HR: 09:15h
AN: NB51F-04    [Abstracts]
TI: The Effect of Subsampling Effort on Macroinvertebrate Community Variables in Streams of the Interior Highlands (Arkansas, USA)
AU: * McCord, S B
EM: smccord@astate.edu
AF: Environmental Sciences Program, Arkansas State University, P.O. Box 847, State University, AR 72467 United States
AU: Grippo, R S
EM: rgrippo@astate.edu
AF: Environmental Sciences Program, Arkansas State University, P.O. Box 847, State University, AR 72467 United States
AB: Bioassessment of stream invertebrate assemblages is increasingly used to assess the effectiveness of silvicultural best management practices. An important challenge in these studies is determining the size of a subsample that is representative of the assemblage, but remains time- and cost-effective. We examined community characteristics calculated from 100- and 300-organism subsamples of 90 benthic invertebrate samples, to determine whether the larger subsamples provided enhanced ability to discriminate between seasons and ecoregions. Samples were collected from five streams in two ecoregions during two seasons. Total richness and EPT richness were consistently greater in the larger subsamples in both winter and spring for each study stream. However, fourteen community characteristics that were based on relative abundances of various groups rarely differed significantly between 100- and 300-organism subsamples. Seasonal variation in all characteristics was equally evident in subsamples of both sizes. Similarly, differences in assemblage characteristics between ecoregions were as evident in the smaller subsamples as the larger ones. Our results did not indicate that the larger subsamples enhanced the ability to discriminate between samples taken from different seasons, or from unimpaired streams of these two ecoregions.
DE: 9902 NABS Student Award Applied Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly