NEMATODES IN A COASTAL DUNE SUCCESSION - INDICATORS OF SOIL PROPERTIES

The nematode fauna of coastal sand dunes in the Slowinski National Par k (Poland) were studied. Within the wet parts of dune hollows, vegetat ional succession starts from bare wet sand gradually colonized by gras ses and mosses, and changes to plant communities dominated by sundew a nd heath. The aim of the study was to determine whether vegetation suc cession was accompanied by a parallel succession of the nematode fauna . Samples were taken from 12 subsequent stages of vegetational success ion. The extracted nematodes were determined up to genus level after B ongers (1987). The percentage of nematodes of different feeding types (bacteriophagous, fungivorous, predators, plant-parasitic and omnivoro us) was calculated for every site. Soil moisture (average water table and actual water content), the existence of an upper organic soil laye r and pH seem to be the key environmental factors influencing nematode community structure. Multivariate analysis techniques were used to cl assify the nematode samples into four groups: A - the nematode communi ty in sites at early succession stages without permanent colonization by plants. B - the nematode community in sites at stages with permanen t plant cover (grasses and higher plants). C and D - the nematode comm unities in sites with a developing permanent and stable soil organic l ayer, but differing in water regime. Changes in the incidence of nemat odes of different feeding types in relation to vegetational succession support this classification. Nematode community structure changed fro m a high percentage of predators to a dominance of bacterial feeders. Fungal feeding nematodes only occur in abundance in sites with a devel oped organic layer and higher moisture content (group D), and the nema tode community may be a good indicator of the progress of ecological s uccession in the deflation hollows. (C) 1998 Elsevier Science B.V.