| |
Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Bioassessment
ASSESSING A HYDROGEOLOGIC CLASSIFICATION SYSTEM IN MID-ATLANTIC COASTAL PLAIN STREAMS USING BENTHIC MACROINVERTEBRATES.
J.J. Hutchens1, K.A. Blocksom1, D.J. Klemm1, S.W. Ator2, J.M. Denver3, A.M. Pitchford4, and M.H. Mehaffey4. 1Ecosystems Research Branch, National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, OH 45268, 2US Geologic Survey, Baltimore, MD 21237, 3US Geologic Survey, Dover, DE 19901, 4Landscape Ecology Branch, National Exposure Research Laboratory, US Environmental Protection Agency, Las Vegas, NV 89193
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 using 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
|
|
