FUNCTIONAL CLASSIFICATION OF SOIL FAUNA - A NEW APPROACH

The guild and functional group concepts are generally accepted as suitable units in ecosystem modelling, when interspecific relationships and energy or nutrient flows are studied. It is argued, however, that members of a feeding guild assemblage can have specific effects on ecosystem processes through microstratification, particularly in stratified habitats such as soils. A new concept, 'league', is introduced which follows a guild-like classification, but assembles organisms by their exploitation or processing of more than one habitat resource in a homologous manner. The concept is illustrated for soil fauna feeding habits and choice of microhabitat, and the classification is discussed in view of soil fauna mediated decomposition and nutrient cycling processes. Using literature review data, three leagues are hypothesized for soil fungivores. Epigeic fungus engulfers interact with fungal colonization of fresh leaf litter, with the potential for affecting decomposition rate. Hemiedaphic fungus engulfers affect net mineralization and nutrient mobilization in fragmented litter. Euedaphic fungus engulfers have the potential to affect plant growth by interference with mycorrhizal establishment or nutrient uptake by the roots. Detritivorous soil fauna taxa are also discussed. It is argued that league classification of soil fauna offers a close relationship with individual species impacts on soil processes. Other fields in system ecology are suggested where league classification may be applied.