MEPS 373:11-23 (2008)  -  DOI: https://doi.org/10.3354/meps07727

ABSTRACT: Several types of design models are currently being used to develop marine protected areas (MPAs) for conservation of coastal and pelagic ecosystems. However, few studies have applied these models in large estuaries which have unique characteristics that need to be considered in MPA design, including strong physical, chemical and biological gradients and significant human impacts. We explored how one design model, MARXAN, can be applied to estuarine systems by developing MPA design scenarios for Long Island Sound, an estuary in the northeastern USA. Using sedimentary texture as a proxy for habitats, we modeled and tested several scenarios where conservation goals differed with respect to location and spatial scale but included 10 to 20% representation of target habitats and spatially contiguous MPAs. When the entire estuary was modeled, potentially critical locations were not included in the solutions. Dividing the estuary into regions to account for spatial gradients proved a better approach. Final MPA solutions were tested for effectiveness by comparing benthic species richness and community composition inside and outside solutions. Solutions in the eastern region of Long Island Sound generally contained higher species richness, likely due to the inclusion of highly heterogeneous portions of the sea floor within most solutions, but community composition varied. In contrast, solutions in the western/central region of the estuary usually had lower species richness but similar community composition. We also made preliminary assessments of how human activities, including dredge disposal, resource extraction and sediment pollution, might affect MPA design in estuaries. Our results illustrate potential conflicts that may arise due to the geographic location of best MPA candidate areas in estuarine regions with environmental impacts and human activities. Several tradeoffs will likely affect MPA design and selection in large estuarine systems, and MPA design models may prove useful in focusing these efforts.

KEY WORDS: Conservation planning · Estuary · Long Island Sound · Macrobenthos · Marine protected areas · MPA · MARXAN · Sea floor landscape