Coastal wetland vegetation assessment data collected to characterize marsh vegetative communities throughout coastal Louisiana, Mississippi, and Alabama from Fall 2010 to Fall 2013

This report contains coastal wetland vegetation assessment data, and provides additional context for the posted dataset, including information about the collection, analysis, and organization of the data. Characteristics of this dataset include the following: The coastal wetland vegetation assessment data characterize the marsh vegetative community at multiple points in space and time. This dataset consists of data collected cooperatively with the Trustees. Before posting, extensive work was done independently by BP contractors to verify some aspects of the posted data (e.g., positional coordinates and field data). The focus of this data posting is coastal wetland vegetation assessment data collected to characterize marsh vegetative communities at 202 sites throughout coastal Louisiana (164 sites including 14 sites established in Barataria Bay), Mississippi (22 sites), and Alabama (16 sites). Data collection was initially conducted in Fall 2010 at 150 of the 164 sites in Louisiana and in Spring 2011 at all of the previously established 150 Louisiana sites, the 14 remaining sites in Louisiana (Barataria Bay) as well as all of the sites in Alabama and Mississippi. During fall 2011, fall 2012, and fall 2013, monitoring was repeated at all 202 sites. The data were collected under the work plan titled Sampling and Monitoring Plan for the Assessment of MC252 Oil Impacts to Coastal Wetland Vegetation in the Gulf of Mexico, including three addenda. The work plan was cooperatively developed and implemented as part of the NRDA for the DWH Horizon accident. This dataset includes data associated with field observations: Visual estimates and counts of vegetative conditions Instrument-based measurements of environmental conditions (e.g., reduction-oxidation potential [REDOX], light-adapted fluorescence [LAF], and chlorophyll content [CC]) Vegetation and sediment sampling (biomass and nutrient data1) Soil condition data Sampling variations may exist across observers, methods, locations, and times. For example, erosion and site flooding occasionally limited or completely inhibited sampling so only a portion of or no data could be collected.