A Seascape Approach to Understanding Coastal Food Web Dynamics and Species Distributions

Abstract

Seascapes structure, both the amount and configuration of habitats of marine landscapes, have been widely shown to affect production, biodiversity, and species interactions. These are all inherently tied to the food webs in these ecosystems, but less focus has been placed on determining how seascape structure influences food web structure. This dissertation investigates the role of habitats on the distribution of energy, food web structure, and distribution of marine species. This dissertation develops a novel method by combining remote sensing and stable isotope analysis to map the distribution of energy. The energetic landscape, or E-scape, was shown to predict biomass and energy of multiple salt marsh consumers across the seascape. Food web structure was investigated in relation to seascape structure, through seascape characteristics directly or processes that affect seascape structure (disturbance and restoration). Seascape characteristics and disturbance (seagrass die-off) did not affect the mean resource use of consumers, but there were seasonal differences in resource use in both marsh and seagrass ecosystems. The amount of the detrital pathway differed between the seasons resulting in seasonal differences in consumer E-scapes. Restoration had a major effect on resource use in restored food webs, and responses were dependent of the type of restoration performed.