Biodiversity, biogeography, and conservation of freshwater fishes

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Freshwater fishes are among the most imperiled taxa in the world. Over 30% of freshwater fishes in North America, and over 25% in Canada, are of conservation concern. The primary current stressors related to imperilment are habitat alteration and destruction, and aquatic invasive species. While native species are declining, aquatic invasive species (AIS) are spreading in North America. These trends are expected to be exacerbated in the future by stressors such as climate change and human population growth. Biotic homogenization - the increasing similarity of communities across the landscape and the globe - is a result of these trends and is an indicator of biodiversity loss. The objective of my research program is to better understand the patterns, processes, and stressors of Canadian freshwater fishes at multiple taxonomic and geographic scales. Such knowledge is essential for the conservation, protection, and recovery of freshwater fish biodiversity in Canada. Patterns of freshwater fish biodiversity will be examined at the scales of Canada and the Laurentian Great Lakes and their watersheds and tributaries. Overall richness and community patterns will be examined using data from a soon-to-be published national fish atlas, an online Great Lakes fish atlas, and unpublished and newly collected fish distribution data for southern Ontario tributaries. The historical (postglacial history, phylogeny) and environmental processes (abiotic, biotic) that structured those patterns will be identified using a variety of statistical techniques. In addition, the human stressors that currently influence the biodiversity patterns will also be examined. To determine how well Canada’s existing network of protected areas actually protect freshwater fish biodiversity, a gap analysis will be undertaken that overlays biodiversity and protected areas layers. This gap analysis will identify fish species and communities in need of additional protection. To elucidate the underlying mechanisms of interactions between native freshwater fishes and fish AIS, their history of co-occurrence in the Great Lakes will be examined. Based on recently published book chapters, species lists for each Great Lake will be reconstructed by decade from pre-1870 to 2010 and used to examine the history of native species loss and AIS invasion. This will facilitate testing of many of the hypotheses related to the establishment and impact of AIS (e.g. biotic resistance, niche overlap). These hypotheses will be tested through multivariate analyses of ecological and life-history traits to examine trait space changes over time. The proposed research includes several novel components. Analyses that examine the influence of history, environment, phylogeny, and stressors on freshwater fishes have not been conducted comprehensively for Canada or the Great Lakes. Gap analyses to evaluate how well freshwater fishes are protected by protected areas have not been published for Canada or the Great Lakes. The decadal Great Lakes database provides a unique opportunity to test invasion theory hypotheses and species homogenization over an extended time periods.