Ecosystems Studies & Management

Understanding Human Impacts on the Chesapeake Bay

Integrated Ecosystem Analyses

Human modification of the land surface has an impact on the health of the Bay.

The land cover maps and predictive modeling results described in the other sections of these web pages are useful for ecosystem analyses and assessments. In many ways they provide a new way of viewing and analyzing the landscape. This capability is particularly important because the causes of impairment of the Chesapeake Bay estuary operate principally on the land and are dispersed over its 168,000 square kilometer watershed. Beyond categorical classification of land cover, the maps of continuous land cover variables (percent impervious and tree cover) permit detection of key features of the landscape, such as low density residential development and the density of tree cover in riparian buffers.

Riparian buffers help protect water quality.

In the case of stream health assessment, these new map products allow consideration of landscape configuration variables that would not have been possible to produce from categorical maps of land cover or county-level statistical summaries. As a result, WHRC scientists can derive refined criteria that can be use to target watersheds, or streams within them, for restoration or protection, as appropriate.

Forests are cleared for new development.

In the case of resource lands loss, the landscape scale analyses aid monitoring efforts required to assess whether land preservation targets are being met across the region and, if not, where the greatest changes are occurring so that adaptive management can be better focused. They also provide key indicators of ecosystem health, or indices of ecological integrity, that are useful for monitoring the changes that occur incrementally, and are thus not often kept in perspective over the longer term (e.g., conversion of forest lands over 20 or 30 years).

Targeted forest management for the Chesapeake Bay.

In the case of vulnerability assessments, the predictive modeling work permits examination of the potential future impact of various policy scenarios and associated land management decisions. It further aids targeting efforts focused on establishing a network of resource lands (particularly forests and wetlands) that best protect water quality, preserve biological diversity, promote sustainable forestry, and enhance the quality of life residents in the region often take for granted.

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