Bird surveys of Lee and Hill Marshes on the Pamunkey River: Possible affects of sea-level rise on marsh bird communities
Tidal wetlands are important to coastal ecosystems. They provide flood protection, erosion control and improve water quality. Tidal wetlands also provide essential habitats for numerous species of wildlife, many of which rely on these marsh habitats as sites for breeding and development. Historical wetland surveys indicate that as much as half of the marshes present along the Atlantic and gulf coasts in 1900 have disappeared. While direct human impact has long been a cause of wetland loss, sea level rise is quickly becoming a leading source of current and anticipated wetland losses. Brackish marshes, situated on the transition zone between tidal freshwater and oligohaline marshes, may be most at risk from the effects of sea level rise. Lee and Hill marshes, located near the mouth of the Pamunkey River, are two of the largest brackish marshes remaining in Virginia. Due to the isolated and inaccessible nature of many brackish marshes within the Chesapeake Bay, little information exists on their associated bird communities. The objectives of this study were to provide information on the species presence, distribution, and abundance of birds within Lee and Hill marshes during the breeding and winter season. An additional objective was to quantify the relationship between birds and the dominant vegetation types within these marshes. Thirty-two survey points were established within Lee and Hill Marshes and associated with one of three habitat types (Peltandra mix, Spartina cynosuroides, and Phragmites sp.). Birds were surveyed 3 times at each point during the breeding season of 2001, and 3 times during the late winter of 2002. Results from surveys were used to calculate species richness and density estimates for habitat types. A total of 3,510 detections of 38 species were made during both survey seasons within all habitat types. During the summer surveys 1,711 observations were made of 19 species. Winter surveys resulted in 1,799 detections of 26 species. Some differences were noted in species richness values and densities between habitat types. This information will be useful in monitoring and projecting changes in the bird populations of these marshes in the event of changes to the vegetation community due to sea level rise or other factors.