Differences in the avian communities of natural and created Spartina alterniflora salt marshes

Birds were surveyed by censusing strip transects monthly from October 1990 through September 1991 in seven created and seven natural salt marshes located in lower Galveston Bay. All birds observed using the transect, the airspace above the transect, and 5m of bay bottom adjacent to the transect were recorded. Species richness and species diversity were calculated for each salt marsh and compared between natural and created sites. Species richness and diversity were greater in natural salt marshes due to the occurrence of migratory waterfowl, wintering shorebirds, and typical marsh species such as rails and marsh sparrows. Birds using created salt marshes consisted primarily of gulls and terns, especially during the nesting season. Bird density was greater in natural marshes during fall and winter months, while created marshes had higher bird density from March through July. Created salt marshes provided bird habitat, however not necessarily for the same species assemblage as natural salt marshes.