CHAPTER IV: WILDLIFE HABITATS FOR MISSISSIPPI’S SGCN,
THREATS AND CONSERVATION ACTIONS^168water control structures, which manage stream discharges. When used for flood control, reservoirs are
deeply flooded during the spring. During the summer and fall seasons, as water is evaporated and
released at the dam, wide drawdown zones that resemble marsh habitat are formed. The zones along the
periphery of the upper reaches of the reservoirs support large acreages of marsh and wetland scrub
communities. Some mudflats form during the late summer when water recedes from flooded riverine
habitats during the drier seasons of the year. The mudflats have been identified as important stopover
points for migrating shorebirds, which are regularly monitored at several locations throughout
Mississippi. Marshes are also created when wet bottomland or swamp forests are logged or opened by
natural disturbances. Unless artificially maintained, bottomland marshes represent a successional phase
lasting until trees and shrubs regain dominance. The longer a marsh persists, the more likely its
diversity will increase.
Marsh vegetation around lakes and ponds extends from the edge of saturated soils to a water depth of
around six feet. It exhibits a pattern of species zonation corresponding to water depth. The vegetated
zone normally does not extend beyond a six foot depth unless certain exotics, such as hydrilla, are
present. The deeper zones contain a variety of emergent aquatic plants such as pondweed, watershield,
sacred lotus and waterlily. Additional floating plants like duckweed, watermeal and bladderwort are
present. Shallower water and mucky saturated soils along the shoreline contain a diversity of aquatic
vascular species such as bulrushes, giant cutgrass, pickerel weed, cattail, rosemallow and primrose
willow along with numerous other graminoids and herbs. Other typical species include valley redstem,
cardinal flower, aquatic milkweed, jewelweed, common rush, hempvine, redtop panicgrass, camphor
pluchea, swamp smartweed, waterpod and lizard's tail. Coastal freshwater marshes contain a different
mix of species that includes white waterlily, irisleaf yelloweyed grass and jointed spikesedge. Introduced
exotic weeds such as alligatorweed, giant salvinia, hydrilla, water lettuce, Eurasian milfoil and water
hyacinth tend to overwhelm marshlands by their rapid and abundant growth.
LOCATION, SIZE, CONDITION AND CONSERVATION STATUS
EGCP, UEGCP, MSRAP
Freshwater marshes are usually found in small patches. Some marshlands may
be quite large in extent, up to 1,000 acres, if associated with large water control
structures such as dams and diversions. Large marsh habitats are found on the
upper end of reservoirs. Freshwater marshes occur throughout the state but are
more commonly found in lowlands and floodplains, especially in the
Mississippi Delta. They are adjacent to a variety of agricultural, forested and
urban lands. There are approximately 50,000 acres of freshwater marsh in the
state.
Fifty to seventy five percent of freshwater marsh habitats are estimated to have been lost in the central
Gulf states. The quality of freshwater marshes has also declined due to a variety of causes including the
Range of Freshwater Marshes