This review (1) describes important regulating forces in
soft-sediment systems, (2) outlines existing models of
community regulation, and (3) revises a model of
community regulation to incorporate soft-sediment systems. The Menge and
Sutherland (MS) model of community regulation and its refinements were
developed for hard-bottom habitats, but can be modified for soft-sediment
systems. This ‘consumer stress model’ posits that mobile consumers
feed ineffectively in harsh environments, and that the relative importance of
physical disturbance, interspecific competition and predation varies
predictably with the magnitude of recruitment, environmental conditions,
productivity and trophic position. The MS model predicts that interspecific
competition for a resource depends directly upon the level of recruitment,
though it does not explicitly address the joint effects of recruitment and
resource availability, which are important in soft-sediment communities. The
model is here revised to incorporate hard-bottom and soft-sediment systems by
changing the recruitment axis to a ‘recruitment:resource ratio’,
whereby the effect of a given level of recruitment depends on resource
availability. The potential utility of the revised model is illustrated in a
hypothetical contrast of the effect of recruitment:resource ratios on
community regulation for a mussel-dominated assemblage in hard-bottom habitats
and an infaunal clam-dominated system in soft sediments.
