Wildflower is published quarterly by the Wildflower Center. Its content is national in scope with articles about the conservation and use of native plants as well as news from the Wildflower Center. A subscription is provided to Wildflower Center members as a benefit of membership.
Each spring, as migrating warblers, grosbeaks and other songbirds are feeding in trees at Ryerson Woods in northeastern Illinois, Joan Palincsar is bent over pulling garlic mustard (Alliaria petiolata) from the forest floor. Palinscar pulls the shallow-rooted, flimsy, 8-inch tall plant from the soil, before it goes to seed and has the chance to spread. By the end of the spring season, Palinscar and other volunteers have filled dozens of large garbage bags with the non-native plant that threatens to choke out the native ones and disturb the diversity of a native woodlands, designated as an Illinois Nature Preserve.
Palincsar is among a growing number of individuals, local and national conservation organizations, university research departments, the National Park Service, and state and county natural resource departments, working to keep non-native plants from drastically disturbing the native wetlands, woods and grassland ecosystems of North America.
Known as aliens, non-natives, noxious plants, or weeds, these plants all have something in common - they are growing in an ecosystem where they don't belong. And because they are growing without their natural insect pests and plant diseases to keep them in check, they can crowd out native plants, and in turn harm other species that rely on these native plants for food, shelter, and breeding grounds.
The proliferation of non-native species is one of the second largest threats to biodiversity in the United States, second only to habitat destruction, according to "Precious Heritage: The Status of Biodiversity in the United States," published by the Nature Conservancy in 2000.
"The estimate is that 50 to 70 percent of our native species including plants and animals are in peril due to encroachment from non-native species," says James H. Miller, a research ecologist with the USDA Forest Service, who works at the southern research station in Alabama.
As of the year 2000, the U.S. Department of Agriculture has placed more than 100 plants on the Federal Noxious Weed List. Where did all these plants come from and why are they causing problems for the native ecosystems of North America?