COLONIZATION OF BROWN AND BLEACHED LITTER OF A BEECH FOREST BY EDAPHIC MACROARTHROPODS

From January to June 1988, experimental field work utilizing the litte r bag technique was carried out in the biological reserve of La Tillai e (Fontainebleau Forest, France). The aim was to study the relationshi ps between the qualitative characteristics of beech litter - especiall y the bleaching degree by white-rot fungi (Basidiomycetes) - and its c olonization by edaphic macroarthropods. Five groups were particularly studied: the isopods, dipterous larvae of families Chironomidae, Cecid omyiidae and Scatopsidae, and predators. Though all the groups were al ways present in both types of litter (brown and bleached), significant differences were observed concerning the isopods, the cecidomyiid lar vae and the predators which were more abundant in brown leaves, and th e scatopsid larvae which were most abundant in the bleached leaves. Th e dipterous larvae were more abundant in winter, whereas the isopods a nd predators were more abundant during the spring and early summer. Th e colonization of the two types of litter took place during periods wh en the different groups reached their maximum densities. Chironomid la rvae seem to be indifferent to the state of the litter.