Trends and causes of historical wetland loss in coastal Louisiana

The Mississippi River delta plain was constructed from fluvial sediments that were deposited in overlapping delta lobes. Thick peat deposits that accumulated in interdistributary areas underlie the modern delta-plain wetlands. In comparison, the chenier plain was constructed by the alongshore progradation of broad mudflats capped by thin peat deposits and wetland vegetation with intervening narrow, sandy beach ridges (cheniers). The 10 delta-plain study areas encompassed several different physiographic settings, including (1) an upper deltaplain levee flank of the Mississippi River, (2) a preexisting upper delta-plain interior channel, (3) four upper delta-plain interdistributary areas, (4) three lower delta-plain interdistributary areas, and (5) a lower delta-plain beach-ridge margin area. The six western chenier-plain study areas were located in Sabine National Wildlife Refuge (SNWR), which occupies a broad, shore-parallel, low-lying area that formed between the higher elevation beach ridges along the gulf shoreline to the south and upland areas to the north. Historical Wetland Loss