Individual strategies, group dynamics and population regulation in singular cooperative breeders

Most detailed studies of the regulation of population density in birds and mammals have focussed on studies where recruitment and survival decline as population density increases, eventually limiting population size. However, in some species, recruitment and survival increase with rising density, generating positive correlations known as Allee effects. Empirical studies show that effects of this kind are more widespread than was previously thought though our understanding of their causes and ecological consequences is still very limited. These effects appear to be particularly pronounced in cooperative breeders where one female in each group monopolises reproduction and non-breeding adults assist her to raise her offspring but, although studies have commonly investigated the evolution of reproductive strategies in these species, the ecological mechanisms controlling group size and population density have rarely been explored. This study will investigate the ecological processes limiting group size and population density in singular cooperative breeders using wild Kalahari meerkats (Suricata suricatta) as a model. It will test the prediction that positive correlations between group size and breeding success are a consequence of increases in the ability of group members to detect predators and will determine whether group size is limited by increasing rates of dispersal by subordinate females, caused by increasing intolerance by dominant females living in large groups. It will explore the effects of regulatory processes at the group level on dynamics and demography at the population level. Finally, it will investigate how group size and population dynamics are affected by variation in rainfall, food availability and disease. By exploring the unusual ecological mechanisms affecting population dynamics in meerkats, the project will provide an informed basis for the management and conservation of other animals subject to strong Allee effects.