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Title: Habitat development field investigations, Windmill Point marsh development site, James River, Virginia ; Appendix D: Environmental impacts of marsh development with dredged material: Botany, soils, aquatic biology, and wildlife
Authors: Virginia Institute of Marine Science
Keywords: Constructed wetlands
Dredging spoil
Dredged material
James River (Va.)
Wildlife habitat improvement
Dredged Material Research Program (U.S.)
Publisher: U.S. Army Engineer Waterways Experiment Station
Series/Report no.: Technical Report (Dredged Material Research Program (U.S.)) ; no. Technical Report D-77-23; Appendix D
Abstract: A marsh island habitat was constructed in the James River between November 1974 and February 1975 from fine-grained dredged material partially contained by a sand dike. The marsh-island contained 4.9 ha of intertidal and low-lying upland substrate within the dike and an intertidal mudflat outside the dike. Benthic invertebrates, fish, wildlife (particularly birds), plants and soil characteristics of the habitat development site were studied from summer 1976 to fall 1977. Between the completion of site construction and the beginning of ecological studies, the island was sprigged and seeded with wetland and upland vegetation. The majority of the planted wetland species were grazed and destroyed by wildlife (particularly Canada geese); most of the upland seeded species were displaced by native plant invasion. Compared with adjacent open-water and shallow river bottom habitats, the marsh island was characterized by increased species abundance, diversities and biomass. Compared with nearby natural marshes and low-lying upland sites chosen as reference areas, the habitat development site produced a greater abundance and biomass of a less diverse benthos, a similar abundance and biomass of a less diverse fish community and an increased abundance of a less diverse bird community. The habitat development site's stable arrowhead-pickerelweed and beggar tick plant communities exhibited normal seasonal changes along with an upland-plant community undergoing succession to more woody vegetation. Differences in soil and physical characteristics probably accounted for most of the differences between the habitat development and reference sites. If the marsh island is not destroyed by continuing erosion, the differences in soil characteristics will probably decrease with time and similarity in the biological community characteristics may increase. The marsh island habitat development was beneficial to the region with respect to biological resources by providing an increase in both food and cover for fish and wildlife relative to the original shallow river bottom. The developed habitat compared favorably with natural reference areas in terms of fish and wildlife resources and productivity. The major threat to the island is severe erosion of its upstream end. Continuous erosion would expose the fine-grained interior of the marsh island to the energies of the mainstream James River.
Description: Technical Report
Gov't Doc #: Technical Report D-77-23; Appendix D
Rights: Approved for Public Release; Distribution is Unlimited
Appears in Collections:Technical Report

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