Public Lab Wiki documentation

Gulf Coast Wetlands

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Contributors to this wiki include: Jay McIlwain, Amy LeGaux and Stevie Lewis

There are many types of wetlands here in the Gulf Coast. In many places, wetlands are the closest ecosystem to the water’s edge, and can even be found within the boundaries of our urban communities.

Global Green has a great resources that helps explain the basics of wetlands, what they are and why they are important.

Here on the Gulf Coast, there are specific types of wetlands we find that are rare and unique including emergent marsh and wet pine savanna. Below we will explore some of the characteristics of wetlands found here on the Gulf:

Emergent Marsh Wetland

Characteristics: This wetland tends to be at the lowest elevation, closest to the shore of the Gulf. The water is brackish and the species that live there are tolerant to salt water environments. The soil in this ecosystem tends to be silty/clay mixture with organic material and peat.

Examples of this wetland: Examples of this wetland can be found in the South Louisiana Bayous.

Species: Flora in this ecosystem include Spartina alterniaflora (smooth coordgrass or saltmarsh cordgrass) and Juncus romerianus (balck needlerush). Fauna in this ecosystem include shorebirds, wading birds, pelicans, gulf salt marsh snake, diamondback terrapins and alligators.

Ecosystem Functions: This ecosystem is an important nursery for small fish, crabs and oysters. It is also a feeding ground for larger fish. This marsh also acts as a filter absorbing water as it travels up in high tied, or down from the land in runoff from rain events. For human benefits, this marsh is also often cited as protection for our coastal communities from storm surge. It also is highly valued for recreation boating and fishing.

Pressures on this ecosystem: Pressures on this ecosystem include sea level rise, dredging, water quality threats from things like marine litter and oil spills, habitat loss from construction and fill in, lack of renourishment from suppressed flooding events and increased wave action from boating, hypoxia caused by agricultural runoff and invasive species such as nutria.

More information:

Freshwater Marsh

Characteristics: Water in these systems tend to be fresh, the soils are peaty, or on stream edges, sandy soils or clay.

Examples of this wetland: An example of this wetland can be found by the coastal bays where freshwater empties into the bay.

Species: Flora that can be found in this ecosystem include Cladium jamaicense (sawgrass) Juncus and various rushes. Fauna in this ecosystem include turtles, cotton mouth snakes, king snakes, egrets, herons, wading birds, catfish, bass, bream and raccoons.

Ecosystem Functions: This ecosystem acts as a nursery for small fish, it also helps to filter water before it enters the waterway. It acts as a transitional area between uplands and lowlands.

Pressures on this ecosystem: Pressures on this ecosystem include water quality threats (runoff from agriculture, roadways and septic tanks), loss of habitat from construction and filling in. It is also threatened by increased sheet flow, or the amount of impervious serves that water runs off into it from. This reduces the natural filtration system and can cause siltation and sediment loading. Litter is also a big problem in this marsh as well as contamination from marine oils and debris. Invasive species in this habitat include apple snails, hematodes, tallow trees and tilapia.

More information:

Wet Pine Savanna

Characteristics: Wet Pine Savannas are a fire dependent habitat. There is not always standing water in these wetlands, but they have hydrologic soils and act as a filter to lower wetland areas.

Examples of this wetland: Wet pine savannas such as those seen at the Sandhill Crane National Wildlife Refuge, can be found in the uplands all along the Gulf.

Species: Flora that can be found in this ecosystem include wiregrass, Spartina patens (saltmeadow cordgrass), carnivorous plants such as pitcher plants and sundews, and Pinus plustris (longleaf pine). Fauna in wet pine savannas include sandhill cranes, deer and various rodents.

Ecosystem Functions: Historically, these savanna’s were used to harvest turpentine. Their timber is also really valuable and they are great habitat for many species.

Pressures on this ecosystem: Because it is fire dependent, many of these wetlands are at risk of fire suppression. As many people live in or near this habitat, there tends to be fragmentation of the habitat and the interest to suppress the fire that is needed reduce the fuel load and rejuvenate the wetland. Invasive species in this ecosystem are also a big problem. Tallow trees, cogon grass and camphor trees all threaten this habitat. There are also feral hogs.

More Information:

Bottomland Hardwood Wetland

Characteristics: This system is often found near rivers. The water is fresh, but often very tannic. Because it’s near river systems, there tend to be a number of oxbow lakes that can be found supporting this type of ecosystem.

Examples of this wetland: An example of this wetland can be seen in Bayou Bienvenue in the lower 9th ward.

Species: Species that can be found in this ecosystem include cypress trees, black gum trees and tupelo gum.

Ecosystem Functions:

Pressures on this ecosystem: Pressures on this ecosystem include construction, water quality threats, hydrologic flow being tampered or redirected, litter and invasive species such as popcorn trees and Japanese climbing fern.

More Information:

Stormwater restoration wetlands

Characteristics: This wetland is generally built by people in order to filter stormwater from rain events in urban areas. These wetlands can also sometimes act as rain gardens or bioswales.

Examples of this wetland: One example of this wetland is the stormwater wetland site in City Park in New Orleans.

Species: Cattails, swamp rose, various marsh grasses.

Ecosystem Functions: Built wetlands have many ecosystem functions, they are be used to slow the drainage of water into the water table, to absorb heavy metals and pollutants preventing them from entering our water systems and even in some case, provide habitat.

Pressures on this ecosystem: Pressures on this system include, pollution, invasive species and construction.

For more wetland type information:

What to monitor for in wetlands

Wetland health can be assessed through a number of means:
Aerial Mapping can help you gather information about the big picture:
1) understanding and visualizing pressures on the larger ecosystem such as development, flooding etc.
2) vegetation growth
3) shoreline migration

Surveys for species types and invasive species are also good things to monitor for in wetlands,
1) Knowing what they are,
2) How many of them there are,
3) If they’re populations are shifting and
4) How they are affecting the rest of the marsh species.

Infrared and near infrared photography such as that captured by the infragam camera can help you assess the changes in plant health.

Understanding and monitoring for water quality is also good monitoring technique on wetlands. Good water quality is a good indicator of a healthy wetland. Some useful water quality parameters include:
1) Depth
2) Turbidity
3) Temperature
4) Dissolved Oxygen
5) pH
6) Conductivity
7) Nitrates/phosphates

More information on water quality parameters can be found here:

Restoring wetlands and restoration sites:

Wetland restoration projects can be found all over the US. The major goal behind most restoration projects are to restore wetland habitat function and quality. The same monitoring techniques can be used in restoration sites as current wetlands.

More information on wetland restoration: