Impacts of silvicultural practices on the structure of hemi-edaphic macrofauna community

This research determined the influence of six conventional forest management systems on litter-dwelling macrofauna. The forests differed in structure (patch size) and tree composition. Pitfall trapping was carried out in a total of 128 managed stands in the Belgian Ardennes in 1999. We measured the biomass (dry weight) of predators (Arachnida, Carabidae, Staphytinidae and Chilopoda), phytophages (Curculionidae, Homoptera and Elateridae) and detritivores (Lumbricidae, Isopoda and Diplopoda) in young, medium-aged and mature stands in each of the six forest management systems. The major part of the predator biomass consisted of Carabidae in closed-canopy stages and of Arachnida in the regeneration stage. The main phytophagous group trapped was Curculionidae, except in large regenerating stands where Homoptera showed a higher biomass. With respect to forest succession, we obtained higher detritivore biomass in regenerating stands, especially in large ones, higher phytophage biomass in medium-aged stands and higher predator biomass in mature stands. In terms of forest composition, the richest stands as far as biomass and abundance were concerned, were oak forests where predators and detritivores were welt represented, followed by coniferous and mixed forests (phytophages). Beech forests appeared to shelter the lowest abundance and biomass of litter-dwelling macro-invertebrates. This impoverishment is partly due to the less favourable edaphic conditions, but also to the silvicultural practices in these forests. When analysing biomass in terms of forest structure, the size of clear-cut patches was one of the most important features distinguishing even-aged and uneven-aged stands. (c) 2005 Elsevier GmbH. All rights reserved.