Influence of drought and litter age on Collembola communities

A field experiment was carried out to study the impact of drought and litter quality on the structure and performance of collembolan communities, The hypothesis was tested that changes in substrate humidity and resource quality significantly influence decomposition processes via alterations in soil faunal community structure. Litterbags (1000 mum mesh size) containing either freshly fallen or aged spruce litter were placed on the floor of a German spruce forest for one year. The bags were exposed to either ambient conditions (control) or drought (covered with roofs). Drought-induced changes in biological parameters were associated with a strong reduction in decomposition rates. Moreover, drought stress decreased Collembola abundance and species richness. The influence of drought on some microbiological parameters strongly depended on the litter age. A comparison of the two litter treatments revealed major effects of litter age on microbiological and physico-chemical parameters, but no effects on Collembola abundance and species richness. A detailed analysis of the collembolan community structure showed that certain species are highly adapted to specific characteristics of the substrate and thus rapidly respond to changes in microhabitat conditions. (C) 2001 Editions scientifiques et medicales Elsevier SAS.