SUCCESSIONAL CHANGES AND DIVERSITY OF SOIL MACROFAUNAL COMMUNITIES ONCHALK GRASSLANDS IN UPPER-NORMANDY (FRANCE)

A study of soil macrofaunal communities was made along a secondary pla nt succession following sheep grazing abandonment in some chalk grassl ands of Upper-Normandy (France). 78 taxonomic units were identified. T axonomic richness was highest in the recently abandoned grassland. Eac h plot was characterised by its own specific taxonomic groups. The env ironmental factors which explained the major contrasts between soil ma crofaunal communities were the extent of tree colonisation and litter characteristics (C:N, biomass). Successional changes induced major cha nges in functional groups of soil macroifauna i.e. endogeic species do minated under herbaceous vegetation while epigeic species were more im portant in woody plots.