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ASSESSING THE HYDROGEOLOGIC CLASSIFICATION SYSTEM IN MID-ATLANTIC COASTAL PLAIN STREAMS USING BENTHIC MACROINVERTEBRATES
Citation:
Hutchens, J J., K A. Blocksom, D J. Klemm, S. W. Ator, J. M. Denver, A M. Pitchford, AND M H. Mehaffey. ASSESSING THE HYDROGEOLOGIC CLASSIFICATION SYSTEM IN MID-ATLANTIC COASTAL PLAIN STREAMS USING BENTHIC MACROINVERTEBRATES. Presented at North American Benthological Society, Pittsburgh, PA, May 28-June 1, 2002.
Impact/Purpose:
The purpose of this research project is to provide methods, tools and guidance to Regions, States and Tribes to support the TMDL program. This research will investigate new measurement methods and models to link stressors to biological responses and will use existing data and knowledge to develop strategies to determine the causes of biological impairment in rivers and streams. Research will be performed across multiple spatial scales, site, subwatershed, watershed, basin, ecoregion and regional/state.
Description:
Assessing classification systems that describe natural variation across regions is an important first step for developing indicators. We evaluated a hydrogeologic framework for first order streams in the mid-Atlantic Coastal Plain as part of the LIPS-MACS (Landscape Indicators for Mid-Atlantic Coastal Streams) project being conducted jointly by USEPA and USGS. A network of 174 sites was chosen across seven hydrogeologic regions usng a stratified random sampling approach with unequal selection probabilities so that sites corresponded to a developed (i.e., agriculture and urban) land use gradient within each region. We examined whether macroinvertebrate assemblage structure in 33 reference streams corresponded to variation described by the regions. Assemblage structure did not match well with the hydrogeologic system based on ordination using non-metric multidimensional scaling. Furthermore, assemblage structure did not significantly differ (p=0.513) among regions using a multi-response permutation procedure, although two regions were excluded due to low sample size. Instead, ordination and cluster analysis revealed three groupings that appeared to be tied to physical habitat and chemical buffering capacity. Although more reference sites in some regions would increase our confidence, these results suggest that macroinvertebrate indicators can be developed for first order Coastal Plain streams without stratification by hydrogeologic region.