Substratum-production relationships in net-spinning caddisflies (Trichoptera) in disturbed and undisturbed hardwood catchments.

The effect of substratum on production of two species of net-spinning Trichoptera was examined in two second-order Southern Appalachian streams: Hugh White Creek, a reference stream draining an undisturbed hardwood catchment, and Big Hurricane Branch, which drains a catchment that was clear cut during the first six months of the study. Surber samples were collected monthly for 21 months in four common substrata in each stream: moss-covered rock face, cobble riffle, pebble riffle, and sandy reach. Both species showed distinct substratum preferences. Abundances and production were significantly higher in rock face > cobble riffle > pebble riffle > sandy reach in both streams. Differences in production between streams may be related more to geomorphic differences between streams than to effects of logging on these two species.