Abstract
- A number of functional-group hypotheses have been proposed to explain the occurrence of distinct faunal assemblages in benthic communities. However, the generality of such interactions is uncertain. The predictions of a mobility-mode functional-group hypothesis are here compared with experimental studies in order to determine its usefulness as a model for community interactions. This hypothesis appears to provide a good predictive framework under limited conditions. Dense aggregations of large organisms or those with strong sedimentary effects may exclude smaller species through modifications related to their mobility type. However, the interactions are asymmetrical. Dense assemblages of smaller species have not been shown to exclude larger forms. These results suggest a re-evaluation of the conditions necessary for mobility-related interactions to become important in regulating the composition of a benthic community. Although the mobility-mode theory describes the influence of active or large members of a tideflat community, care should be taken in assuming such interactions among smaller fauna.