In this way, the relative risk to many species of waterbirds can be assessed over both short and long terms. In some areas, such as Louisiana and in the middle parts of the Chesapeake Bay in Maryland, little question remains that sea level rise and subsidence are causing rapid reversion of marsh to open water. Marsh accretion simply is insufficient to keep up. Thus, in 100 years, lagoonal marshes will experience a net elevational loss of about 20 cm. I also restrict my scenario to the endpoint of the 100 years, not the intervening periods with gradual changes in area and microhabitat shifts.
White areas are regions of no net change.
The coastal marshes of the mid-Atlantic are an extremely important habitat for many species of wildlife. Population sizes can often be immense - in winter, one species alone, the Greater Snow Goose may exceed 100,000 individuals among southern New Jersey, Delaware, and Maryland. Waterfowl totals in winter from New Jersey south to Virginia often exceed one-quarter million birds. Colonially nesting species such as Laughing Gulls often exceed 120,000 individuals, mostly in New Jersey and Virginia, where colonies sometimes reach 5000 individuals. Norway rats, all major predators on bird nests.