Physical Sciences and Mathematics Commons^™

Nestedness And Modularity Of Avian Metacommunities Across Gradients Of Chesapeake Bay Island Characteristics, Grant Walter Bowers

Biological Sciences Theses & Dissertations

Islands are not only great models for understanding the ways in which communities are linked by the dispersal of their members to form metacommunities, but are of particular interest to conservationists. One important aspect of metacommunity structure is the degree of nestedness—whether or not less speciose communities are perfect subsets of more speciose communities. Another important metric of metacommunity structure is modularity—the degree to which communities belong to modules composed of other communities that share the same species but have little species overlap with communities from different modules. Environmental gradients have received insufficient attention as predictors of metacommunity nestedness and …

Identifying Key Stream Restoration Variables In An Agriculturally Impaired Chesapeake Bay Watershed, Julia Portmann

Masters Theses, 2020-current

The Chesapeake Bay watershed spans several states, supports diverse ecosystems, and is crucial to local economies. However, agricultural practices in this region impair water quality. The Smith Creek watershed, within the Shenandoah Valley, was designated a showcase watershed in 2010 by the United States Department of Agriculture to demonstrate the efficacy of implementing restoration projects. We sampled fifteen farms ranging from unrestored to thirty-six years since restoration. At each site, we conducted a kick-net survey for macroinvertebrates, measured canopy cover, algal density, substrate size, and bank height and angle. We identified macroinvertebrates to family and calculated the Chesapeake Basin-wide Index …

Nitrogen Reductions Have Decreased Hypoxia In The Chesapeake Bay: Evidence From Empirical And Numerical Modeling, Luke T. Frankel, Marjorie A.M. Friedrichs, Pierre St-Laurent, Aaron J. Bever, Rom Lipcius, Gopal Bhatt, Gary W. Shenk

VIMS Articles

Seasonal hypoxia is a characteristic feature of the Chesapeake Bay due to anthropogenic nutrient input from agriculture and urbanization throughout the watershed. Although coordinated management efforts since 1985 have reduced nutrient inputs to the Bay, oxygen concentrations at depth in the summer still frequently fail to meet water quality standards that have been set to protect critical estuarine living resources. To quantify the impact of watershed nitrogen reductions on Bay hypoxia during a recent period including both average discharge and extremely wet years (2016–2019), this study employed both statistical and three-dimensional (3-D) numerical modeling analyses. Numerical model results suggest that …

Management Practices For Urban Areas In The Hampton Roads Vicinity: Data Files, Gary F. Anderson

Data

During 1980 through 1981, the Virginia Institute of Marine Science conducted studies in the Hampton Roads Virginia vicinity to assess pollutant loading in runoff from various land use types. The 13 urban study areas also included established BMPs such as grassy swales and retention ponds to measure their effectiveness in reducing pollutant loads to the Chesapeake Bay. The focus was on nutrients, BOD and suspended solids. The studies were conducted with support of the U.S. EPA under section 208 of the Federal Clean Water Act.

Methods and results are documented in the associated publication. Data files were processed using SPSS …