DIFFERENCES IN SOIL NEMATODE COMMUNITY STRUCTURE OF BEECH FORESTS - COMPARISON BETWEEN A MULL AND A MODER SOIL

The nematode communities of two beech forest soils, a mull soil on lim estone and an acid moder soil, in the same geographic and climatic reg ion were compared. The species composition differed clearly, although the total number of species varied little. Mean nematode density was h igher in moder (2.1x10(6)m(-2)) compared to mull soil (1.3x10(6) m(-2) ). In contrast, mean biomass in mull was significantly larger than in moder. Bacterivorous nematodes dominated in density in mull soil, wher eas root hair feeders dominated in moder soil. Biomass was dominated b y root hair feeders and the fungivorous Tylolaimophorus in moder soil, whereas omnivorous taxa, mainly Aporcelaimellus, dominated mull soil. Density and biomass of c-p groups (sensu Bongers, 1990) differed sign ificantly between mull and moder soil. More 'colonizers' of the c-p 1 group and more 'persisters' of the c-p groups 4 and 5 were present in mull soil. In moder soil a significantly higher density and biomass of the intermediate c-p 3 group occurred. The biomass ratio of Plectidae to Rhabditidae was higher in moder soil than in mull soil. Bacterivor es were assumed to adapt to low bacterial densities in moder soil and to high bacterial densities in mull soil. (C) 1998 Elsevier Science B. V.