HR: 11:45h
AN: NB22B-06    [Abstracts]
TI: Effects and Non-effects of Stream Drying on Stonefly(Plecoptera) Assemblages in two Ouachita Mountains,AR, Catchments
AU: * Sheldon, A L
EM: andylsheldon@comcast.net
AF: Andrew L. Sheldon, Biological Sciences University of Montana, Missoula, MT 59812 United States
AU: Warren, M L
AF: Melvin L. Warren Jr., USDA Forest Service Southern Research Station, Oxford, MS 38655 United States
AB: Streams integrate landscape change. To establish baseline conditions and predictive relationships in two experimental catchments, we collected adult stoneflies at 38 sites for a year. We used a stratified random sampling design and regular collections of adults, which are identifiable to species level, to ensure thorough coverage. We collected 43 species (1-27 per site). We characterized sites by two descriptors: stream size as drainage AREA, and DRY, a time-weighted average of absence of surface water in measured sections. Sites ranged from continuous surface flow to partial or total drying for months. Species composition (NMS ordination) was influenced strongly by DRY. Richness of species and genera were well described (R2>85%) by multiple regressions on AREA and DRY. However, species richness was related strongly to AREA (P<0.001) but independent of DRY (P>0.45). Generic richness, in contrast, was related significantly(P<0.001)to both descriptors but the negative effect of DRY was stronger. Seasonal drying is common in the Ouachita region and part of the fauna is resistant to drying. Our results have implications for diversity-stress relationships and taxonomic resolution in community ecology and monitoring.
DE: 1812 Drought
DE: 1860 Runoff and streamflow
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly