Combined effects of water chemistry, canopy cover, and stream size on benthic macroinvertebrates along a Central Appalachian stream continuum

I sampled benthic macroinvertebrates along a 25.2 km stream continuum in the Central Appalachian Mountains of West Virginia from May---October 2000. Six components of macroinvertebrate community structure and function were measured: density, biomass, richness, community taxa similarity, feeding group composition, and metric composition. I quantified these components to determine if localized variation in alkalinity and canopy cover would modify stream continuum predictions. Localized variation in alkalinity and canopy cover significantly affected macroinvertebrate structure and function and modified stream continuum predictions. Results indicated that alkalinity was the primary determinant of macroinvertebrate structure and function, and that the effects of canopy cover and stream size were secondary and tertiary determinants, respectively. Evaluation of these findings suggests that small-scale variation in the geology and riparian character of Central Appalachian watersheds can modify stream continuum predictions at a continuum-specific level