Plant species effects on soil nematode communities in experimental grasslands

Abstract

We examined the effects of 12 different plant species on soil nematode abundance and community composition, and rotifer abundance, in an experimental grassland in Northern Sweden. Monocultures were grown for six or seven growing seasons before sampling. Four monocultures were grasses, four were legumes and four were non-leguminous forbs. Plant species identity had an effect on the nematode community, both in terms of abundance and composition. The nematode community under Dactylis glomerata was dissimilar to that from the other investigated plant species. Nematode diversity and evenness and the ratio of bacterivores to fungivores plus root-associated nematodes were affected by plant species identity. Generally the greatest abundances of plant-feeding nematodes were found under grasses. Legumes supported large populations of certain bacterial-feeders, especially Rhabditis and Panagrolaimus. The highest numbers of fungal-feeders were found under forbs. However, plant species belonging to the same functional group (grasses, legumes, non-leguminous forbs) had different effects on the nematode fauna. For example, Rumex acetosa had greater numbers of plant-feeding nematodes than the other forbs, and soil under Festuca ovina had greater abundance of bacterial-feeders than soil under the other grasses. Our results therefore suggest that the species of plant is more important than plant functional group for the development of nematode communities.