a result of such behavioural interactions, particularly in highly social species. A strong predictive understanding of animal population responses to a changing environment therefore requires a knowledge of how individuals' behaviour responds both to resource availability and to other individuals in the population. In light of these complexities, the purpose of this studentship is to develop a general framework for understanding when environmental change will exceed behavioural tolerances for social species. The development of such a framework will make an important contribution to our ability to anticipate and manage such processes. The work will be carried out in four cumulative steps, each of which will also comprise a substantial research activity in its own right. Step 1. Studying social foraging decisions in a patchy environment. Fieldwork will be carried out to collect observational data on individual patterns of social foraging among desert baboons Papio ursinus. Data will be collected on individual foraging success and group level responses in relation to the physical and social conditions. This will provide crucial context for the development of the next step. Step 2. Developing an individual-based model of social foraging. A spatially-explicit individual-based model of patch use will be developed to provide a framework for predicting the influence of environmental change on group dynamics and individual foraging performance. These predictions will be validated using observational data from the previous step, and further tested using experimental data gathered in the following step. Step 3. Experimental tests of the individual-based model. In these experiments, resource configuration will be manipulated in natural food patches. These trials will be designed to push the range of resource configurations beyond those observed naturally, providing a strong test of the predictive power of the model. Step 4. Exploring social species tolerances to environmental change. The individual-based model will be designed with sufficient flexibility to allow key elements of the food patch configuration and social structure to be altered to reflect gradients observed across species. This final phase of the project will be a theoretical exploration of the ways in which these gradients influence patterns of group dispersion and foraging success under environmental stress. The results will be used to identify basic principles about how environmental change may affect different types of social species, and so provide a predictive framework for future study and for application in population management. The student will benefit from the CASE partnership through access to the resources of a well established long-term research site, including a number of baboon troops that are well habituated to the presence of observers, and considerable in-kind support through the provision of essential equipment. The supervisory team will provide a strong combination of theoretical, technical and field-based expertise, as well as world-class learning environments at their respective institutions.