The structure and function of food webs in soil

Several soil food webs have been thoroughly described and the importance of nematodes is evident from their representation at different trophic links - as plant-feeders, secondary detritivores, predators and omnivores. Carbon flow models have shown the importance of several pathways, including those through bacterial- and fungal-feeders to predaceous nematodes, and from plant roots through plant-feeders. The herbivory pathway has been observed experimentally by following a pulse of C-13, applied above-ground, through the soil community. Novel observations are also emerging on the effects of root-feeding fauna on above-ground food webs. Disturbance of food web groups causes a loss in stability, reduced biodiversity and changes in soil processes. Consideration of biodiversity in food web models will allow exploration of biodiversity-productivity and biodiversity-stability relationships. Modelling interactions according to function rather than species reveal interesting interactions in above-ground food webs. Current soil food web models group organisms by function and taxa, but for improved understanding of the system information on broader functional groups may be more appropriate. Current initiatives and developments in food web research and theory highlight the importance of soil food webs in biosphere function and are providing insights into the preservation, conservation and management of soil systems.