EFFECTS OF PLANTS ON NEMATODE COMMUNITY STRUCTURE.

Plant-related inputs provide the resources for nematode communities. Sampling of nematode communities must be on appropriate temporal and spatial scales. Size, feeding types, food or host specificity, and chronology allow over 200 nematode species to coexist in a district. Relationships between nematode functional groups and ecological processes regulating decomposition processes have been found in field experiments. Pulse-labeling experiments have shown root-feeding nematodes to increase the flow of carbon from roots to soil microbial biomass. Soil texture is related to suitability for cropping and affects nematode communities through crop-specific infestations. Nematode diversity tends to be greatest in ecosystems with least disturbance, and bacterial-feeding nematodes make the greatest contribution to the decomposer food web in more intensively managed ecosystems. Indices of the nematode fauna reflect changes in the nematode community; these changes reflect soil and ecological processes. Understanding the role of nematodes in these processes is the key to understanding of the relationship between plants and soil nematode communities.