Restoration and expansion of research by the Federal Government, including the US Department of Agriculture, on host specific biological controls of Lesser Celandine and other non- native invasive species is crucial to our economic and environmental future. The US Department of Agriculture and other agencies and Universities have already completed some research on this subject for Japanese Stiltgrass and other non-native species in the Mid-Atlantic region. it is important that research is expanded to combat other non-native invasive species. This is necessary to ensure the well-being of our native plant and animal species. We need continued research on species such as Wavyleaf Basketgrass, Lesser Celandine and Kudzu as they continue to take over our national forests and parks. Lesser Celandine especially could become a human health threat as it has been shown to increase the risk of storm water runoff and water pollution in damp or wet areas.
Our tool kit for successful control of non-native invasive plants includes preventing new invasive species from coming in from Europe, Asia, and other continents, manual removal, the use of carefully targeted herbicides, and host specific biological controls. Non-native invasive plants are covering all our natural areas in the region. The quantity of native plants and animals replaced by competition with non-native species is greater than that lost from all other causes except direct development in our terrestrial habitats and water pollution in our aquatic habitats. Non-native invasive species of plants such as English Ivy, Japanese Stiltgrass and Kudzu are covering the natural areas that we in the conservation movement have worked so hard to protect from habitat destruction, erosion and water pollution.
Just as we are making progress on wetlands, stream bank stabilization, and endangered species, these plants from other parts of the world have typically covered 20-90% of the surface area of our forests, streams and meadows. Many of us feel demoralized and powerless to combat these invaders that have few natural herbivores or other controls. A typical park is 50-500 acres and has over a hundred species of native plants let alone the hundreds of native species of insects, mushrooms, snails, reptiles, mammals and birds that depend upon the plants prior to being covered by monocultures of 5-10 alien species.
One of our most productive activities to save our natural areas is to facilitate research that will make host specific biological controls available. Insects that consume the non-native invasive plant species can substitute for the controls where the species came from in the world. Of the 15 top non-native invasive plant species in the mid-Atlantic region three (Purple Loosestrife, Mile-a-minute and Garlic Mustard) now have one or two non-native insects or fungi that feed on them although the permit request for garlic mustard has not been approved yet. They were brought over after being tested for host specificity in Eurasia and then tested in quarantine conditions in the United States. Typically, about 50 such bio-control agents control these species in their native countries so if one or two can control them here that is amazing. In actuality, bio-controls work about half the time reducing the invasive species to about 10% of its former abundance. The problem of bio-controls harming non-target organisms is only about 3% as frequent as before the new rules of proving host specificity went into affect about 20 years ago. Native and indigenous biocontrols are also searched for in the range of the non-native invasive species in America.
Success stories include a native viral pathogen (rose-rosette disease), which is spread by a tiny native mite, Rose-rosette disease, native to the western U.S., that has been spreading eastward at a slow pace and is thought to hold the potential for eliminating multiflora rose in areas where it grows in dense patches. Tree of Heaven is an invasive non-native plant and is considered one of the top ten weeds in North America for about 200 years. A law passed in the 19th century makes it illegal to plant it in Washington, DC. A mixture of field and laboratory research shows that native and indigenous bio-controls from the new Southern part of the range are available. The insects consist of Aculops ailanthii and Atteva punctella with various fusarium fungi co-hosts. Cheatgrass "has fueled almost 80% of the largest fires in the west over the last ten years. Researchers are looking at a range of solutions including using a fungus to attack the grass seed. " This is an example of the need for research for bio-controls; Let's do the same for our invasive Lesser Celandine in the North.
Lesser Celandine has destroyed much of our natural environment in our region according to the surveys done by the National Park Service and other agencies. We have been removing it at many of our preservation sites so that native plants, and the animals that depend on them, can recolonize in infested areas once a native or host specific non-native biological control arrives.