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FROM MOLECULES TO POPULATIONS: USING POPULATION GENETICS TO ANSWER THE SO WHAT QUESTION
Citation:
BAGLEY, M. FROM MOLECULES TO POPULATIONS: USING POPULATION GENETICS TO ANSWER THE SO WHAT QUESTION. Presented at 2006 Toxicology and Risk Assessment Conference, Cincinnati, OH, April 24 - 26, 2006.
Impact/Purpose:
The objective of this task is to develop molecular indicators to evaluate the integrity and sustainability of aquatic fish, invertebrate, and plant communities (GPRA goal 4.5.2). Specifically, this subtask aims to evaluate methods for the measurement of:
fish and invertebrate community composition, especially for morphologically indistinct (cryptic) species
population genetic structure of aquatic indicator species and its relationship to landscape determinants of population structure (to aid in defining natural assessment units and to allow correlation of population substructure with regional stressor coverages)
genetic diversity within populations of aquatic indicator species, as an indicator of vulnerability to further exposure and as an indicator of cumulative exposure
patterns of temporal change in genetic diversity of aquatic indicator species, as a monitoring tool for establishing long-term population trends.
Description:
Important endpoints for ecological risk assessments are usually those that affect population or species persistence rather than individual-level responses. Nonetheless, ecological risk assessments are generally based on measures of individual-level responses. Extrapolation of individual responses to populations via modeling approaches has received great interest but is limited by data and system understanding; environmental stressors are often multifactorial, with unknown interactive effects among variables, making it difficult to model population responses accurately. Empirical approaches to understanding environmental effects on demographic parameters and population dynamics are helpful but time-consuming and expensive. We have taken the approach of evaluating molecular population genetic patterns in conjunction with environmental variability data to understand population-level responses to changes in environmental condition. Genetic diversity patterns within and among populations result from integrated population responses to various environmental stressors as they impact effective population size, connectivity among populations, and local adaptation. Examples of the population genetic approach will be presented for stream fish populations assessed at the scales of watersheds and ecoregions. Ultimately, we expect our work to contribute to a framework for spatially explicit ecological risk assessment that integrates assessment of landscape stressors and habitat condition with genetic and population modeling approaches.