The Atchafalaya Basin is the nation?s largest river swamp, providing almost one and a half million acres of primarily bottomland hardwood and baldcypress-water tupelo swamp habitat interlaced by braided streams and bayous. The Atchafalaya Basin is rich with a myriad of species of plant, animal, and bird life, including about 60 species of reptiles and amphibians, over 270 species of birds, and almost 100 species of aquatic life.
Atchafalaya is a word from the Choctaw language meaning ?Long River?. The river itself stretches from Simmesport, LA about 140 miles to the Gulf of Mexico. The site includes 4 WMA?s: Attakapas Island, Elm Hall, Sherburne, and Thistlethwaite, as well as the Corps' Indian Bayou Recreation Area. It also includes Atchafalaya NWR and Bayou Teche Scenic Byway, otherwise known as Lake Fausse Point State Park.
The site includes the Morganza Floodway system, which is to be used to divert flood waters to protect New Orleans in the event of a monumental flood, and the East and West Atchafalaya Basin Protection Levees. The Army Corps partners with Louisiana Department of Wildlife and Fisheries (LDWF) and the U.S. Fish & Wildlife Service in managing the 600,000 acres that the Atchafalaya Basin Floodway System encompasses. Many of the divisions of this site share management and ownership with different entities, providing a collaborative effort to protect this site.
Another area of interest is Lake Fausse Pointe State Park. It occupies a 6,000-acre site which was once part of the Atchafalaya Basin. The construction of levees isolated the former Atchafalaya swampland. This park site lies within this isolated swamp, bounded on the east by the protection levee and on the west by the natural levee of Bayou Teche.
Bald Eagles nest in the tall cypress trees surrounding Lake Verret, and in many other locations throughout the IBA. There are many birds of prey in the basin, including forest inhabitants such as the Red-shouldered Hawk, Broad-winged Hawk, and Cooper's Hawk, Mississippi and Swallow-tailed Kites, Osprey, Barred, Great Horned, and Eastern Screech-Owls, American Kestrels, Merlin, and the occasional Peregrine Falcon and Northern Harrier.
A globally significant number of Wood Storks wander through the basin in late summer and early fall, and are the focus of The joint U.S. Army Corps of Engineers/LDWF fall Wood Stork Day. Several wading bird rookeries exist in the basin, with globally important numbers of White Ibis occurring at one large rookery. Yellow-crowned Night-Herons breed in large numbers in the cypress swamps, which are also home to many species of woodpeckers. Over 30 species of rails and shorebirds have been found in the wetland habitats in the basin.
The Atchafalaya Basin is world-famous for the numbers of American Woodcock resident in the Basin, which is central in the range of the bird. There are tens of thousands of American Woodcock that winter in the damp, brushy woods of hte Basin.
The Atchafalaya Basin also provides valuable stopover habitat for millions of Neo-tropical migrants, including many species of thrushes, vireos, flycatchers, warblers, buntings, and tanagers.
The site provides important breeding habitat for several Audubon WatchList species including Prothonotary, Kentucky, and Swainson?s Warblers, Wood Thrush,and Painted Bunting, and common birds such as Summer Tanager, Indigo Bunting, Great Crested Flycatcher, Eastern Tufted Titmouse, Carolina Chickadee, and Carolina Wren. During the winter migratory waterfowl species are present.
The most pervasive threats to the ecological functioning of the Atchafalaya Basin are altered hydrology and sediment delivery. The natural process of new land accretion has been rapidly accelerated since the 1950s, and increased sedimentation results in increased acreage of bottomland hardwood forest. Changes in hydrology, flooding regime, and elevation are resulting in degradation, loss, and lack of recruitment of baldcypress. Altered hydrology also leads to hypoxia and water stagnation, which impacts the aquatic species on which both humans and birds rely.
Agricultural pollution causes unnaturally high nutrient loads in the habitats of the Atchafalaya Basin. The basin can act as a sink for these nutrients, helping to reduce hypoxia in the Gulf of Mexico. However, the nutrient load adds further stress to fragile cypress-tupelo swamps.
While oil and natural gas activity has a reduced footprint compared to the past, it causes hydrologic alteration, habitat fragmentation and loss, and pollution. Canals from historical oil and gas practices fragment habitat and provide a conduit for invasive species, pollution, and saltwater intrusion.
Invasive species in the Basin include Giant Salvinia, Water Hyacinth, Hydrilla, Silver Carp, Chinese Tallow, and Nutria. Nutria kill cypress seedlings and saplings, further harming recruitment. Extensive growth by aquatic invasives can slow water movement, outcompete native plant species, and increase hypoxia.
