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DNA barcodes, species delimitation, and bioassessment: issues of diversity, analysis, and standardization
Citation:
PILGRIM, E., L. M. Boykin, AND B. White. DNA barcodes, species delimitation, and bioassessment: issues of diversity, analysis, and standardization. Presented at Society of Freshwater Science, Louisville, KY, May 20 - 24, 2012.
Impact/Purpose:
The objective is to develop molecular indicators to evaluate the integrity and sustainability of aquatic fish, invertebrate, and plant communities. Specifically, 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:
DNA barcoding has the capability to uncover cryptic diversity otherwise undetectable using morphology alone. For aquatic bioassessment, this opportunity to discover hidden biodiversity presents new data for incorporation into environmental monitoring programs. Unfortunately, the techniques for revealing cryptic taxa vary in their application for analyzing and designating species limits. In order for DNA-based taxonomic methods to be adopted by biological monitoring programs, the methods for delineating cryptic species need to be well understood and end-user friendly. We will present an overview of several analysis techniques for uncovering and delimiting cryptic taxa, including genetic distance measures, reciprocal monophyly, and tip-to-root species delimitation techniques. We will also discuss the utility of these delimitation analyses for verification/refutation of described/disputed species. We then will discuss potential avenues for standardization of these techniques for application to aquatic bioassessment as well as the implications of using this novel biodiversity to assess environmental health.