With its long history of ecological disturbance, Cuyahoga Valley National Park contains a number of non-native species. Learn more about the differences between native, non-native, and invasive species.

Plants

A 1986 study found 186 non-native plant species in Cuyahoga Valley National Park, nearly 20 percent of the park’s 943 total plant species. At least 16 species of non-native plants are currently considered threats to the park’s natural ecosystems and native flora. These plants have the potential to form large stands that crowd out native plants and provide only limited habitat value for wildlife. Many of them can become so permanently established that their populations are extremely difficult to eradicate. Resource management staff use a variety of control and management techniques to keep non-native, invasive plant species at levels that do not threaten natural conditions. Natural areas of the park are monitored periodically to ensure the efficacy of control measures. You can volunteer to help control these plants.

Insects

One non-native insect of great concern is the spongy moth. An exotic insect species from Europe, spongy moths defoliated over 4,000 acres of forest in Cuyahoga Valley in 1999. Defoliation directly affects trees by decreasing their health and vigor, which can result in an increased susceptibility to disease and parasites and increased tree mortality. Defoliation and the loss of mature trees can change forest and understory composition, water quality in streams and lakes, and quality and availability of food for terrestrial and aquatic wildlife. These changes can alter the abundance and distribution of wildlife. The park implemented a suppression program to help minimize and mitigate further moth defoliation effects. Learn more about the spongy moth.

Another pest is the emerald ash borer, a wood-boring beetle from Asia that kills ash trees three to five years after infestation. Adults are dark metallic green, and fly from May through September to ash trees to mate and lay eggs. Larvae emerge and tunnel beneath the bark, chewing on vascular tissue and interrupting the tree’s circulatory system. An infestation only becomes apparent once the canopy thins, branches die back, and death begins. By then, the insect has long since moved on. The emerald ash borer has killed millions of ash trees from Illinois to Maryland and up into Ontario. As of 2016 it has been found in all 88 Ohio counties. Learn more about the emerald ash borer.

These and other non-native species in Cuyahoga Valley are evaluated and monitored by resource management staff. As directed by the park’s general management plan, exotic plant and animal species are controlled or eradicated when possible.