Short-term responses of soil decomposer communities to forest management: clear felling versus alternative forest harvesting methods

We studied the short-term responses of decomposers to different forest harv esting methods in a boreal spruce forest (Picea abies (L.) Karst.). We hypo thesised that the less intensive the forest harvesting method is, the fewer changes occur in the decomposer community. The treatments, in addition to untreated controls, were (1) selection felling (30% of the stand volume rem oved), (2) retention felling (tree patches retained), (3) clear felling, (4 ) gap felling without and (5) with harrowing. Microbial community structure (phospholipid fatty acids (PLFA) pattern) changed in the first year, micro bial biomass and basal respiration decreased in the second year, and densit y of the enchytraeid worm Cognettia sphagnetorum (Vejd.) increased in the t hird year after the clear felling. The community of collembolans did not re spond to forest harvestings. Although there were changes in the microbial c ommunity, the invertebrates at higher trophic levels did not parallelly res pond to these changes. The selection felling had no influence on the decomp osers, while the gap fellings induced an increase in the numbers of enchytr aeids in harvested gaps. We conclude that the decomposers of the coniferous forest soils are well buffered against initial environmental changes resul ting from forest harvesting, and also that the PLFA pattern is a sensitive indicator of changes in the microbial community induced by forest harvestin g.