Go Native: Avoid Invasive Alien Plant Species
(Conservation Currents, Northern Virginia Soil and Water Conservation District)
Alien plants, also known as exotic or nonnative species, were intentionally or inadvertently introduced usually, but not always, by human activity into a region in which they did not evolve. In North America, plant species are generally described as native if they occurred here prior to European settlement. Some may have been introduced for horticultural purposes. Others arrived accidentally in seed mixes, packaging materials, ship ballast, and even on the shoes of international travelers. Within the United States, a plant native to one area may be carried to another part of the country and be labeled an alien species.
Native species are those that do occur in the region in which they evolved. They possess characteristics that make them uniquely adapted to local environmental conditions. Natives maintain or improve soil fertility, reduce erosion, and often require less fertilizer and pesticides than alien species.
Invasive alien plants threaten biodiversity. Biodiversity refers to the variety of all living things and their interconnectedness. As a general rule, the more biodiverse an ecosystem is, the healthier it is. Less diverse ecosystems are more fragile and less resilient in the face of threats like the introduction of new species. Without natural controls such as insect pests and competitors, some alien plants easily can become established in new areas. Once established, the alien plant species can out-compete and displace the native plant species, disrupting ecological processes and significantly degrading entire plant communities.
Take a ride south on I-95 and you will see kudzu, a fast growing vine that is blanketing the landscape, choking off trees and dependent wildlife in its path. Here in Fairfax County, invasive oriental bittersweet grows along I-66 from Arlington to Fairfax. Mile-a-minute plagues our stream valleys. Garlic mustard threatens wooded areas. And phragmites runs rampant in wet areas such as ponds and drainage ditches.
All plants are native to some region and offer a variety of ecological, economic, and aesthetic benefits. It is only when a species is out of place that we should become concerned. Like a wildfire, invasive plants can seriously damage native plant and animal communities, increase soil erosion and sedimentation, and interfere with outdoor recreation. However, unlike wildfire damage, which soon heals, the effects of plant invasions can be long lasting. As biological pollutants, invasive plant populations can grow, adapt, multiply, and spread to unmanageable levels over time.
How can you help? Use native plant species grown from local stock for conservation and landscaping purposes whenever possible. If you do use alien plants, avoid highly invasive species. The Virginia Department of Conservation and Recreation in partnership with the Virginia Native Plant Society provides a comprehensive list of plant species native to Virginia.
Learn more at www.dcr.state.va.us/dnh/native.htm .