The objectives of the study were to quantify, compare, and evaluate the levels and distribution of genetic diversity within and among northeast Ohio tributary populations of key darter and unionid mussel species, in relation to anthropogenic habitat fragmentation and habitat quality. These species have historic distributions across Lake Erie and its tributaries, and their genetic divergence patterns and genetic diversities are presently unknown. Our study analyzed historic versus modern factors that regulate their genetic diversity, in effort to conserve it. These populations are being monitored by the Ohio EPA and the Ohio Division of Wildlife, and are anthropogenically sensitive and in decline.

Our concurrent examination of a darter and a mussel species stimulated two research programs that compare diversity across neighboring tributaries of Lake Erie.  Mussels require fish hosts to disperse, and therefore, isolation of fish populations between streams may underlie concurrent variation in populations of freshwater mussels.  The present small grant initiated investigation in this question that has been continued in the laboratories of Carol Stepien at the Lake Erie Center of the Univrsity of Toledo and Bob Krebs at Cleveland State University, and ongoing projects are beginning to elucidate a picture of the variation present in fishes and mussels.  Although the river mouths in northeast Ohio often are close together (<10 miles apart), and each river may support a diverse community of both fishes and mussels, populations from each river can be very different.  As such, protecting the biotas of each of these rivers is necessary as a part of maintaining the watershed of Lake Erie.

The biological problem of species loss and decline is central to interests in environmental change, and the primary rationale of this research project is to develop genetic tools to quantify levels of critical genetic diversity in effort to protect our aquatic fauna. The product of this investigation is a data base quantifying the amount and distribution of genetic variation for key darter and unionid mussel populations in northeast Ohio river ecosystems, along with genetic analyses of their relationships, distribution patterns, and comparative population structures. We are determining whether macroinvertebrates and fishes share a common response to anthropogenic stressors on population fragmentation and decline in habitat quality and quantity. The genetic data bases are being published and made available on our web sites, and the analysis results additionally have been presented at scientific conferences and are being published in scientific journals. The research specifically supplied key genetic data to address three Metrics of the Lake Erie Quality Index (2004), for "Developing a comprehensive inventory of all Lake Erie coastal biological resources", "Continue development of biologically-based assessment tools of the Lake Erie ecosystem", and "Reestablish more natural flow regimes to Lake Erie tributaries". The proposal met the Fishery Research Priorities for the Great Lakes (2003) "Basinwide Priorities" specified by the Great Lakes Fishery Commission (GLFC 2003) for Native Species Rehabilitation, Fish Habitat Assessment, and Development of New Fish Sampling Tools. In addition, freshwater mussels, which are more diverse in the US than anywhere else in the world, are suffering extinction rates higher than any other domestic group of animals. The conservation of our darter and unionid populations is critical for our Lake Erie and tributary ecosystems

We utilized undergraduate student help for the proposed work, whose summer stipends were paid by our National Science Foundation Research Experiences for Undergraduates (REU) summer program (which did not cover the research expenses for these DNA analyses, hence this request). We began the REU program in summer 2003, and collected preliminary data for the proposed work on mtDNA genetic variation in darters and unionid mussels from northeast Ohio Lake Erie tributaries. The samples were collected under our Ohio collecting permits, identified, and tissue-sampled using established protocols. DNA was extracted and purified and the target gene regions were amplified using PCR. Sequence and microsatellite DNA data were collected using our capillary autosequencing facility. Genetic diversity and divergence patterns were statistically compared within and among taxa, and related to the overall species composition of the tributary community, its water and habitat quality, and its anthropogenic disturbance history.