In recent years an increasing number of studies have documented phenological responses to climate change in wild animals. However, while most studies have focussed on individual life history traits we know that natural selection acts on whole phenotypes and organismal impacts of environmental change are mediated by complex causal pathways among traits . Thus to understand the evolutionary and ecological consequences of environmental change we need multivariate modelling strategies that integrate across life-history, morphology, behaviour and physiology. This integration is essential to understand population level processes, and without it demographic predictions for wildlife management and conservation objectives will be flawed. The primary goal of the proposed research is to develop and apply such an integrative approach, quantifying the relationship between multivariate phenotypic selection and environmental parameters (e.g. spring temperature), and determining the consequences of environmental change for trait distributions, life history trade-offs and population dynamics. Using an exceptional long term dataset that spans more than 50 years of research on wild yellow bellied marmots, I will employ cutting-edge analytical methods to identify causal relationships among traits, decompose them into genetic and environmental components, and quantify their contributions to (genetic) variance in fitness. The project will be carried out in the group of Dr. Wilson (CEC, University of Exeter), where I will receive a thorough training in evolutionary quantitative genetics from one of the global leaders in this field. At the same time I will also bring new analytical skills and knowledge that directly benefit his research program, other scientists at the University of Exeter, and the wider European research community. This project should lead to strong publications and will serve to establish long-term collaborations between European and North-American researchers.