You are here:
DIATOM SPECIES RICHNESS IN STREAMS OF THE EASTERN US: STREAM SIZE AND HABITAT EFFECTS
Citation:
Hill, B H., S DeCelles, AND M. Vander Borgh. DIATOM SPECIES RICHNESS IN STREAMS OF THE EASTERN US: STREAM SIZE AND HABITAT EFFECTS. Presented at North American Benthological Society, Keystone, CO, May 29-June 2, 2000.
Description:
We analyzed the relationship between benthic diatom assemblages, stream size, and habitat characteristics in 445 first through seventh order streams in the Mid-Atlantic (n=230), South Atlantic (n=61), Ohio (n=140), and Tennessee (n=14) hydrologic regions. Diatom samples were collected from 11 transect locations in each stream and combined to yield a single sample per site. Sampling was done as a part of the USEPA's Environmental Monitoring and Assessment Program (EMAP) surveys in 1997 and 1998. Nearly 600 species of diatoms were collected, though species richness at any one site never exceeded 70. Diatom richness per site was greatest, on average, in streams of the South Atlantic region (40 species), followed by those of the Mid-Atlantic (32 spp.), Ohio (32 spp.), and Tennessee (28 spp.) regions. Stream order was a weak predictor of species richness, accounting for only 3-13% of the variance in the data by hydrologic region. The addition of in situ stream size and habitat measurements improved model r2 to 0.27-0.66. We used canonical correlation analysis to investigate the relationship between species richness and environmental gradients. Richness was significantly correlated with canonical axes representing stream size and in-stream substrate size.