Effects of Water Transported Sediment on Corticolous Lichen Communities

Abstract

AbstractThe spatial distribution of corticolous lichens was studied along Big Seven Mile Creek (Cabell County, West Virginia, U.S.A.), a small stream that was periodically inundated by floodwaters carrying heavy loads of sediment. Lichen communities located at 0, 1.0 and 1.5 km from the confluence with the Ohio River were compared using step-wise discriminant analysis, a multivariate technique. Of the physical factors tested, the results indicated that the sediment on the tree boles was the most important factor separating the three stations and bole heights. Species richness was established to be an important mensurational variable separating stations, bole heights, and parallel and perpendicular transects. Changes observed in lichen community structure are assumed to have resulted from microclimatic variation brought about primarily by sedimentation associated with flooding. Failure of the physical factors and biotic variables to separate tree bole aspects (faces of boles in respect to the stream) indicate that abrasion and current-induced exfoliation are not important factors affecting lichen communities in the study area. Corticolous lichens occurring along streams subject to periodic inundation may represent a useful indicator in studies of flooding, water quality, and/or sedimentation in watersheds.