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Wide-based cypress trees emerge from water in a swamp.
Information icon Cypress swamp at Big Lake NWR. Photo by Jeremy Bennett.

Next Steps for a Healthy Gulf of Mexico Watershed

Atchafalaya Basin

Landscape at a Glance

A map showing the Atchafalaya Basin.
Map of Atchafalaya Basin focal area by Roy Hewitt, USFWS.

The Atchafalaya River originates in south-central Louisiana as the largest distributary of the Mississippi River and flows south for approximately 140 miles, emptying into the Gulf at Atchafalaya Bay, approximately 15 miles south of Morgan City, Louisiana. The Atchafalaya River Basin is home to the largest contiguous river swamp in the United States, which is maintained by receiving approximately 30 percent of the flow of the sediment rich waters of the Mississippi River. This focal area is characterized by extensive and diverse wetland habitats ranging from bottomland hardwoods and cypress-tupelo swamp, to freshwater marshes that transition to brackish and saline marshes as the river forms the only accreting delta system (Wax Lake and Atchafalaya) in the Gulf. Nourished by annual floodwater inputs, the wetland ecosystems of the Atchafalaya River Basin Focal Area support an abundance of resident and migratory fish and wildlife species.

The abundant natural resources of the area have been integral to the history and culture of Native Americans and Acadians, and continue to support local economies through commercial fishing, timber harvest, oil and gas development, navigation, outdoor recreation and tourism. These activities and resource interests also present challenges to the long-term ecological health of this focal area. Ecological threats arise from hydrological alterations for navigation and flood control, which include hypoxia; extremes in sedimentation (i.e., too little or too much); habitat fragmentation; lack of connectivity between the river and floodplain; and the proliferation of invasive species.

A bright green vine covers water.
Water hyacinth, an invasive species proliferating throughout the Atchafalaya Basin. Photo by Steve Hillebrand, USFWS.

The Service believes that focusing efforts on habitat connectivity through the Atchafalaya River system, restoring hydrology within the floodplain, enhancing regeneration of forested wetlands, and conserving habitat for resident and migratory wildlife will support resiliency of the ecosystem and the region’s endemic culture.

Target Species

The Atchafalaya River Basin is a subcomponent of the Mississippi Alluvial Valley (MAV) ecosystem and many of its species objectives are derived and shared with the broader MAV focal area. However, unlike the broader MAV, this focal area is predominantly forested. As a result, conservation actions here are primarily focused on forest-dependent species. Conservation of these forested systems is important to maintain the forest patch sizes necessary to sustain populations of swallow-tailed kites (320 breeding pairs for entire MAV) and songbirds, as well as to maintain the habitat connectivity and population viability required to sustain the recovery status of the recently delisted Louisiana black bear. Management actions can improve the structure and composition of these forests for the benefit of these species as well as many wintering migratory birds (e.g., the American woodcock, which require access to early successional habitats at some time during the winter). In addition to maintaining forest block size and conducting management practices to improve forest habitat, another priority management need in the Atchafalaya River Basin includes the restoration of water flows for the benefit of both fish and the cypress regeneration that provides important nesting habitat for bald eagles and colonial water birds.

A large black bear eating grass.
The Louisiana Black Bear, removed from the Endangered Species List in 2016. Photo by Pam McIlhenny; used with permission.

While many of the proposed actions in this focal area are specifically included for their benefits to our target species, improving water and sediment distribution in the floodplain will improve crawfish production and freshwater sportfish (e.g., alligator gar and Gulf Coast striped bass) populations. Similarly, freshwater and marine species of sportfish, shrimp, and blue crabs will benefit from healthy coastal wetlands as a result of freshwater diversion. These same species will also benefit from invasive species management. Restoration in these swamps also benefit a number of important game species, including the American alligator, the white-tailed deer, and the wild turkey.

High Priority Actions Based on the Service’s Vision

Protect and restore bottomland hardwood and cypress-tupelo forests for increased habitat buffer and connectivity to benefit the Louisiana black bear, neotropical migrant landbirds, and other forest species, and to provide habitat for wading birds, aquatic species and waterfowl.

