Grasslands, natural communities dominated by grass species, are of wide-ranging character and distribution in Virginia. From barrier island dunes to mountain balds, grasslands occupy unusual places in our landscape. Some of these places are unique because of harsh or extreme environmental conditions. Examples include tidally influenced salt waters behind the barrier islands where extensive saltmarsh and saltmeadow cordgrass communities thrive; dry, sunbaked southwestern slopes of mountains; and diabase glades, which have very shallow soils. These conditions thwart woody species and allow sun-loving grasses and herbs to flourish. Grasslands also arise where disturbance, such as drought, flood, or fire has removed woody overstory species. These types of disturbance-dependant grasslands are sometimes called successional grasslands, and are inevitably replaced by shrubs and trees unless maintained by a regular cycle of disturbance.
This brochure focuses on successional grasslands. Successional grasslands and closely related savannas were once much more common in Virginia. Savannas are open-canopy woodlands with a grass-dominated herb layer. Natural grasslands and savannas were maintained by lightening-set fires and human-set fires. Native Americans used fire routinely to clear land for agriculture and to enhance habitat for game. Fires were also used to drive deer toward waiting hunters. Early European settlers adopted the practice of clearing land with fire. In the last 100 years, fire suppression became policy and practice. Technical and organizational advances increased the success of suppression efforts. During the 20th century, fire dependant natural communities such as grasslands, savannas, seepage bogs, pocosins, and longleaf pine forests have all decreased dramatically. Many rare plant and animal species are associated with these communities. Michaux's sumac is a federally endangered shrub found only in fire maintained savannas. Henslow's sparrow, listed as state threatened in Virginia, depends on grassland and savanna habitat for survival.
Today, the best occurrences of successional grasslands and savannas in Virginia are found in and around the artillery impact areas on three military bases: Quantico, Fort A.P. Hill, and Fort Pickett. The regular fires ignited by artillery maintain the grasslands and savannas. Grasslands and bogs become established in another human-created niche, power-line rights-of-way. Mowing and herbiciding by power companies to control woody plants favor the sun-loving grasses and bog species. Many rare species and several rare plant communities are found in power-line rights-of-way.
The six plant species that dominate most of our upland successional grasslands are sod-forming species called warm-season grasses. Big bluestem, little bluestem, bushy bluestem, broomsedge, Indian grass, and switchgrass all have their growing season in the summer months. Many alien grass species introduced to the New World for livestock, such as tall fescue, are cool-season grasses. The warm-season species were also the dominant grasses in the prairies of the Midwest and Great Plains. The drier climate of those regions favors grasslands, whereas the moist climate of the East favors the development of forests.
Along with the grasses, many wildflower species are part of the grassland community. Among these are a variety of species in the aster, pea, and rose families. Common are black-eyed Susan, evening primrose, and butterfly weed. Rare plant species which are found in and adjacent to grasslands include prairie white-fringed orchid, sun-facing coneflower, and running glade clover.
In wet areas such as seepages, pond edges, and stream banks, hydric species take over from upland species. Hydric species are adapted to higher levels of soil moisture than upland species. Sedges and rushes are often more prevalent than grasses. Soft rush, tussock sedge, gama grass, cattail, blue flag, and swamp milkweed are but a few species that may be found in wet areas that receive full sun. For more information on wetland species, see the DCR brochure Native Plants for Conservation, Restoration, and Landscaping -- Riparian Forest Buffers.