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Research about Atchafalaya Basin

Source-linked reports with geographic coverage including Atchafalaya Basin.

5 recordsLinked to original sources
USGS2011

Amphibian monitoring in the Atchafalaya Basin

Amphibians are a diverse group of animals that includes frogs, toads, and salamanders. They are adapted to living in a variety of habitats, but most require water for at least one life stage. Amphibians have recently become a worldwide conservation concern because of declines and extinctions even in remote protected areas previously thought to be safe from the pressures of habitat loss and degradation. Amphibians are an important part of ecosystem dynamics because they can be quite abundant and serve both as a predator of smaller organisms and as prey to a suite of vertebrate predators. Their permeable skin and aquatic life history also make them useful as indicators of ecosystem health. Since 2002, the U.S. Geological Survey has been studying the frog and toad species inhabiting the Atchafalaya Basin to monitor for population declines and to better understand how the species are potentially affected by disease, environmental contaminants, and climate change.

Louisiana↗
USGS2009

Identifying baldcypress-water tupelo regeneration classes in forested wetlands of the Atchafalaya Basin, Louisiana

Baldcypress-water tupelo (cypress-tupelo) swamps are critically important coastal forested wetlands found throughout the southeastern U.S. The long-term survival and sustainability of these swamp forests is unknown due to large-scale changes in hydrologic regimes that prevent natural regeneration following logging or mortality. We used NWI wetland maps and remotely sensed hydrologic data to map cypress-tupelo communities, surface water, and the extent and location of proposed regeneration condition classes for cypress-tupelo swamps in the Atchafalaya Basin, LA. Only 6,175 ha (5.8%) of the 106,227 ha of cypress-tupelo forest in the Lower Atchafalaya Basin Floodway was classified as capable of naturally regenerating. Over 23% (24,525 ha) of the forest area was mapped as unable to regenerate either naturally or artificially. The loss and conversion of nearly 25,000 ha of cypress-tupelo forest would have significant and long-lasting impacts on ecosystem services such as wildlife habitat for birds and Louisiana black bears. Given the landscape-scale changes in surface elevations and flooding depths and durations throughout southern Louisiana, similar conditions and impacts are likely applicable to all coastal cypress-tupelo forests in Louisiana. Better data on flooding during the growing season are needed to more accurately identify and refine the location and spatial extent of the regeneration condition classes.

Louisiana↗
USGS2008

Conveying multiple, complex themes and classes for natural resource assessments

Two methods were used to convey the spatial association between a classified forested landscape, the distribution of a hurricane impact, and the subsequent recovery of the habitat from the storm. The first method used a constant hue matrix with varying intensity to visually represent combinations of impact and recovery magnitudes. The second combined two colors of constant hue to represent the impact and recovery succession. Maps produced using either method generally simulated known impact and recovery spatial distributions. In the constant hue representation with varying intensity, the combination of impact and recovery could not be uniquely represented in all cases and the relationship was confused between the map and legend color. In the two color representation, however, a definite link existed between the map and legend color and the impact and recovery magnitudes. A drawback to this approach over the constant hue approach was that a separate map had to be used to represent each forest type and its associated impact and recovery covariation. The two color combination, however, provided improved contrast and uniquely defined the link between map and legend colors, and ultimately, a unique impact and recovery combination. In addition, the two color combination produced the highest conveyance of spatial information related to the covariation of forest type, impact, and recovery.

Louisiana↗
USGS1995

Structural impact of hurricane Andrew on the forested wetlands of the Atchaflaya Basin in South Louisiana

On August 26, 1992, Hurricane Andrew hit the Louisiana coast and traversed a large portion of the lower Atchafalaya Basin, bounding the largest remaining tract of cypress-tupelo and bottomland hardwood swamp in the United States. Permanent field sites were established following the hurricane to assess the extent of forest damage and to monitor the rate and process of forest recovery. Bottomland hardwood forests had significantly greater damage and mortality than did cypress-tupelo communities. Canopy trees suffered the greatest direct damage, particularly in sites within the storm's eyewall and right quadrant. The type and extent of damage (windthrow, branch loss, and defoliation) generally decreased as distance from the storm path increased. Azimuths of downed trees were strongly correlated with predicted wind vectors derived from a hurricane simulation model of Andrew. Species differences were readily apparent, indicating a high degree of tolerance to windthrow by baldcypress and water tupelo, and intolerance by many common hardwood species. Bottomland hardwood forests are particularly susceptible to catastrophic disturbance by hurricanes such as Andrew, which have significant impact on forest structure and dynamics.

Louisiana↗