FT 6

Vegetation, Flora, and Ecology of the Potomac Gorge

The Potomac River has shaped the land along its place on the Atlantic coast Fall Line for millennia. During the Pleistocene, falling sea levels increased the river's gradient, allowing it to carve the dramatic Potomac Gorge. This gradient also generates high velocity currents during major floods, which scour riparian surfaces to near bedrock and create globally rare plant communities, such as riverside prairies and bedrock terrace forests. Some of the highest vascular plant species richness counts recorded in the United States occur here. In a trip that includes Virginia, Maryland, and the District of Columbia, we will examine these and other community types and learn about their contribution to and place in to the U.S. National Vegetation Classification. We also will encounter a number of locally rare and disjunct plant species. While the trip will focus on vegetation and flora, we also will see a number of historical structures from the American canal building era and the unusual and scenic fall line geomorphology features, such as the Great Falls of the Potomac and the many outdoor opportunities such as hiking, bicycling, whitewater boating that attract millions of recreational enthusiasts to this area every year.

Among the trip leaders are biologists who represent the two national parks that manage this globally significant natural resource, as well as the Nature Conservancy. They will discuss the work of protecting these elements of the nation's natural, cultural, and scenic heritage within the urbanzed landscape of the Washington, DC metropolitan area. Invasive plant species, high deer populations, municipal water withdrawals, urban temperature influences, and nitrogen deposition are among the challenges.