Wetlands & Other Wet Places

Submersed Marine Meadows
Shallow water flats or submersed meadows occur in and along the Mississippi Sound in the Gulf of Mexico. A number of algae such as Ulva spp. (sea lettuce), Entermorpha spp., and Polysiphonia spp. are common, especially in the cooler months.
Seagrass meadows (submerged aquatic vegetation or SAV) are particularly well-developed on the low energy sides of the barrier island chain. Not true grasses, about eight genera occur worldwide, and most of these are restricted to warm subtropical and tropical marine waters. Species seen in Mississippi include Thalassia testudinum (turtle grass), Cymodocia filiformis (manatee grass), Halodule beaudettei (sea grass) and Halophila engelmannia (shoal grass).

Estuarine and Coastal Marshes
Mississippi's estuarine ecosystems consist of shallow to deep water tidal habitats and adjacent tidal wetlands that are partially enclosed by land, but have open access to the ocean. The ocean water of the estuary is diluted by freshwater runoff from the uplands. Vegetated areas closest to the ocean have the highest salt concentrations and are characterized by tidal salt marshes. Marshes farthest from the ocean’s influence have the lowest salt concentrations and are normally termed intermediate marsh. Brackish marshes represent areas of wetland between the salt and intermediate marsh.

Salt Flats or Salt Pans
These communities comprise the saltiest plant communities that occur in Mississippi. Interstitial water salinities of 80-100 ppt or more are seen. Salt flats develop most often in barrier island marshes where evaporation of tidally inundated areas causes hypersaline conditions. Dwarf forms of Juncus roermerianus (black needlerush) and Spartina alterniflora (smooth cordgrass), Distichlis spicata (salt grass), Borrichia frutescens and Batis maritima (saltwort) are common. Deer Island has well-established dwarf needlerush pans.

Salt Marshes
These communities are usually dominated by herbaceous graminoids such as Spartina alterniflora (smooth cordgrass), Juncus roemerianus (black needlerush), Batis maritima (saltwort), and Distichlis spicata (salt grass).

Brackish Marshes
This community type is typically dominated by Juncus roemerianus (black needlerush), Spartina patens (marsh hay or wire grass), Scirpus americanus (three-cornered grass), S. robustus (saltmarsh bulrush), and Distichlis spicata (salt grass).

Intermediate Marshes
These oligohaline wetlands are characterized by narrow-leaved herbaceous perennials including Sagittaria lancifolia (bulltongue), Typha domingensis (southern cattail), Cladium jamaicense (sawgrass), Phragmites australis (common reed or roseau cane), Scirpus californicus (giant bulrush), and Echinochloa walteri (Walter’s millet).

Tidal Creek SAV's
In brackish shallows and in the shallows of tidally-influenced river discharges, we often encounter submerged meadows of various seasonal macro-algae including Chara spp. (muskgrass) and Nitella spp., and flowering plants such as Vallisneria americana (eel grass), Ruppia maritima (widgeon grass), Najas guadalupensis (southern water nymph), and Zannichellia palustris (hormed pondweed). In the more fresh reaches of tidally-influenced coastal streams, we often see the lettuce leaf-like foliage of submerged and floating leaves of spatterdock, Nuphar lutea.

Lacustrine Habitats
Lacustrine habitats include inland freshwater ponds and lakes, oxbows, dammed river channels, chutes, sloughs, barpits, bayous. Smaller bodies may be included here if they have a water depth greater than 2 m during low water periods. Mississippi's lacustrine environments generally lack persistent emergent plants (shoreline or littoral marshes), but are usually bounded by uplands or wetlands dominated by trees, shrubs or herbaceous emersed vegetation. While the assemblages generally vary somewhat with physiography and soil, bald cypress, black willow, buttonbush, red maple and similar species are nearly ubiquitous to lacustrine habitats in the state. Various submersed or floating aquatic plants are common: Azolla caroliniana (mosquito fern), Brasenia schreberi (water shield), Cambomba caroliniana (fanwort), Ceratophyllum demersum (coontail), Egeria densa (elodea or waterweed), Eichornia carassipes (water hyacinth), Hydrilla verticillata (hydrilla), Lemna spp. (duckweeds), Myriophyllum heterophyllum (parrot feather), M. aquaticum (parrot feather), M. pinnatum (eastern milfoil), M. verticillatum (whorled water milfoil), Najas guadalupensis (common water nymph), Nymphaea odorata (white water lily), Nelumbo lutea (American lotus), Salvinia spp. (water fern), Spirodela spp. (giant duckweed), Wolffia spp. (water meal), Wolffiella spp. (water star).

Palustrine Habitats - These are inland freshwater wetlands dominated by trees, shrubs, or other persistent emergent wetland vegetation. Palustrine habitats include small, shallow, permanent or intermittent water bodies. Included in the palustrine habitat type are freshwater marshes, swamps, and bogs. Stratification of the vegetation canopy is common in tree swamp and shrub swamp habitats.

Freshwater Marsh communities are dominated by emergent herbaceous perennials such as: Panicum hemitomum (Maidencane), P. virgatum (Switchgrass), Pontederia cordata (Pickerelweed), Alternanthera philoxeroides (Alligator Weed), Eleocharis spp. (the spikerushes), Juncus effusus (soft rush), Sagitarria lancifolia (bulltongue), S. latifolia (Arrowhead), S. montevidensis (Giant Arrowhead), S. graminea (Grassy Arrowhead),Scirpus cyperinus (bushy bulrush).

