DISSERTATION RESEARCH: Eco-Evolutionary Effects of an Aquatic Consumer: Linking Phenotypic Diversity to Community and Ecosystem Responses

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This research addresses the interaction between ecological and evolutionary processes by examining the recent evolution of a common invasive fish species, the white perch, in lakes and the consequences of this evolution for community and ecosystem dynamics. White perch have successfully invaded lakes spanning a productivity gradient, which provides diverse selective pressures that may result in altered fish morphology, physiology and ecological role. Adaptation by these fish may, in turn, feed back to affect lake productivity and community structure through several ecological and chemical pathways. This project tests the hypothesis that this rapid evolutionary divergence within a single species has resulted in ecological effects that are large relative to longer term divergence between different species of fish. The research will use controlled rearing of fish from differing lakes to establish the genetic nature of the relationship between lake productivity and fish traits that include body chemistry, body shape, and feeding morphology. In additional, mesocosm experiments will be used to determine the effects of fish trait variation on plankton community structure and ecosystem processes such as nutrient cycling and productivity. By using mesocosms seeded with plankton and fish from different source ponds, fish and plankton source treatments will be crossed and the relative impact of fish invasion into novel habitats will be compared to longer term evolutionary divergence. This research tests an ecological-evolutionary framework that is a recent synthesis between evolutionary biology and ecology. This framework has the potential to provide general insight into the causes and consequences of biodiversity and a better understanding of the pace at which evolution and ecology interact. This theoretical framework and research that uses a common fish invader informs practical issues involving management and conservation of biodiversity and maintenance of water quality in lakes. This project will enhance the doctoral thesis of a graduate student and provide several undergraduate students with research experience.