Every living thing must have a home. The Chesapeake Bay provides a rich range of habitats for fish, shellfish, eels, birds, and other organisms. Some features of the Bay play very special roles, including underwater grass beds, oyster reefs, and tidal marshes. But even fallen trees and woody debris from forests can serve as habitat for Bay dwellers.
The bottom of the Bay is itself a rich habitat for oysters and clams and for bottom-dwelling fish like gobies, as well as worms, grasses, and other organisms that form the base of the food web.
Habitat can be easily disturbed or degraded, and habitat conservation issues frequently lie at the center of controversy — especially since these important places often serve multiple purposes. Good soft clam habitat, for example, where clam dredgers find their best catches, may also be critical habitat for vulnerable Bay grass beds. Oyster grounds provide watermen with an important seafood resource, but oyster reefs also play a crucial role in the Bay ecosystem, filtering algae and providing a physical home and hiding place for numbers of species. Finding ways to accommodate appropriate uses of Bay habitats while protecting their essential ecological functions presents a significant policy challenge — a balance that requires considerable discussion, communication, and compromise.
In recent years scientists have become especially concerned about another habitat issue: temperature. Temperature has always figured as an important part of an organism’s habitat requirements, but with evidence pointing to a rapid increase in global warming, concerns about temperature have increased (see Global Warming and the Bay). Eelgrass, for example, a dominant species of underwater grass in the lower Bay, lives at the southern end of its range and could be vulnerable to a rise in water temperatures.
Rising temperatures on a global scale will also lead to rising sea levels — a process that has continued since the end of the most recent ice age, about 15,000 years ago. It is that warming process, after all, that melted the glaciers that once covered the northern U.S. and left behind the Great Lakes. Rising sea level also flooded the mouth of the Susquehanna River, creating the estuary that we call the Chesapeake Bay. Sea level rise appears to be accelerating, however, and this rapid rate will likely challenge the adaptive capacity of plants and tidal marshes to keep up. At the same time, development along the shore has made it difficult for marshes to migrate, and put the human landscape, including buildings and roads, at risk.