Impacts of Sea Level Rise on Marsh as Fish Habitat

Abstract

Sea level rise and accompanying coastal squeeze will drive changes in marsh spatial configuration and connectivity affecting how fishes utilize the marsh. We investigate how sea level rise and coastal squeeze affect the spatial distribution, configuration, and connectivity within tidal marshes in a landscape context. Using spatial analyses, we compare two outputs from a process model: one with constant vertical accretion and the other with a more optimistic prediction that rates of vertical accretion will equal rates of sea level rise. We use landscape metrics on the model outputs to evaluate the landscape scale changes that occur in a selected marsh at the National Estuarine Research Reserve (NERR) site in Wells, Maine, USA. We found that moderate sea level rise would benefit marshes by expanding their area and maintaining habitat spatial complexity. However, rapid sea level coupled with stressors like coastal squeeze is likely to result in smaller and more dispersed marshes with simpler patch edges and less connected patches. Such features indicate lesser potential for food and refugia.