The role of landscape structure in determining eco-evolutionary dynamics during environmental change

Abstract

Climate change may produce a variety of responses in populations' ecological and evolutionary dynamics. At opposing limits of populations' ranges, the responses are expected to differ. Some lag in response may be expected due to the rapidity of climate change, with the strength and type of lags varying across space. Importantly responses may contain both ecological and evolutionary components. This thesis provides significant contribution to understanding how structure in populations and the landscape may determine the nature of populations' responses to climate and environmental changes. A number of models and a microcosm experiment are presented. The results show how alternate temporal and spatial population structures are developed when individuals move in space. From defining percolation routes, patterns of gene flow or spatial selection, landscapes provide a large role in determining populations' responses. Even without landscape structure, populations exhibit large levels of regional structure, and indeed substructure, due to localised interactions. This spatial structure may deform during climate change, producing new characteristics of equilibrium spatial distributions. During range deformation the feedback between spatial structure and dynamics can alter populations' evolvability by changing the patterns and strength of intraspecific competition, or the maintenance of genetic variation. These changes produce dynamics that will be sensitive to individual differences in a population. Changes in populations' age and sex structure may modulate ecological and evolutionary interactions. The research presented here highlights an increased importance of understanding populations' spatio-temporal structure and dynamics within heterogeneous landscapes. This is especially so as ecological and evolutionary processes can converge to different degrees during climate change, depending on the landscape a population inhabits. Prediction of populations' responses may require a greater understanding of spatial processes and how range deformation affects the evolution of different kinds of traits. All the above areas feed into a greater understanding of the genesis and maintenance of diversity in any situation