Tuesday, February 16, 2010

Coastal Louisiana

Coastal Louisiana

Beaver Dam, Louisiana

About 40 percent of the coastal wetlands in the lower 48 states are found in Louisiana. These millions of acres of wetlands were built over thousands of years by Mississippi River floodwaters that deposited huge amounts of sediment at the river's delta.

Today, these wetlands range from interior forested wetlands to barrier islands on the Gulf of Mexico and a wide array of interconnected habitats, including freshwater, brackish and salt marshes that are home to millions of birds and other wildlife.

People Depend on the Louisiana Coast

Almost half of the population of Louisiana lives near the coast, including in the city of New Orleans. The coast's unique culture is made up of people whose way of life is tied to the bayous, including Acadians (Cajuns), American Indians and other peoples who have settled there from all over the world.

Much of Louisiana's Economy is Tied to its Coast and Wetlands:

  • Louisiana has extremely productive commercial fisheries.
  • The wetlands and wildlife draw birders, hunters, anglers, boaters and other outdoor enthusiasts.
  • The navigable waterways, including the Mississippi River, support shipping and transit.
  • The offshore oil fields and refineries provide numerous jobs.

The wetlands that make up most of coastal Louisiana are an extremely valuable resource that provides critical services to people, called ecosystem services. They not only provide seafood and wildlife for us to enjoy, but also improve water quality by filtering out pollutants and absorbing excess nutrients, replenishing aquifers, providing erosion control and helping to dissipate storm surges.

Man with fish he caught

Wildlife in Coastal Louisiana

The Louisiana coast has a diversity of habitats--from uplands to the open waters of the Gulf of Mexico, and everything in-between, including wet forests with cypress trees, freshwater marsh, brackish marsh salt marsh and sandy beaches. These habitats provide homes for an abundance of migratory and year-round wildlife.

  • Endangered species: Coastal Louisiana has a number of federally endangered or threatened animals, such as the Louisiana black bear, piping plover and green sea turtle, that struggle to survive in the remaining coastal habitat.
  • Plants: The Louisiana coast has many plants that live only in wetlands and that provide habitat for wetland wildlife. Some of these plants are cattails, swamp rose, spider lilies, and cypress trees.
  • Fish and shellfish: Estuaries and wetlands are nurseries for young fish and shellfish.
  • Migratory Birds: The Louisiana coast is where the Central and Mississippi flyways meet. It provides a place for Neotropical migratory songbirds to rest and feed before or after crossing the Gulf of Mexico, and it is a winter home to 70 percent of the waterfowl that migrate along these flyways, such as the gadwall, green-winged teal, northern shoveler, and snow goose.
  • Reptiles: The American alligator is a well-known resident of the Louisiana coast.

Threats to Coastal Louisiana

Alligator with its mouth open

Wetland Loss

At one time there were extensive wetlands around New Orleans and other coastal communities that provided a natural resilience to storms. In total, about fifty miles of marshland once protected New Orleans from the Gulf with trees and marsh grasses that blocked the winds and blunted storm surges. Today, coastal Louisiana is losing 24 square miles of wetlands each year--roughly equivalent to a football field every 30 minutes. Louisiana has already lost an area of coastal land equal to the size of the state of Delaware! If this rate of wetland loss is not slowed, by the year 2040 the Louisiana shoreline will advance inland as much as 33 miles in some areas.

Wetland loss occurs because of natural causes--subsidence and wave erosion--and human causes.

How Do People Cause Wetland Loss?

  • Construction of river levees, channels, canals and dams that regulate water flows or make it easier for ships to pass through an area.
  • Draining wetlands for agriculture or urban development

Human activities disrupt the natural balance of Louisiana wetlands. Prior to human development, natural wetland loss was replenished by Mississippi River sediments and nutrients creating new wetlands. Human activities have the unfortunate side-effect of causing Mississippi River sediments to go straight down the river's channel and into the Gulf of Mexico. Not only are we destroying wetlands, but we are disrupting the natural cycle that rebuilds them.

In the aftermath of Hurricane Katrina, one of the lessons learned is that a healthy system of wetlands between New Orleans and the Gulf almost certainly would have slowed down the storm and dampened the storm surge. Without natural storm buffers, breaches in levees such as those after Hurricane Katrina could become an even bigger threat. Wetlands serve as nature's first line of defense--by absorbing much of damage caused by hurricanes.

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