Date of Award





Earth and Space Science - Environmental Science Track


Earth & Space Science

First Advisor

James A. Gore


The Georgia Ecoregions Reference Sites Project has developed biological criteria for streams in Georgia according to the Rapid Bioassessment Protocols For Wadeable Streams and Rivers. Streams will ultimately be classified into categories of impairment so that management decisions can be made in accordance with the Clean Water Act. A cost-effective approach to accomplish mandates set forth by the Clean Water Act must be employed, as state budgets are limited. One means of examining costs is to assess taxonomic resolution. Taxonomic resolution not only assesses the sensitivity of biocriteria, it also allows one to make recommendations to state agencies regarding the costs and benefits of recommended taxonomic identification requirements. Due to the broad diversity in geology, topography, climate, soils and geography within Georgia, taxonomic resolution requirements may vary. Thirty macroinvertebrate samples from five reference condition streams and five or six impaired streams from three Georgia sub-ecoregions were identified to "lowest possible" or lowest practical level. Lowest practical level includes many taxonomic levels determined by the group identified and the availability of peer-reviewed keys. Specific data from lowest practical level were reduced to generic level then further reduced to familial level so that three identification levels, incorporated into sub-ecoregional specific invertebrate indices, were assessed for discriminatory ability. Time spent on identification was recorded at each taxonomic level so that identification "costs" versus "benefits" or degree of information could be used in conjunction with the indices in determining recommended taxonomic resolution requirements. Final analysis indicated taxonomic resolution requirements vary among subecoregions within Georgia and future benthic work, at least in some subecoregions, will require less time and money. By performing cost/benefit analyses, agencies involved in bioassessment and biomontioring programs can identify regions that may require less taxonomic effort.