RESOURCES MANAGEMENT FACTSHEET
Invasive Plants
November 14, 2005

What are "Invasive Plants"?
Invasive plant species are exotic plants which tend to crowd out native plants and decrease the number and variety of native plants which inhabit an area. Invasive plants have been brought to North America from other continents for use in agriculture, gardening, erosion control, and medicine, or simply by accident. Invasive plants have the following characteristics: they reproduce rapidly; spread over large areas of the landscape; and have few, if any, natural controls such as herbivores, insects, and diseases to keep them in check. These plants displace native plants and may disrupt the local balance of nature. For example, Japanese honeysuckle may crowd out ash tree seedlings in a given area, eliminating future songbird habitat.

Which plants are considered invasive in Cuyahoga Valley National Park?
Currently, there are 16 plants that are considered to be invasive within the park. These plants invade a broad range of habitats, from pristine forest to disturbed roadsides, from meadows to wetlands.

Are all non-native species harmful?
No. Not all non-native plants are invasive. Many non-native plants have integrated well into the park's ecosystems and pose no threat to the native plant communities. Examples of harmless non-native plants are: chicory, dandelion, curly dock, speedwell, and timothy.

Why is the national park controlling invasive plants?
The ultimate goal of the park with respect to its vegetation is to have naturally functioning plant communities in natural areas of the park. We control invasive plants when their presence menaces these natural conditions. Invasive plants crowd out natives, decrease plant diversity, provide lower quality habitat to wildlife, change soil and water chemistry, and can influence the mix of other species growing in their vicinity. For example, a number of algae species which naturally occur in wetlands do not occur in wetlands infested with Purple Loosestrife. Different species of algae occur in the infested wetlands which are not found in great quantity in uninfested wetlands.

How is Cuyahoga Valley National Park controlling invasive plants?
On small, easily controllable populations, hand pulling and removal of the plant will be the chief method of removal. On larger populations, spot treatment will be undertaken with glyphosate applied by seasonal workers from backpack or hand held sprayers. Large brushy species will be cut down and the stump treated with herbicide. Several years of treatment may be needed to kill populations of several species listed.

Is the park trying to eradicate the invasive plants?
No. We do not have the resources to eradicate these species from the park. Invasive plants spread from seed sources in every conceivable area around the park. Unless we were able to have some measure of control over the entire Cuyahoga Watershed, eradication is not likely. Rather, we are focused on removing them from sensitive areas such as rare plant habitats, wetlands, stream corridors, and other important natural areas.

Why not just let nature take its course?
Invasive plants are plants brought by humans beyond the range where they naturally could have occurred. This is not a natural condition; it is the result of human activity which threatens native plant communities and decreases biological diversity. For this reason, Executive Order 13112 requires federal agencies to control populations of invasive species in a cost effective and environmentally sound manner.

I just saw this same plant elsewhere in the park. Why is the park controlling plants right here and not there?
The park has been prioritized in order to systematically deal with invasive plants. We are working first in areas with significant natural values, and small amounts of invasive plants. Over time, these less infested areas will be kept clear of high concentrations of invasive plants. At that time, we will begin work in areas of heavier infestation as resources are available to do so.

Won't the plants just grow back?
Yes, some of them will grow back. Persistence is the key. Over time we will make a big difference by repeatedly managing the same areas. In some species like garlic mustard, several years will deplete the invasive plant population rather well, while other species are more resistant to treatment and hence require many years and different management methods. In the case of invasive plants which are not susceptible to manual control, the park uses herbicides carefully to ensure more effective control. These chemicals are not used in areas where ecological harm could result from their use.

Won't it take more to restore the plant communities, or is removing invasive plants enough?
Areas managed to date have shown a great ability to recover after removal of invasive plants. Areas which are severely infested, such as large populations of Japanese knotweed, are less likely to be restored to natural plant communities by simply keeping invasive plants out. Planting with native herb, shrub and tree species may be required in such areas due to lack of native seed sources, intense competition or other factors. If necessary, plans will be made for more intensive restoration activities in those areas.

What more can be done?
Long term solutions to the issue of invasive species impacts are very complicated. A large part of the answer will be educating landowners, the general public and garden centers about invasive plants and what they can do to prevent their spread. For more information, go to www.invasivespecies.gov. or for additional information about each species, visit www.nps.gov/cuva/management/rmprojects/invasiveplants.htm.

Can I help?
Cuyahoga Valley National Park is developing a volunteer-based, long-term invasive plants monitoring and controlling program. This program features the adoption of sections of the park by volunteers who are trained to look for and control invasive plants. It is a great chance for volunteers to experience the lesser known areas of the park while helping to conserve biodiversity. The park also works with community organizations and other groups who want to donate “in-service” hours to help with the invasive plant issue. If you are interested in participating in this program, please contact Science & Resource Management staff at (330) 342-0764 x. 5 to be included in mailings about opportunities to help the Exotic Plant Management Program. The Exotic Plant Management work schedule is posted at www.nps.gov/cuva/friends/invasiveschedule.htm.

Last Updated: Monday, 14-Nov-2005 10:55:57 Eastern Standard Time
http://www.nps.gov/ /archive/cuva/management/rmprojects/factsheets/invasiveplants.htm
Questions? Contact us