Cover

CHAPTER IV: WILDLIFE HABITATS FOR MISSISSIPPI’S SGCN,

THREATS AND CONSERVATION ACTIONS^242

Rivers. Their substrates are muddy in texture because they originate from the eroding intertidal
marshes, where the shoreline retreats several feet every year. However, a few significant segments of
sand or shell beach exist along the mainland, such as along the Rigolets Islands. The Rigolets are a
group of small marshy islands occurring on the borders of Mississippi and Alabama. Additional sand
beaches are found at Point aux Chenes, southwest of the mouth of Graveline Bayou, southeast of the
mouth Davis Bayou in Jackson County, on Big Island in Back Bay of Biloxi in Harrison County and
between the mouth of Bayou Caddy and Landmark Bayou in Hancock County. A few smaller beaches
occur in other areas. These coarse-textured beaches are very important nesting areas for the Mississippi
diamondback terrapin.

In addition to beaches of the larger coastal water bodies, mud and sandy mud shores line the tidal
streams of the coastal estuaries. These shorelines have similar ecological functions as mud flats. Mud
shores harbor numerous microorganisms such as phytoplankton, fungi, bacteria and protozoans that
serve as an important food source for benthic invertebrates (polychaetes, mollusks and crustaceans),
which in turn support mid and upper level consumers such as crabs, shorebirds, shrimp and fish.
Wading and shorebirds are especially dependent on mud shores. Herons, egrets, sandpipers, plovers,
godwits, willets, terns, gulls, ducks and osprey frequent this habitat.

A component of beach habitats in Mississippi are ephemeral habitats or "bryozoans"-floating colonies.
These are seasonally important and provide structural habitat and nutrient and carbon sources that are
used by invertebrates, fishes and wading birds.

LOCATION, SIZE, CONDITION AND CONSERVATION STATUS
NGM

Mainland beaches are narrow linear intertidal areas that extend
along bayous, bays and tidal rivers. They form the interface
between subtidal areas and intertidal marshes and occasionally
directly adjoin uplands. On average, mud flats and muddy
shorelines cover about 1,000 acres along approximately 300
miles of tidal stream. During high tide they become submerged,
and at low tide they reemerge and expand in size.

Natural subsidence is occurring in coastal areas and documented
sea level increases are causing beachline erosion along the estuarine marshlands of the state. Storm
surges create additional shoreline erosion. Due to these forces, the habitat is always in a state of
transition. Urbanization is encroaching on some beaches where bulkheading and vegetation clearing is
taking place.

This subtype is imperiled in the state because of its rarity and due to very restricted range; subsidence,
sea level rise, hurricanes, and urbanization are other factors that make the subtype vulnerable to further
decline.

13.4 Mainland BeachesRange of Mainland

Natural Beaches