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Research about Chenier Plain

Source-linked reports with geographic coverage including Chenier Plain.

5 recordsLinked to original sources
USGS2022

Chenier Plain region bathymetric and topographic datasets: Methodology report

The goal of the Louisiana Barrier Island Comprehensive Monitoring (BICM) program is to provide long-term data on coastal Louisiana for monitoring change and assisting in coastal management. This study (carried out under Coastal Protection and Restoration Authority contract number 2000339324, BICM2—Chenier TopoBathy DEM) builds upon the previous BICM physical assessment of the Chenier Plain region using bathymetric data from three periods (1930, 2007, and 2017) to develop digital elevation models for historical and current periods. In addition to bathymetric datasets, the study includes light detection and ranging elevation measurements along the coastline to produce elevation datasets for the 2007 and 2017 periods. This report describes the methods used to acquire, process, and produce these products.

Louisiana↗
USGS2012

Recent wetland land loss due to hurricanes: Improved estimates based upon multiple source images

The objective of this study was to provide a moderate resolution 30-m fractional water map of the Chenier Plain for 2003, 2006 and 2009 by using information contained in high-resolution satellite imagery of a subset of the study area. Indices and transforms pertaining to vegetation and water were created using the high-resolution imagery, and a threshold was applied to obtain a categorical land/water map. The high-resolution data was used to train a decision-tree classifier to estimate percent water in a lower resolution (Landsat) image. Two new water indices based on the tasseled cap transformation were proposed for IKONOS imagery in wetland environments and more than 700 input parameter combinations were considered for each Landsat image classified. Final selection and thresholding of the resulting percent water maps involved over 5,000 unambiguous classified random points using corresponding 1-m resolution aerial photographs, and a statistical optimization procedure to determine the threshold at which the maximum Kappa coefficient occurs. Each selected dataset has a Kappa coefficient, percent correctly classified (PCC) water, land and total greater than 90%. An accuracy assessment using 1,000 independent random points was performed. Using the validation points, the PCC values decreased to around 90%. The time series change analysis indicated that due to Hurricane Rita, the study area lost 6.5% of marsh area, and transient changes were less than 3% for either land or water. Hurricane Ike resulted in an additional 8% land loss, although not enough time has passed to discriminate between persistent and transient changes.

Louisana↗
USGS2000

Disruption and restoration of en route habitat, a case study: The Chenier Plain

Cheniers (relict beach ridges) and other habitats adjacent to ecological barriers may be critical linkages in the migratory pathways of long-distance migratory birds. It is important that these wooded habitats provide enough food and cover at the right time to support these birds’ requirements. To date, little attention has been given to the conservation of coastal woodlands, habitats in which en route migrants tend to concentrate in large numbers during migration. Because about one-third of North Americas ’ human population lives within 80 km of the coast, many forest-dwelling landbird migrants now depend on degraded native woodlands and urbanized environments for survival during migration. Restoration or rehabilitation of coastal woodlands, such as the cheniers of southwest Louisiana and southeast Texas, is of particular importance because of historic anthropogenic modifications, their limited geographic extent, and the extraordinary abundance and species richness of migratory birds using them during migration. In this paper, we use the Chenier Plain as a case study to discuss the issue of land use changes and their consequences for maintaining suitable stopover habitat. Results from an ongoing field study in this ecosystem indicate that most forest-dependent migratory birds are tolerant of at least some degradation of chenier forest during migration. However, these results reveal that subtle differences in vegetation composition and structure beneath the canopy of these forests, primarily as a result of livestock grazing and white-tailed deer overbrowsing, can result in differential use by some en route migrants. Species that were most affected by disturbance to the forest understory were early-arriving migrants, dead-leaf foragers, frugivores, and nectarivores. Given that the understory structure and regeneration of chenier forests has been so greatly reduced, and that high densities of nearctic-neotropical migrants tend to concentrate in cheniers during migration, restoration and re-habilitation should be conservation priorities in the Chenier Plain.

Louisiana, Texas↗