Implications of Coastal Wetland Management to Nonbreeding Waterbirds in Texas

Texas coastal marshes have declined in number and quality, prompting the widespread use of levees and water control structures to create or enhance coastal marsh habitat. In particular, management techniques that control water to provide fresh (< 0.5 ppt) and intermediate (0.5-5 ppt) marsh in a landscape dominated by brackish and saline marsh. However, research is needed to assess the effectiveness of these techniques in providing waterbird habitat. During 2007-09 along the central Texas Coast, we investigated the effects of marsh management on bird, plant, and aquatic invertebrate communities by comparing leveed areas within the coastal marsh that received water level and mechanical management, to adjacent nonmanaged marsh that received no hydrologic or mechanical manipulations. Managed marshes supported more bird species, greater waterbird densities, greater plant diversity, and greater aquatic invertebrate biomass than nonmanaged sites. However, nonmanaged wetlands supported greater densities and more species of secretive marsh birds (e.g., rails). Management of coastal marsh that reduces water salinities and suppresses plant succession appears to be a possible way to mitigate the effects of declines in fresh and intermediate marsh on nonbreeding waterbirds.