Abstract
Gulf of Mexico coastal wetlands support millions of migratory birds annually. However, between 2004 and 2009, Gulf states have experienced 71% of the total decline of coastal wetlands within the conterminous United States with Louisiana accounting for most of this loss. Marsh terracing is one method used to combat coastal wetland loss. This restoration technique uses in situ sediment to construct segmented ridges in open water areas of shallow coastal wetlands to dissipate erosive wave energy, reduce turbidity, increase submerged aquatic vegetation production, and create habitat for a diversity of avian species. Despite widespread use of marsh terraces in coastal restoration, research on their value as bird habitat is limited and inconclusive. Using both ground and aerial surveys, our study evaluates avian use of marsh terraces across multiple paired sites (terraced and non-terraced) in coastal Louisiana. Surveys focused on two guilds of birds: breeding secretive marsh birds and wintering waterfowl. Preliminary results from our first field season indicated: 1) terraced sites were used predominately by non-focal species such as red-winged blackbirds, 2) low use of terraced sites by focal marsh bird species, 3) and generally low use of terraced and non-terraced sites by wintering waterfowl, although species abundances varied in space and time. Field efforts are ongoing, and data collection will be completed by July 2021. Future analysis will examine relationship between avian use and habitat characteristics of study sties (e.g., submerged aquatic vegetation, diversity and structure of emergent vegetation). Marsh complexes throughout the Gulf region, including the “Biloxi” marshes in southeastern Louisiana and southwestern Mississippi, continue to experience significant marsh loss. Our results will better inform decisions on restoration techniques used to minimize marsh loss and improve bird habitat at local and regional scales.
