There is increasing concern that recent declines in many wild populations are linked to climate change and other human-induced pressures, such as habitat management, harvesting, invasive species and disease. Population-level changes in the face of anthropogenic change are underpinned by individual-level responses, and recent work suggests that individual variation in responses of a range of life history traits is a common phenomenon in wild populations. Moreover, interpreting population-level patterns in relation to environmental change in the absence of understanding of individual-level variation can lead to inappropriate conclusions.
The intrinsic drivers of individual-level change in the key life-history traits that determine demography are poorly understood. Factors such as sex, age and reproductive history are known to be important, and interactions between such factors and the environment have been shown to affect fitness-related traits. However, it is less clear whether these result from within-level change or between-individual change caused by selective appearance or disappearance of phenotypes. Understanding how and why individuals vary in their response to external pressures and how any such variation affects demographic rates is a fundamental question in population ecology. It is also relevant to evolutionary and conservation biology, since populations can adapt if individuals that are better equipped to cope with novel conditions produce more offspring, and future generations inherit their abilities.
Working on seabird study systems, my research focuses on disentangling the intrinsic and environmental drivers of the dynamics of wild animal populations. My approach is to quantify the variation in individual behavioural and physiological traits that relate to fitness, combining empirical data collection with statistical modelling of long-term individual-based data sets to address the following questions: