The wetlands of Louisiana are water-saturated

coastal The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in ...

and

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

regions of southern

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is bord ...

, often called 'Bayou'. The Louisiana coastal zone stretches from the border of

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

to the

Mississippi Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...

line and comprises two wetland-dominated ecosystems, the Deltaic Plain of the Mississippi River (unit 1, 2, and 3) and the closely linked Chenier Plain (unit 4). The Deltaic Plain contains numerous barrier islands and headlands, such as the

Chandeleur Islands The Chandeleur Islands (french: Îles Chandeleur) are a chain of uninhabited barrier islands approximately long, located in the Gulf of Mexico, marking the outer boundary of the Chandeleur Sound. They form the easternmost point of the state of L ...

, Barataria Basin Barrier Islands, and Terrebonne Basin Barrier Islands. The ''Coastal Wetlands Planning, Protection and Restoration Act'' (CWPPRA) program, through the NOAA Habitat Conservation National Marine Fisheries Service funded $102 million in construction for deteriorated wetlands and barrier island habitats.

Geography

The

Environmental Protection Agency A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale ...

defines

wetlands A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The p ...

as "those areas that are inundated or saturated by surface or groundwater at a frequency and duration water to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions (e.g.

swamps A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; a ...

fen A fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires ...

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found ...

es, and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environme ...

)." Different wetland types arise due to a few key factors, primarily: water levels, fertility, natural disturbance and salinity.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Around Lake Pontchartrain, for example, these few factors produce wetlands including bottomland hardwoods, cypress swamp, freshwater marsh and

brackish marsh Brackish marshes develop from salt marshes where a significant freshwater influx dilutes the seawater to brackish levels of salinity. This commonly happens upstream from salt marshes by estuaries of coastal rivers or near the mouths of coastal riv ...

. High levels of flooding reduce the abundance of trees, leaving four principal marsh types: saline, brackish, intermediate and fresh. Although these areas make up a very small percentage of the total land found in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, southern Louisiana contains 40 to 45 percent of the wetlands found in the lower states. This is because Louisiana is the drainage gateway to the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

for the Lower Mississippi Regional Watershed. The Lower Mississippi Regional Watershed drains more than 24 million acres (97,000 km²) in seven states from southern

Illinois Illinois ( ) is a state in the Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolitan areas include, Peoria and Rock ...

to the Gulf of Mexico. Hence the wetlands of this area are important at the national scale. On the east side of Louisiana, coastal wetlands intergrade with long leaf pine savannas, which support many rare and unusual species such as pitcher plants and gopher tortoises.Keddy, P.A. 2008. Water, Earth, Fire: Louisiana's Natural Heritage. Xlibris, Philadelphia. 229 p. On the western side, they intergrade with wet prairies, an ecosystem type that was once vast, and now has been all but eliminated. The larger vertebrate fauna such as wolves and bison was exterminated. The eastern coastline of Louisiana is much more susceptible to erosion than the western coastline because much of the eastern coastline was created by silt deposits from the

Mississippi River The Mississippi River is the List of longest rivers of the United States (by main stem), second-longest river and chief river of the second-largest Drainage system (geomorphology), drainage system in North America, second only to the Hudson B ...

. This natural process of sediment deposition has been blocked by an extensive levee system that directs flood water past wetlands. The western coastline is

y, but the marshes only extend inland by at the most, then the elevation begins to increase and the marshes fade into solid grounded

prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...

s. Therefore, rising sea levels due to

global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

and

coastal erosion Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landwar ...

, may not affect the western coastline as profoundly as it will the eastern half, which may be replaced in open water over substantial areas.

Loss of the wetlands

The wetland lose of southern louisiana due to human activities

The wide range of benefits provided by the wetlands of this region were not recognized by a majority of policy makers in the early 20th century. Wetlands provide vital ecological services including flood control, fisheries production, carbon storage, water filtration and enhanced disagreement over the relative importance of these factors, although it is probably safe to say that the two major factors now acting are subsidence, mostly from lack of sediment, and salt water intrusion from canals dredged to service oil and gas wells and facilitate oil and gas exploration. Further wetland loss is attributed to the construction of the now-closed

Mississippi River Gulf Outlet Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Missis ...

, which introduced salt water into freshwater and intermediate marshes and facilitated significant erosion. A brief explanation of various causes follows. Subsidence of the coast is certainly occurring. Some people blame the direct effects of oil and gas extraction. The logic is that as billions of barrels of oil and saltwater and as trillions of cubic feet of gas were removed from the

reservoirs A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including control ...

in which they had accumulated over millions of years, these reservoirs lost their ability to support the weight of the rocks above. As these structures slowly collapsed, the soil above gradually subsided. The wetlands on the surface began to sink into the gulf waters. Others argue that subsidence is a natural process in deltas, as sediments compress, and that the real problem is the lack of flood waters that would normally deposit new layers of sediment.Boesch, D. F., Josselyn, M. N., Mehta, A. J., Morris, J. T., Nuttle, W. K., Simenstad, C. A., and Swift, D. P. J. (1994). Scientific assessment of coastal wetland loss, restoration and management in Louisiana. Journal of Coastal Research, Special Issue No. 20. The role of hurricanes is also a matter of disagreement; some studies show that hurricanes actually build elevation in marshes. Another factor is rising sea levels estimated to be about 2mm per year associated with global warming. Sediment compaction is also a significant source of wetland loss. Compaction rates have been conservatively estimated at 5mm to 10mm or more per year for the organic-rich

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

sediment (

peat Peat (), also known as turf (), is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. The peatland ecosystem covers and ...

) that predominates the

Mississippi River Delta The Mississippi River Delta is the confluence of the Mississippi River with the Gulf of Mexico in Louisiana, southeastern United States. The river delta is a area of land that stretches from Vermilion Bay on the west, to the Chandeleur Isl ...

environment. Given the ubiquity of this compaction-prone sediment in southern Louisiana, coastal restoration project managers (see:

Louisiana Coastal Protection and Restoration Authority The Louisiana Coastal Protection and Restoration Authority (CPRA) is a governmental authority created by the Louisiana Legislature in the aftermath of Hurricanes Katrina and Rita. The organization takes advantage of both federal and state funding ...

) must consider the underlying geology of their regions prior to development as to not exacerbate rates of compaction. An extensive

levee A levee (), dike (American English), dyke (Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually earthen and that often runs parallel to the course of a river in its floodplain or along low-lying coastli ...

system aided by locks and dams has been developed in the waterways of the lower Mississippi River. The levees (designed to prevent flooding along the waterways) prevent needed sediment from being distributed into the marshes downriver. With no new accretion and with steady subsidence, the wetlands slowly are replaced by encroaching saltwater from the Gulf. As a result of this apparent engineering dilemma, large areas of marsh are being lost to the ocean. Since 1930 water has consumed more than 1,900 square miles (4,900 km²) of the state's land. This loss equates to the disappearance of 25 square miles (65 km²) of wetlands each year, or a football field sized area every 30 minutes. This loss can be reversed (at least in some areas) but, only with large scale restoration, including the removal of levees to allow the Mississippi River to carry sediment into these areas. Another factor that damaged wetlands was large scale logging, particularly the extensive logging of cypress forests in the early 1900s. One early logger described it this way: "We just use the old method of going in and cutting down the swamp and tearing it up and bringing the cypress out. When a man's in here with all the heavy equipment, he might as well cut everything he can make a board foot out of; we're not ever coming back in here again". This logging often required construction of canals, which, once the logging was finished, allowed salt water to enter the wetlands and prevent regeneration of the cypress. As if these problems were not enough, the introduction of nutria from South America in the 1930s provided an entirely new species of grazing mammal. Although only a few escaped, there are now millions. Natural grazing by muskrat was now accelerated by grazing from nutria. By removing plants, nutria both cause loss of vegetation, and, perhaps more seriously, a loss of dead organic matter which would otherwise accumulate as peat and raise the level of the marsh One of the most important natural controls on nutria is large alligators, which may provide a useful tool for biological control of nutria, and therefore for reduced impacts of grazing. Southern Louisiana's disappearing wetlands have a broad impact ranging from cultural to economic.

Commercial fishing Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must oft ...

in Louisiana accounts for more than 300 million dollars of the state's economy. More than 70% of that amount stems from species such as

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are ref ...

oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not ...

s and

blue crabs Blue crab may refer to: * Blue Crab 11, an American sailboat design * ''Callinectes sapidus'' – Chesapeake or Atlantic blue crab of the West Atlantic, introduced elsewhere * '' Cardisoma guanhumi'' – blue land crab of the West Atlantic * ''Disc ...

that count on the coastal wetlands as a nursery for their young. Annually Louisiana sells more than 330,000 hunting licenses and 900,000 fishing licenses to men and women who depend on the wetlands as a habitat for their game. Additional recreational activities such as boating, swimming, camping, hiking, birding, photography and painting are abundant in wetland areas. Wetlands host a variety of trees such as the

bald cypress ''Taxodium distichum'' (bald cypress, swamp cypress; french: cyprès chauve; ''cipre'' in Louisiana) is a deciduous conifer in the family Cupressaceae. It is native to the southeastern United States. Hardy and tough, this tree adapts to a wide ...