Logging may be used for good forest management or may negatively impact habitats and species. Some prescriptions disrupt soils, leading to erosion, and can result in even-aged stands and young forests lacking trees of high wildlife value, particularly impacting endangered Louisiana Black Bear and birds that build large nests such as Bald Eagles. Tallow colonizes disturbed sites, reducing species diversity and the abundance of native wildlife trees. Logging further reduces the acreage of declining cypress-tupelo swamp.
A small portion of the Atchafalaya Basin IBA, Atchafalaya NWR, is owned by the federal government, as well as the Corps' Indian Bayou Recreation Area. The State of Louisiana owns several wildlife management areas within this IBA, including Attakapas Island WMA, Elm Hall WMA, Sherburne WMA, and Thistlewaite WMA. Bayou Teche Scenic Bayou, including Lake Fausse Point State Park, is also state-owned land in this IBA. The U.S. Army Corps of Engineers currently has 50,000 acres of land under fee management, some of which is included in the state WMA system at Sherburne and Attakapas (the Shatters Bayou area). The Corps is currently looking to purchase another 20,000 acres from willing sellers in the Basin. Much of the land within the Atchafalaya Basin IBA is privately owned.
The Atchafalaya Basin is mainly bottomlands and swamp habitat. The swamps mostly stay flooded year round with only periodic flooding in the bottomland hardwood portions. The terrain is flat swampland that floods regularly and receives siltation from the Atchafalaya River. The siltation is slowly increasing the land to water ratio in the Basin, and is leading to loss of some older cypress-tupelo swamps.
Forest cover on the upland areas is mostly oak, such as water oak, willow oak, overcup oak, cherrybark oak, nuttall oak, cow oak, and post oak. Cottonwood and sycamore are also present on the slightly higher areas, especially on the banks of oilfield canals. Other tree species present on upland sites are bitter pecan, sweet pecan, hickory, hackberry, sweetgum, ash, elm and maple. Midstory species encompass seedlings of dominant species along with boxelder, maple, red mulberry, and rough-leaf dogwood.
Predominant upper story trees of the lower-elevation areas are baldcypress and tupelo gum. Ground cover is sparse except in the areas where habitat modification such as timber management has taken place. In those places the ground cover is dense. Common species found include swamp dogwood, spice bush, French mulberry, greenbriar, rattan, blackberry, and many others. Japanese honeysuckle grows profusely in disturbed areas.
In 1992, Hurricane Andrew caused wide-scale destruction to the trees and land especially of Attakapas Island Wildlife Management Area. Many of the higher areas along the Atchafalaya River were reforested with cypress, ash, elm, water oak, nuttall oak, cherrybark oak, cow oak and other upland species. Also, roughly 30 miles of trails have been created and maintained around these reforested plots on the east and west sides of the Atchafalaya River.
Hunting is allowed on all publicly-owned lands except for Lake Fausse Point State Park. Hunted species include: migratory game birds such as American Woodcock and Wood Duck, small game such as rabbits, and large game such as deer. Beaver, nutria, otter, mink, muskrat, raccoon, bobcat, opossum, and alligator are trapped, and sport fishing is allowed. Major fish caught in the area include catfish, mullet, bass, bluegill, gar, bowfin, and freshwater drum. Crawfish are harvested commercially and recreationally: the state estimates that close to 22 million pounds of crawfish are harvested from the Basin annually.
Other commercial activities in the basin include timber harvest, oil and natural gas exploration and extraction, and energy production at the hydroelectric plant at the Old River Control Complex. There is a hazardous waste disposal site within the floodway. Agriculture occurs on the upland sites at the northern end of the Atchafalaya Basin.
Some residential and commercial development exists outside of the protection levees, but development in the basin is minimal. Habitats are fragmented by transportation and service corridors such as extensive pipeline networks, levees, roads, canals and power lines. These linear features change hydrology, nutrient, and sediment flow, and they result in changes in elevation, sometimes only of a few feet, that change species composition dramatically in a system that is a distributary of river waters.
Research activities occur in the basin. Other activities include nature walks, hiking, environmental education, boating, bird-watching, photography, environmental education, and natural area conservation. The Atchafalaya Basin is designated a Natural Heritage Area. Ecotourism centers around Acadian culture, food, and history. Sherburne WMA is managed and famous for Wild Turkey hunting and is the site of an outdoor festival, Step Outside Day, which occurs there every year on International Migratory Bird Day.