Osprey, like this one near Long Island, New York, depend on still or slow-moving waters, including lakes, estuaries, and coastal wetlands, for the fish and other creatures they eat. Vicki Jauron/Getty Images

Although coastal habitats make up only a little more than 3 percent of the United States’ marine territory (about 146,000 square miles), they have an outsized positive impact, encompassing highly productive areas essential to ocean life health.

These habitats, however, are under increasing threat: Pollution, poorly planned development, sea-level rise, and other factors have led to degradation. Examples include:

Kelp forests—home to more than 1,000 species—have been reduced to an all-time low along the U.S. west coast.

Oyster reefs—which improve water quality, provide habitat for marine life, and provide a popular food for people—have declined up to 90 percent since the late 1880s because of a combination of pollution, disease, and overharvesting.

Rocky habitats—which provide shelter and food for more than 1 million seabirds—are increasingly vulnerable to sea-level rise, coastal development, and other threats.

Salt marshes—which provide breeding areas and nurseries for fish, invertebrates, and shorebirds—have declined significantly in both size and number throughout the U.S.

Seagrass beds—which filter water, reduce erosion, and support marine habitat—are disappearing at a rate of two football fields an hour.

Pew works with national, state, and local officials, scientists, and others to secure formal protections and management plans that are vital to conserving these important areas.