Forested Wetlands - Swamps, Cypress-Tupelo Swamps are permanently flooded except during periods of drought. The intermittently exposed soils are saturated through the entire growing season. The main trees occurring in these areas are baldcypress (Taxodium distichum) and water tupelo (Nyssa aquatica).

Common associates include: Acer rubrum var. drummondii (swamp red maple), Salix nigra (black willow), Fraxinus profunda (pumpkin ash), Shrubs and small trees also occur. These might include: Cornus drummondii (swamp dogwood), Cyrilla racemifolia (titi), Itea virginiana (Virginia willow). Some swamps are dominated by red maple, black willow, water elm or swamp privet, or associations of these.

Lianas are common and might include: Smilax spp. (greenbriar), Ampelopsis arborea (peppervine), Toxicodendron radicans (poison ivy), Pathenocissus virginana (Virginia creeper), Berchemia scandens (Rattan Vine)

Shrub Swamp communities are dominated by shrubs and small trees. These communities are seen in shallow wetlands often in slow-moving water courses such as creeks and bayous. Typical species include: Cephalanthus occidentalis (buttonbush), Baccharis halimifolia (Eastern saltbush),Sabal minor (Dwarf palmetto), Myrica cerifera (wax myrtle), Foresteria acuminata (swamp privet)

Bottomland Forests occur in the broad floodplains of river systems. Species composition varies with latitude, elevation, degree and frequency of flooding, and stage of succession. These forests have two basic strata, including the tree canopy itself and a shrubby understory. Light is poor in the understory, thus the herbaceous community is poorly developed and is mainly seen only in the winter and spring in various annuals and perennials.
Common tree species include: Acer rubrum (Red Maple), A. negundo (Boxelder), Carya aquatica (Swamp or Water Hickory), C. illinoensis (Pecan), Celtis laevigata (sugarberry), Fraxinus pensylvanica (green ash), Liquidambar styraciflua (Sweetgum), Platanus occidentalis (sycamore), Quercus lyrata (overcup oak), Q. nigra (water oak), Q. michauxii (cow oak), Q. nuttalii (striped oak), Q. phellos (willow oak), Ulmus alata (winged elm), U. americana (American elm), Salix nigra (Black willow). Understory trees and shrubs might include: Cornus drummondii (swamp dogwood), Morus rubra (red mulberry), Crataegus spp. (hawthorn), Planera aquatica (water elm), Cephalanthus occidentalis (buttonbush), Sabal minor (Dwarf Palmetto)

Bayhead communities occur in the lower coastal plain areas of the state and develop in branch heads of streams and swamp borders. The soils are sandy and acidic and are saturated or inundated throughout most of the growing season.
Vegetation consists mostly of water-tolerant trees - including various kinds of "bays" including: Magnolia virginiana (sweetbay) Nyssa sylvatica var. biflora (black tupelo) , Persea palustris (redbay). The understory typically consists of species such as: Cyrilla racemiflora (titi), Ilex coriacea (large gallberry), I. glabra (inkberry), I. vomitoria (yaupon), Itea virginiana (Virginia willow), Lyonia lucida (fetterbush), Leucothe axillaris (dog-hobble), L. racemosa (sweetbells),Viburnum spp.

Wet Pine Savanna communities are ubiquitous to the Gulf coastal area. These are essentially flatwoods "bogs" with scattered longleaf pine (Pinus palustris), loblolly pine (P. taeda) or slash pine (P. elliotii). Wetter areas may also support pond cypress (Taxodium distichum var. ascendens). Maintenance of the open savanna is fire-dependent and various shrubby species (Ilex mainly), vines (mainly Smilax laurifolia) and hardwoods will invade without periodic fire.

Bog Habitats - True bogs, that is, oligotrophic wetlands dominated by herbaceous vegetation that form peat from aquatic mosses (sphaghnums), are somewhat uncommon in the state, but do occur here and there where the conditions are just right. Although our carnivorous plant-dominated areas in the mostly Gulf coastal counties are usually called "bogs", these usually do not have hydrologies conducive to sphagnum growth and peat accumulation. In fact, the soils of most of our carnivorous "bogs" are very low in organic matter (and nutrients).

Hillside Bog communities occur where subsurface strata consist of impermeable clay or rock such that the water table is perched and accumulates at or near the surface. These sites support a high diversity of plant species including: Sphagnum spp. (Bog moss), Rhynchospora spp., Fuirena spp., Scleria spp., Sarracenia alata (yellow pitcher plant), Eriocaulon compressum (Flattened Pipewort), E. decangulare (common pipewort), Xyris spp. (Yellow-eyed Grass).

Flatwoods Bog communities occur in piney woods regions and mixed hardwood-pine flatwood areas. They develop in shallow depression areas and hold water due to subsoil clay pans. These communities are wet for most of the year. Our Gulf coastal flatwoods bogs typically some of the highest plant species diversity of any plant community in the state. Plants growing in these warm coastal wetlands are mainly herbaceous perennials. Very few annuals occur. The main plant families represented include the grasses, sedges, rushes, orchids, asterids, and liliaceous families. These areas support perhaps the most diverse assemblages of carnivorous plant species seen in the southeastern U.S. Pitcher plants, sundews, butterworts, and bladderworts are ubiquitous to these communities. Fire is critical to maintenance of these areas as open bogs. Some of the more common species encountered include: Calopogon spp. (Grasspink orchid), Sarracenia spp. (pitcher plants), Utricularia spp. (bladderworts), Drosera spp. (sundews), Lacnanthes caroliniana (redroot), Lophiola americanum (golden-crest).