Mangrove Swamps

Black Mangrove (Avicennia germinans) is the most common mangrove in the United States outside of the everglades. The straw-like spikes surrounding this plant are pneumatophores.

Mangrove trees dominate this wetland ecosystem due to their ability to survive in both salt and fresh water. In the continental United States, only three species of mangrove grow: red, black, and white mangroves. Red Mangrove (Rhizophera mangle) is easily recognized by its distinctive arching roots. Black Mangrove (Avicennia sp.), which often grows more inland, has root projections called pneumatophores, which help to supply the plant with air in submerged soils. White Mangroves (Laguncularia racemosa) often grow even farther inland with no outstanding root structures.

A wide diversity of animals is found in mangrove swamps. Since these estuarine swamps are constantly replenished with nutrients transported by fresh water runoff from the land and flushed by the ebb and flow of the tides, they support a bursting population of bacteria and other decomposers and filter feeders. These ecosystems sustain billions of worms, protozoa, barnacles (Balanus spp.), oysters (Crassostrea spp.), and other invertebrates. These organisms in turn feed fish and shrimp, which support wading birds, pelicans, and the endangered Crocodile.

Functions & Values
The importance of mangrove swamps has been well established. They function as nurseries for shrimp and recreational fisheries, exporters of organic matter to adjacent coastal food chains, and enormous sources of valuable nutrients. Their physical stability helps to prevent shoreline erosion, shielding inland areas from severe damage during hurricanes and tidal waves.

Status
As these wetlands are increasingly threatened by the damming of upstream sources, significant decline in their integrity and productivity has been observed. Mangrove swamps have experienced loss of 3.2 percent since the 1950s. However, efforts are underway to enhance the protection of these valuable ecosystems.