, tupelo gum and cottonwood. Other plants such as the

dwarf palmetto ''Sabal minor'', commonly known as the dwarf palmetto, is a small species of palm. It is native to the deep southeastern and south-central United States and northeastern Mexico. It is naturally found in a diversity of habitats, including maritime ...

and

wax myrtle ''Myrica'' is a genus of about 35–50 species of small trees and shrubs in the family Myricaceae, order Fagales. The genus has a wide distribution, including Africa, Asia, Europe, North America and South America, and missing only from Austral ...

and submerged aquatic plants such as '' Vallisneria'' and '' Ruppia'' are native to Louisiana wetlands. Wetland plants act as natural filters, helping to remove heavy metals, sewage, and pesticides from polluted water before reaching the Gulf of Mexico. Animal species native to these areas include

osprey The osprey (''Pandion haliaetus''), , also called sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor reaching more than in length and across the wings. It is brown o ...

anhinga The anhinga (; ''Anhinga anhinga''), sometimes called snakebird, darter, American darter, or water turkey, is a water bird of the warmer parts of the Americas. The word ''anhinga'' comes from ''a'ñinga'' in the Brazilian Tupi language and means ...

ibis The ibises () (collective plural ibis; classical plurals ibides and ibes) are a group of long-legged wading birds in the family Threskiornithidae, that inhabit wetlands, forests and plains. "Ibis" derives from the Latin and Ancient Greek word ...

heron The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychu ...

egret Egrets ( ) are herons, generally long-legged wading birds, that have white or buff plumage, developing fine plumes (usually milky white) during the breeding season. Egrets are not a biologically distinct group from herons and have the same buil ...

manatee Manatees (family Trichechidae, genus ''Trichechus'') are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows. There are three accepted living species of Trichechidae, representing three of the four living speci ...

alligator An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additional ...

s, and

beaver Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers a ...

s. Although there are several naturally occurring forces that adversely affect the wetland regions of Louisiana, many believe it is human intervention that has caused the majority of the decline.Tidwell, Mike. ''The Ravaging Tide: Strange Weather, Future Katrinas, and the Coming Death of America's Coastal Cities'', Free Press, 2006. Prior to the building of

s on the

, the wetlands were kept in balance by occasional floods, which fill the area with sediment, and

subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope mov ...

, the sinking of land. After the levees were built, however, flood sediment flowed directly into the

. This subsidence along with the recent

sea level rise Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cr ...

tipped the balance toward subsidence rather than marsh growth. This, along with the

canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface f ...

s built in the area, caused decline of the wetlands and also caused less weakening of and less protection from recent hurricanes such as

Hurricane Katrina Hurricane Katrina was a destructive Category 5 Atlantic hurricane that caused over 1,800 fatalities and $125 billion in damage in late August 2005, especially in the city of New Orleans and the surrounding areas. It was at the time the cost ...

. The Lake Pontchartrain Basin Foundation has developed a comprehensive management plan for the eastern regions of the Louisiana coast, placing emphasis upon restoration of river habitats, cypress swamps and fringing marsh. This could be a model applied to other coastal regions.

Oil company canals

The dredging of access canals by oil companies has long been considered to be a cause of coastal erosion. These concerns were raised in 1925 and continued with a 2013 lawsuit against many oil companies.

Policy and protection

The

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditi ...

(NOAA) enacted the ''Coastal Zone Management Act of 1972'' (CZMA) amended by ''16 U.S.C. 1451 et seq.'' that includes Louisiana, to develop plans providing assessment priorities for land conservation needs. The agency provides guidance in selecting conservation projects in the state. In 2002 the Secretary of Commerce was directed by Congress to establish the Coastal and Estuarine Land Conservation Program (CELCP), "for the purpose of protecting important coastal and estuarine areas that have significant conservation, recreation, ecological, historical, or aesthetic values, or that are threatened by conversion from their natural or recreational state to other uses", through the ''Department of Commerce, Justice, and State Appropriations Act of 2002'' by ''Public Law 107-77''. This was re-authorized in 2009 by the Omnibus Public Land Management Act (P.L. 111-11). In 2002, Congress directed the Secretary of Commerce to establish a Coastal and Estuarine Land Conservation Program (CELCP) "for the purpose of protecting important coastal and estuarine areas that have significant conservation, recreation, ecological, historical, or aesthetic values, or that are threatened by conversion from their natural or recreational state to other uses" (The Department of Commerce, Justice, and State Appropriations Act of 2002, Public Law 107-77). CELCP was re-authorized in 2009 as part of the Omnibus Public Land Management Act (P.L. 111-11). The Louisiana Department of Natural Resources, Office of Coastal Management, Inter-agency Affairs and Field Service Division (LDNR/OCM/IAFSD) became the lead agency for implementing a state coastal management program, or CELCP program, based on federal guidelines. Louisiana chose the conditionally approved Coastal Nonpoint Pollution Control Program (CNPCP) boundaries. On January 23, 2008, the Governor of Louisiana signed Executive Order No. BJ 2008-7, creating the Coastal Protection and Restoration Authority (CPRA), that implemented the Integrated Ecosystem Restoration and Hurricane Protection plan, becoming known as the "Master Plan."

References

External links