Genetic Diversity of Fish and Invertebrates as Indicators of Ecological Condition

This research aims to evaluate the utility of population genetic measurements for deriving important population parameters of populations exposed to anthropogenic stressors. A primary focus of this research is the molecular characterization of genetic diversity, a fundamental component of biodiversity. Genetic methodologies will be used to help characterize:

• appropriate ecological units (biological populations) for assessment of fish communities
• species differences for morphologically indistinct or cryptic taxa
• the inherent vulnerability of aquatic species to further exposure to stressors
• the relationship between genetic diversity and environmental condition
• temporal trends in the condition of fish, plant and invertebrate populations
• linkages between landscape-level stressors and population-level outcomes for aquatic organisms

By identifying the spatial scale at which individuals migrate and breed, measures of genetic diversity define biological populations, which are the most meaningful ecological units for assessing species communities. A significant loss of genetic diversity is detrimental to populations and affects their sustainability into the future. In the short term, reduced genetic diversity can contribute to inbreeding depression, lowering population fitness.  In the long term, it reduces the population's resilience because the population's genetic pool of potential responses to stress is restricted. The population's lack of selectively propitious genes may lead to further population declines and eventual extirpation when faced with novel stressors or changes in stressor intensity. In addition, since past and present environments have shaped current levels of genetic diversity, molecular genetic markers are natural indicators of cumulative population exposure. Degradation of habitat (chemical, physical, or biological), hybridization with introduced taxa, and habitat fragmentation have predictable effects on genetic diversity. Coupling of these molecular genetic data with quantitative environmental data and landscape data gathered through EMAP and other initiatives will allow powerful inferences to ecological condition and population responses to environmental stressors.

To develop and employ molecular genetic methodologies for assessment of the condition, biological integrity, and sustainability of aquatic fish, invertebrate, and plant communities.

• Regional patterns of genetic diversity in stream fishes of the eastern United States
• Landscape Genetics of the Great and Little Miami Watersheds
• Adaptive Responses of Upland Coastal Marsh Plant Communities to Climate Change
• Genetic Diversity: An Indicator of Ecological Condition and Sustainability
• Targeted Screening for Invasive Species in Ballast
• Historical Trends in Tissue Contamination and Genetic Diversity within the Tahoe Basin