FY2005 Task 9.02
College of William and Mary-Center for Conservation Biology
Assessing the Potential Impact of Common Reed Expansion on Threatened High-marsh Bird Communities along the Delmarva Seaside:
Phase II (Breeding Bird Surveys of Selected High-marsh Patches)
Project Description as Proposed:
Many bird species that utilize high marsh habitats have experienced population declines within recent history. One of the primary causes of these population declines is habitat loss. While direct human influence (development) is the leading cause of habitat loss, factors such as sea level rise and invasive exotic species also alter available habitat. Surveys of breeding birds within high marsh patches, with and without Common Reed, will be conducted to determine if, and to what extent, the expansion of Common Reed is having an effect on the diversity and density of the high marsh bird community.
Surveys of breeding birds will be conducted within selected high marsh patches of the Northampton and Accomack county seaside. A sub sample of available patches will be selected based upon size, vegetation cover, position, and degree of Common Reed invasion. Breeding bird surveys will be conducted at all patches three times during the breeding season (late May to late July). Species richness values and breeding bird densities (particularly those with high conservation status) will be used to determine the effect of Common Reed expansion upon the high marsh bird community.
Bryan E. Watts, 804.698-4323; firstname.lastname@example.org
Final Product Received:
Potential Impact of Common Reed Expansion on Threatened High-marsh Bird Communities on the Seaside: Breeding Bird Surveys of Selected High-marsh Patches - PDF
Project Summary Provided by Grantee:
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 a site 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 activities are still a leading cause of wetland loss, the structure and functioning of high marsh habitats are currently threatened from invasion of exotic and/or invasive plant species such as the common reed (Phragmites australis
), and sea level rise due to global climatic change. Disturbance of habitat from dredging, filling, ditching, draining, and clearing, as well as the introduction of more invasive genotypes from the Old World, has enabled P. australis
to invade habitats where it was once absent.
Stands of P. australis are considered poor wildlife habitat and large, monocultures of Phragmites offer little habitat for birds and support few individuals and low diversity. The high marsh habitats, which provide breeding habitat for several avian species of concern, including Saltmarsh Sharp-tailed Sparrows, Seaside Sparrows, Black Rails, and Willets, are most at risk from invasive P. australis.
Eighty 250-m transects were established within 40 high-marsh sites on the Delmarva Peninsula of Virginia. All study sites were established in marsh complexes with at least 5 hectares of high-marsh habitat and were selected to include marsh patches along the gradient of P. australis invasion and latitudinal position on the peninsula.
A total of 87,500 m of transects were surveyed, resulting in 2,950 detections of 81 species. The most commonly detected species were Red-winged Blackbirds, Willets, Seaside Sparrows, Common Yellowthroats, and Sharp-tailed Sparrows. Two of these species, the Seaside Sparrow and Sharp-tailed Sparrow, are species of high conservation concern. Seaside and Sharp-tailed Sparrows were found in significant numbers within large high-marsh patches on the northern portion of Virginia Delmarva Peninsula, regardless of P. australis presence. However these species rarely, if ever, utilized P. australis, and still required large patches of high-marsh grass and high-marsh shrub habitat.
Disclaimer: This project summary provides the federal dollars initially awarded to the grantee. Due to underexpenditure or reprogramming of grant funds, this figure may change. For more information on the allocation of coastal grant funds, please contact Laura McKay, Virginia Coastal Program Manager, at 804.698.4323 or email: Laura.McKay@deq.virginia.gov
A more detailed Scope of Work for this project is available. Please direct your request for a copy to Virginia.Witmer@deq.virginia.gov