USC Citizens for Land Stewardship
Conservation and stewardship of land and natural resources in Upper St. Clair





The Mayview Valley Biological Diversity Area

by Andrew M. Loza

Seemingly few people know that a portion of Upper St. Clair park land has been identified as one of the most significant natural areas in Allegheny County. This “Mayview Valley Biological Diversity Area” is located in the vicinity of the PennDot wetlands, Chartiers Creek, Morton and Mayview Roads. The Mayview Valley Biological Diversity Area-Mayview BDA for short- possesses a rich diversity of plant species. Contrary to expectations, its significance has little to do with the wetlands. Instead its significance derives from the forested slopes and upland areas controlled largely or entirely by Upper St. Clair Township.

Since the Mayview BDA is small, encompassing only 280 acres, its biological richness is threatened by development of any kind. The Allegheny County Natural Heritage Inventory recommends that municipal officials consider allowing park land in the vicinity of the BDA to revert back to forest in order to better protect the biological diversity.

The Allegheny County Natural Heritage Inventory identifies the most significant natural areas in the county. The Inventory made a thorough search for plant and animal species and communities that are unique or uncommon in the County. It also identified areas important for general wildlife habitat, education and scientific study. The Inventory found very few sites of natural significance in the South Hills.  This makes these sites all the more important. The Mayview BDA is one of these few.

The Natural Heritage Inventory was completed in 1994 by the Western Pennsylvania Conservancy under contract with the Allegheny County Planning Department. The enclosed map was prepared by the Allegheny Land Trust to provide an informative, easily readable, low-cost summary of the 299-page inventory. The Inventory does not confer protection on any of the sites listed within. It is instead a tool for informed decision making by landowners, municipalities, conservation organizations, developers and other interested parties.


Mr. Loza is the Executive Director of the Allegheny Land Trust which preserves significant wildlife habitat, farmland, scenic vistas, recreational areas, and other open space. The Trust has a pro-active program to acquire and conserve lands identified as Biological Diversity Areas. It accomplishes this both by accepting land donations and by purchasing lands from willing landowners. The Trust's Dead Man's Hollow Wildlife Preserve at the Liberty Valley BDA is the largest privately protected conservation area in Allegheny County.