Factors affecting niche and genetic subdivision in animal populations

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My research program investigates resource use by aquatic animals, and how their niche changes in response to human activities. In addition, I use genetic tools to understand whether groups of animals are connected or disjunct from one another, and to help delineate appropriate geographic scales for management and conservation planning. In the proposed program my group will use next-generation DNA sequencing to examine genetic relationships among walleye and sauger populations across major watersheds in central Canada. At the same time, we will characterize niche overlap between these species using biochemical markers (stable isotopes), and determine the potential importance of niche overlap in producing hybrid saugeye. An important aspect of the research is assessing the potential for human-made reservoirs to change levels of niche overlap by putting walleye and sauger together in a novel environmental context. The proposed program will also use biochemical markers to examine niche overlap between fish-eating double-crested cormorants and predatory sport fish. We are specifically interested in determining whether human over-exploitation of walleye has freed-up niche space for cormorants, providing a general mechanism for cormorant population growth and expansion via niche replacement. In other words, we wish to determine whether cormorants become “flying walleye” when humans create the opportunity for them to do so. The proposed program will also take advantage of archived biochemical and genetics datasets to examine patterns between the two types of investigations using lake and round whitefish as test subjects. My research will contribute to science by advancing our knowledge and perspective on how human activities influence aquatic animal niche and shape ecological interactions. Moreover, it will provide novel insights into the genetic delineation of fish populations and detection of hybrids. The proposed program deals extensively with economically important species; walleye, sauger, and whitefish are key components of the multi-billion-dollar freshwater fishing industry in Canada, and cormorants are persecuted because of perceived impacts on this extremely valuable resource. Thus, it is imperative that we have the best supporting science available to aid management decisions. The proposed program is expected to help guide appropriate policy around aquatic habitat alterations, fish management and stocking, and the approach to cormorant/fisheries conflicts. Lastly, the work is of direct relevance and interest to resource users (e.g., anglers, commercial fishers), who often seek information about management of target species and ecosystems.