NEMATODE DISTRIBUTION, TROPHIC STRUCTURE AND BIOMASS IN A PRIMARY SUCCESSION OF BLOWN-OUT AREAS IN A DRIFT SAND LANDSCAPE

The nematode fauna of a successional sere in a blown-out area in a dri ft sand landscape, including drift sands without vegetation, Spergulo- Corynephoretum and Scots pine (Pinus sylvestris L.) forests of differe nt ages, was studied. Samples were taken from the 0-10 cm mineral soil and, in the forested stages, also from the organic layers. The organi c layers were divided into litter, fermentation and humus horizons. Th e initial stages of succession were dominated by omnivorous nematodes. Nematodes feeding on lower plants were restricted to the surface laye rs and different species occurred during the succession. In litter hor izons nematode trophic structure followed microfloral succession. The occurrence of plant feeding nematodes could be related to rooting patt erns of herb and tree species. Bacterial and plant feeding nematodes r eached highest densities and biomass m(-2) in the fermentation horizon s and increased during succession. Predatory nematodes were rare and o ccurred only in mineral soil. Average nematode length differed by soil horizon and decreased in the 0-10 cm mineral soil during succession. Relations between nematode morphometrics and micro-climatological cond itions are discussed.