Mid-Atlantic Landscape Atlas
Ecological Assessment of the Mid-Atlantic Region
A Landscape Atlas 1997
The Atlas is an EPA report assessing relative ecological conditions across the mid-Atlantic region of the United States (encompassing Delaware, the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia - see Figure at left). The Atlas identifies, with never-before achieved detail and comparability, patterns of land cover and land use across the region. It presents an ecological snapshot to help the reader visualize and understand the environmental conditions across the region, and how the pattern of conditions can be applied to community-based environmental decision making. The Atlas represents one of the first regional-scale ecological assessments of the Environmental Monitoring and Assessment Program (EMAP), will contribute to comprehensive ecological assessments being conducted by EPA Region III, and will be useful to states, local communities, and others.
The report is based on data from satellite imagery and spatial databases on biophysical features such as soils, elevation, and human population patterns. It compares nine landscape indicators on a watershed-by-watershed basis for the lower 48 states (at a relatively coarse-scale resolution of 1 km), placing the mid-Atlantic region in the context of the rest of the country. Using finer-scale spatial resolution (e.g., 30-90 meters), the report then analyzes and interprets environmental conditions of the 125 watersheds in the mid- Atlantic region based on 33 landscape indicators. Results are presented relative to four general themes identified by stakeholders in the region:
- people (potential human impacts),
- water resources,
- forests (forest habitat), and
- landscape change.
The Atlas compares watersheds using color codings based on the authors' interpretation of "more" vs. "less" desirable ecological conditions. For instance, a high degree of forest cover is rated as more desirable than limited forest cover. The watersheds are ranked relative to each other, not on an absolute scale of ecological desirability. All indicator values are presented for each watershed in an Appendix, so readers can draw their own conclusions.
Major Findings of the Atlas
- The mid-Atlantic has diverse spatial patterns of agriculture and urban lands as compared to other parts of the country (about 10% of the nation's watersheds have been almost completely converted to agricultural land, while about 40% of the nation's watersheds have only small amounts of agriculture, excluding livestock grazing). Mountainous watersheds in the mid-Atlantic region have the least amount of agricultural and urban land cover and coastal areas the greatest.
- Mid-Atlantic watersheds have relatively high (more desirable) values for forests, forest connectivity, and forests near streams (riparian zones) as compared to other parts of the country, especially the Midwest and southwestern United States.
- Six watersheds in the south-central portion of the region along the border with North Carolina, ten watersheds in the southwestern portion of the region, and three watersheds in north-central Pennsylvania have the most desirable landscape conditions based on the suite of landscape indicators. These areas have relatively low values for population, road density, and agriculture, and have the highest amounts of forest and riparian vegetation.
- Nineteen watersheds in the northwestern, northeastern and Norfolk, Virginia areas of the region have the least desirable landscape conditions. These watersheds have high values for population density, road density, agriculture on steep slopes, and sulfate deposition, and low values for riparian vegetation and interior forest indicators. These areas are typically around the major metropolitan areas of Baltimore-Washington, D.C., Pittsburgh, and Norfolk.
- The remaining watersheds fall between the most desirable and least desirable conditions. Some appear to be in a desirable condition relative to one environmental theme, but in a less-desirable condition relative to another. For example, watersheds in the Delmarva Peninsula are in better relative condition from a water quality perspective, but provide little interior forest habitat. Conversely, several watersheds throughout the Ridge-and-Valley and Appalachian Plateau areas have the opposite pattern, with relatively more interior forest habitat but less-desirable conditions for water-related indicators (such as the amount of crop land on steep slopes).
Comparison of the Atlas to EPA's Index of Watershed Indicators
In October 1997, EPA issued its first Index of Watershed Indicators report. The Index and the Atlas have some similarities and share some underlying data, but there also are important differences. The Atlas examines both water conditions and non-aquatic resources (such as forest condition), whereas the Index focuses on aquatic resources; the Atlas emphasizes the mid-Atlantic rather than presenting a national assessment; and, unlike the Atlas, the Index incorporates information from direct water quality monitoring. Future editions of the Index may adopt some of the approaches developed for the Atlas.
Obtaining the Atlas and its Datasets
To order copies of An Ecological Assessment of the United States Mid-Atlantic Region: A Landscape Atlas, publication no. EPA/600/R-97/130, call EPA's Center for Environmental Research Information at (513) 569-7562. An electronic version of the Atlas is available from this World Wide Web site as are the underlying datasets. An abstract, index, and information about obtaining a CD-ROM version or the underlying datasets (expected to be accessible in Fall 1998) will be made available through the website of the National Exposure Research Laboratory (NERL) Las Vegas at http://www.epa.gov/nerlesd1/.