Disturbance-Recovery Processes and Patterns In Benthic Habitats

Studies of modern benthic communities generally focus on using a combination of organism life history and functional group traits to assess disturbance-recovery patterns in benthic habitats. Typically the early stages of community recovery following a disturbance are dominated by small “opportunistic” or “pioneer” species which are often tube-dwelling and feed on surface sediments. These species often have life-history traits (e.g., high reproductive capacity, good dispersal potential) that facilitate rapid responses and large increases in population abundance to recently disturbed areas. As the recovery process proceeds, the opportunists are often replaced by larger, deeper-dwelling forms (e.g., “climax" species) which bioturbate the sediments and increase the depth of the oxygenated layer in the sediment column. These late successional stage species have longer life spans and slower population growth rates. A variety of studies, particularly those derived from small-scale disturbance-recovery experiments, have shown the disturbance-recovery pattern described previously can vary with habitat conditions, demographic characteristics of the colonist pool and seasonal differences in species in colonist availability. In addition, there is increasing evidence that the successional process can influenced by the intensity or spatial extent of disturbance. For example, the time for a community to recover from a disturbance tends to be correlated with the spatial scale of disturbance. Scale-dependent opportunistic responses appear to be driven by habitat and hydrodynamic conditions coupled with species' life history characteristics. In benthic communities there frequently is a relationship between biodiversity and ecosystem functioning (e.g., production, mineralization of organic matter, nutrient regeneration). Thus, the gradual replacement of species in the successional process is accompanied by changes in ecosystem functioning. Such changes are likely particularly important following large-scale disturbances.