EFFECTS OF SPRUCE PLANTATIONS ON CARABID BEETLES IN SOUTHERN BELGIUM

(1) During 1989 and 1990, carabid beetles were collected monthly in 11 spruce plantations of increasing age. The total sample includes 3997 individuals belonging to 50 species. (2) Most colonizing species were either generalist species, well-fitted to colonization, or forest spec ies. (3) Age of the plantation affects both the species composition an d richness of the carabid communities. These variations are correlated with changes in both structural and vegetational characteristics of t he plantations. (4) A strong heterogeneity between carabid communities occurring in young plantations was detected. This heterogeneity seems to depend on local ecological conditions. (5) Comparisons between car abid communities of spruce plantations and those of other regional hab itats show that carabid species from the regional pool take advantage of the availability of a new habitat to build populations. (6) On a re gional scale, spruce forestry acts as a patch dynamics system of distu rbance. The importance of the exchange between the pieces of the regio nal mosaic of habitats is outlined.