Abstract for presentation at Biodiversity Extinction Crisis Conference - A Pacific Response

Marine soft sediment habitats contribute substantially to primary productivity and ecosystem function. These seascapes are composed of complex, heterogeneous communities, often created from biogenic structure. Both natural and anthropogenic disturbances impact these habitats, with the potential to result in habitat fragmentation and long term degradative change. We model a mosaic of patches to illustrate how disturbance and habitat structure interact to determine recovery of these biogenic habitats. We simulate three typical marine benthic communities with differing life history characteristics. We vary the spatial extent and frequency of disturbance events which reduce the community to a pioneer state, assuming that communities age through a series of successional stages toward a mature community. The relative importance of habitat structure is demonstrated by allowing colonisation of disturbed habitats only if patches are within a certain dispersal distance from a patch containing structured habitat. The model indicates functional extinction of mature community stages under many combinations of temporal and spatial frequencies of disturbance. The range of feasible combinations of disturbance decreased as the size of the colonist neighborhood decreased, and for longer-lived communities. Our results demonstrate that rates corresponding to common anthropogenic disturbances are not sustainable for typical marine soft sediment communities, and emphasise the value of habitat-forming species for preserving marine ecosystems in the face of increasing rates of anthropogenic disturbance.