Incorporation of soft-sediment systems into a model of marine benthic community regulation

Abstract

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.