Life-Stage-Based Recovery Dynamics of Marine Invertebrates in Soft-Sediment Habitats

Abstract

Marine soft-sediment habitats are the most common on earth (Snelgrove et al. 1997) and have important conservation and intrinsic values that make them important to study. For instance, these habitats can have extraordinarily high biodiversity (Gray et al. 1997), can play important roles in supplying food for fish and humans, and can influence global carbon and geo-chemical cycling (Graf 1992). In addition, soft-sediment habitats, particularly those situated in coastal regions of the world, are frequently subjected to a wide array of human disturbances and consequently bottom-dwelling invertebrates have become important indicators of environmental effects (Gray 1981). Human impacts on these habitats can be both chronic and acute and can range over a variety of temporal and spatial scales (Zajac et al. 1998). These impacts frequently result in impaired community function and structure (Gray 1997, for a recent review). For example, the dragging of mobile fishing gear across the seabed often destroys the complex biological structures and vertical relief provided by sessile epifaunal invertebrate communities (Auster and Langton 1999). In addition to the direct reduction in adult fish stocks, such practices can potentially decrease the survival of juvenile fish and other mobile fauna by reducing prey refuges and increasing predator strike efficiency (Lindholm et al. 1999). Infaunal invertebrates are also capable of producing biogenic structures and are an important food source for a multitude of species. Despite the importance of invertebrates in soft-sediment habitats and their susceptibility to human impacts, considerable information is needed before we can accurately assess and predict how soft-sediment populations and communities respond to human-induced perturbations.

When we observe the environment, we necessarily do so on only a limited range of scales; therefore, our perception of events provides us with only a low-dimensional slice through a high dimensional cake. Simon A. Levin, The Robert H. MacArthur Award Lecture 1989 (manuscript published in 1992 [Ecology 73(6): 1943–1967])