Next Steps

A biologist poses for a photo in front of some fallen tree debris.
Native cypress tree re-planting. Photo by Tom MacKenzie, USFWS.
  • Partner with the U.S. Army Corps of Engineers and other stakeholders to strategically implement the congressionally authorized 2007 Atchafalaya Basin Floodway System in collaboration with state and federal agencies, private landowners, conservation organizations and other Atchafalaya River Basin stakeholders. Key elements include working with willing sellers to acquire 70,000 acres for public access and 367,000 acres of environmental easements.
  • Work with willing sellers to protect and restore wildlife habitat within the approved acquisition boundaries of the Atchafalaya and Bayou Teche NWRs through a combination of fee acquisitions, conservation easements and agreements; and through land exchanges with other federal agencies.
  • Implement land conservation and associated forest management practices (e.g., timber harvest, thinning and regeneration) that provide a mix of habitats necessary for the suite of forest species and ensure high quality wintering habitat for American woodcock.
  • Focus on increasing contiguous forested habitat and providing forested corridors between intact habitat blocks, such as securing wildlife (e.g., Louisiana Black Bear) movement corridors across U.S. Highway 90.
  • Identify potential sites to improve swamp habitat and health of forest stands for wildlife, such as lands in agricultural production (e.g., areas of the Morganza Spillway that have potential for conversion back into bottomland hardwoods) and cypress-tupelo wetland forest that could be restored through plantings and regeneration.
  • Work with the Louisiana Department of Wildlife and Fisheries to implement their green infrastructure network for Wildlife Management Area and NWRs.

Restore hydrology and improve water and sediment distribution in the Atchafalaya River floodplain and to coastal wetlands by implementing sediment management practices and hydrological features that aid in the redirection of sediment and water to areas where those resources are in deficit or are in excess.

Next Steps

  • Partner with USGS, U.S. Army Corps of Engineers, the state of Louisiana and stakeholders to evaluate current science and information regarding hydrology and sediment dynamics to provide a basis for developing restoration science needs.
  • Support existing water monitoring gauges and increase overall real-time monitoring to enhance understanding of basin hydrology; explore the potential to expand the Coastwide Reference Monitoring System into the basin.
  • Work with the state of Louisiana to implement Atchafalaya Basin projects for water management, including activities such as removing/reducing local flow obstructions (e.g., sediment accumulation) to restore interaction between the river and the swamp and increasing freshwater inputs to improve water quality, fisheries health and forest condition.
  • Restore natural flooding and drying cycles in forested wetlands within the floodway and outside the protection levees while working in partnership with flood control and navigation interests.
  • Work with the state of Louisiana, U.S. Army Corps of Engineers, parishes, nongovernmental organizations (NGOs) and private landowners to find common ground for basin management among flood control, commercial/recreational fisheries, navigation, oil and gas, recreational and cultural interests.
  • Monitor wetland vegetation and aquatic invertebrates during spring and fall migration to assess whether food availability needs of migratory birds are being met.
  • Manage oil and gas development on NWRs through comprehensive monitoring and operator coordination to prevent and/or limit the adverse impact of spills and leaks on wetlands and refuge habitats.

Control the extent and density of invasive non-native plant and animal species within the Atchafalaya River Basin to enhance native habitat, navigation and water quality.

Next Steps

Two small aquatic rodents on the edge of a marsh.
Invasive nutria. Photo by Robert Smith,
  • Acquire better information on the distribution and management of hydrilla, salvinia, water hyacinth and other aquatic invasive plants in order to prioritize locations for management actions (e.g., improving water circulation to reduce how invasive plants in ponded areas restrict access to many areas in the basin and exacerbate hypoxic conditions in the swamps).
  • Conduct periodic drawdowns in areas where water levels are controlled or floodplains can be dewatered to manage aquatic invasives such as hydrilla, and install water control structures at sites that provide opportunities for drawdown benefits.
  • Review and update the Integrated Pest and Invasive Species Management Plans to address the habitat needs of NWRs and conservation partners in the basin. Work with landowners adjacent to NWRs and other partners to control non-native Chinese tallow tree and mimosa infestation in bottomland hardwood forest to restore natural wetland habitat conditions.
  • Work with and support efforts of partners and stakeholders throughout the basin to control Asian carp, feral hogs, nutria and other invasive wildlife species that range through the focal area.
  • Restore water management capabilities on NWR moist soil units and greentree reservoirs by improving the outer bank levees, upgrading water management infrastructure and removing invasive plants.

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