The influence of land use systems on substrate patterns in brooks and their benthic macroinvertebrate microdistribution

From 1994 to 1996, field experiments were conducted in two small brooks situated at the Research Station Scheyern of the FAM Research Network on Agroecosystems, in order to analyze substrate patterns and macroinvertebrate microdistribution, and the feeding type distribution of macroinvertebrate coenoses. Substrate patterns in brook sections adjacent to forests and to agricultural land differ. The structure (species and their abundance) of macroinvertebrate coenoses differed only between communities on organic and inorganic substrate types, and were independent from their sampling situation in the brooks. On a population level, distinct substrate preferences of different taxa were observed, whereby organic substrates were most significantly preferred. The feeding type reophileous shredder prevailed in most macroinvertebrate coenoses, as Gammarus pulex L. (Amphipoda) was the eudominant species. Due to this dominance, the coenoses were characterized as typical of tertiary hill land brooks, in respect to the food and current preferences of their species.