Summary AimThe community composition of benthic macroinvertebrates from 295 estuarine sites was examined in order to either confirm or challenge established boundaries of zoogeographical provinces. We also investigated the postulate that, while local distributions were determined by natural habitat characteristics such as salinity, sediment type and depth, distributions on a large geographical scale would be correlated with temperature. LocationThe Atlantic coast of the United States (on a latitudinal gradient from 42° to 25°N). MethodsUsing the descriptive techniques of cluster analysis and nonmetric multi‐dimensional scaling, we determined the similarities in benthic community composition between sites within 1° latitudinal bands and compared the biotic ordinations to natural habitat characteristics such as salinity, sediment type and depth. We then evaluated the overall community composition within each 1° latitudinal band and established whether or not similarities existed between adjacent 1° latitudinal bands. In this manner, we were able to confirm that a latitudinal gradient existed in estuarine benthic community composition along the western Atlantic coast. This latitudinal gradient was demarcated by biogeographical boundaries at (1) Biscayne Bay, Florida, (2) the southern end of the Indian River Lagoon, Florida, (3) St John's River, Florida, (4) Cape Island, South Carolina, (5) the mouth of the Cape Fear River, North Carolina and (6) Cape Cod, Massachusetts, with a subprovince boundary just north of Cape May at Wildwood, New Jersey. ResultsThe major divisions approximated widely recognized biogeographical boundaries. Average summer water temperatures correlated better than sediment type, depth, or salinity with the latitudinal groupings of sites determined by cluster analysis. ConclusionsBased on this relationship, we speculate on the potential impacts of current global climate change scenarios on the distribution of benthic macroinvertebrates along the western Atlantic coast.

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Gulf of Mexico (GOM) coastal wetlands contribute to human well-being by providing many ecosystem services. The GOM region continues to experience substantial losses of coastal wetlands, but the magnitude of reduction in ecosystem services resulting from the loss of GOM coastal wetlands is unknown. To gain an appreciation of the impact of GOM coastal wetland loss on ecosystem services, recent literature was reviewed to derive quantitative estimates of ecosystem services provided by GOM coastal wetlands. GOM coastal wetlands provide essential habitat for the production of juvenile shrimp, which supports the GOM's most valuable commercial fishery; protect coastal communities from storm surge; improve water quality by removing nitrogen from surface waters; and are valuable sinks for greenhouse gases due to high rates of carbon sequestration combined with low rates of methane emission. Using 1998 to 2004 as a baseline, the potential loss of ecosystem services associated with loss of coastal wetlands is presented. Additional research is needed to quantify wetland services at multiple geospatial and socioeconomic scales, to determine the effect of wetland loss on ecosystem services, and to demonstrate the impact of future management decisions on the capacity of GOM coastal wetlands to provide services that affect human well-being.

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