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Ecology of Cuyahoga Valley National Park

Cuyahoga Valley National Park, nestled between Cleveland and Akron, Ohio, covers over 33,000 acres and includes forests, rivers, wetlands, grasslands, and other ecosystems that are home to the park’s diverse plant and animal species. The ecosystems in this park play a hand in creating an intricate habitat mosaic. 

Main Ecosystems


Twenty-two miles of the Cuyahoga River’s 85-mile stretch extend down the center of the park, with many large tributaries, such as Tinkers Creek, Furnace Run, and Brandywine Creek. Though the river is ecologically flourishing today, it was not always that way. The Cuyahoga River was once exposed to prolonged city sewage and factory waste, and in June of 1969, logs soaked in oil and trash that was dumped in the river caught fire. After this fire, the river was referred to as the ‘river that burned.’

While parts of the river still experience increased levels of pollution, the Cuyahoga River has made an ecological comeback. Aquatic insects, bald eagles, great blue herons, and other species are highly sensitive to fluctuations in water quality, and their appearance in and around the Cuyahoga River is an indicator of improving water conditions. Bald eagles were absent from Cuyahoga Valley National Park (CVNP) for 70 years but are now nesting again in the park. The river is home to over 40 species of fish and even more aquatic insects. Steelhead trout and northern pike live in the river; these two fish species can only survive in low-pollution water sources.

This photo shows a female bald eagle on a tree branch with a blue sky surrounding her.
Female bald eagle
This photo shows a full view of a great blue heron standing in a marsh with a fish in its mouth.
Great blue heron
This photo shows a close-up view of the head of a great blue heron.
Close up of a great blue heron

Lakes and Ponds

Cuyahoga Valley National Park has more than 100 lakes and ponds varying in size from one-tenth of an acre to over 10 acres. While several ponds are in a natural state with many wetland characteristics, all the ponds in CVNP are human made. They were originally made to act as small ponds for farms. Some of these human-made wetlands were abandoned, and over time reverted to a natural state, but not all of them. The other ponds are still used as water sources for recreation, such as fishing, kayaking, and canoeing, while others are used for agricultural activities. 

Fish species including bluegill, crappie, and bass are common in the ponds and lakes. Turtles in the park include the painted turtle, snapping turtle, eastern box turtle, the Blanding’s turtle, and the spotted turtle, listed by Ohio as a state threatened species.

This photo shows a close-up, front view of the face of a painted turtle.
Painted turtle
This photo shows the head and half of the body of a snapping turtle emerging from the surface of a body of water.
Snapping turtle
This photo shows an American coot bird standing on a log in a body of water.
American coot

Grasslands and Prairies

The grasslands and prairies of CVNP support a variety of plant species, including milkweed, aster, and goldenrod flowers. The array of plant species in the grasslands provide a space for savannah sparrows and meadowlarks to live. One of the largest restored grasslands in the park was once home to the basketball arena of the Cleveland Cavaliers until, after being abandoned since 1994, the arena was torn down in 1999. This particular grassland, given an Important Bird Area status, is home to many rare grassland bird species, including the Henslow’s sparrow and bobolink, which make their nests in the dense grasses of the area. 

Other grasslands in the park support the growth of bromegrass and switchgrass, providing an ecosystem for small insects, butterflies, rodents, and birds and attracting predators such as owls, snakes, and coyotes.

This photo shows an American copper butterfly resting among blades of grass.
American copper butterfly
This photo shows a side-view of an adult coyoto standing in a field, looking off to the right side of the photo.
Adult coyote in a field
This photo shows the side-view of a bobolink resting on a wire fence in a prairie.
Bobolink in a prairie


Forests in CVNP have had a long history of clearing and regeneration. Over a century ago, farmers cleared much of the forest to plant crops. Once those crop fields were abandoned, a secondary forest began to grow. Many of the tree species found in the secondary forest, including elm trees and chestnut trees, died from Dutch elm disease and chestnut blight, respectively, in the early twentieth century. Since then, the forest has grown again, and is now home to several species of evergreen and deciduous trees. The forest mosaic consists of tall oak and hickory trees that hide a forest understory of American hornbeam and sassafras trees. 

The coverage of the forest and the variety of trees and shrubs provide a home for the many deer inhabiting CVNP. Because deer predators such as mountain lions and wolves have long been absent from CVNP, the deer population in the park is flourishing. Deer eat bushes, wildflowers, and sprouting trees in the forest, which makes it difficult for younger saplings to survive and grow. Because there are so many deer in the forest ecosystem, they impact the types of tree, shrub, and wildflower species that grow in the ecosystem.

Insects are another factor that can change forest ecosystems. Gypsy moths are a non-native insect species from Europe that defoliated over 4,000 acres of forest ecosystem in 1999. Defoliation can leave the trees susceptible to more parasites and diseases, and can also change forest composition, availability of food for aquatic and terrestrial life, and water quality in nearby streams and lakes. Another insect affecting trees in CVNP is the emerald ash borer, the larvae of which chew through the vascular tissue in the tree. This can disrupt the circulatory system of the tree, eventually killing the tree three to five years after infestation.


This photo shows a wide-view of a group of white-tailed deer in a snowy forest.
White tailed deer 
This photo shows a close-up view of an emerald ash borer.
Emerald ash borer
This photo shows a close up of two European gypsy moths.
European gypsy moths


CVNP is home to around 1,500 wetlands that cover about 1,700 acres. Wetlands have a variety of ecosystem impacts, acting as water filters for their environment, controlling floods, and providing habitats for aquatic animals. Wetlands are also important locations of biodiversity and are home to almost half of all endangered species globally. Only about 10% of Ohio’s original wetlands remain, making the wetlands in CVNP extremely important to Ohio. 

There are two broad categories of wetlands that can be found in CVNP: full-time and part-time wetlands. In CVNP, most wetlands are part-time, meaning they are only wet part of the year. These wetlands are filled by melting snow and winter rain. Full-time wetlands, such as Beaver Marsh, stay wet year-round. This wetland is named for the beavers that formed the marsh after 1984. Part-time wetlands make amazing habitats for frogs, toads, and salamanders to lay their eggs, and full-time wetlands make great homes for willow trees, dragonflies, water lilies, and muskrats. One unique species that finds its home in marshes and wetlands is the pickerel frog. The pickerel frog is the only native poisonous frog species in the United States.


This photo shows a close-up, side-view of a pickerel frog sitting on a brown leaf.
Pickerel frog. Missouri Department of Conservation.
This photo shows a side-view of a beaver swimming in a marsh, half submerged and surrounded by lily pads.
Beaver swimming in a marsh
This photo shows a close-up of an Acadian hairstreak butterfly resting on a white and yellow flower, surrounded by grass.
Acadian hairstreak butterfly
This photo shows a close-up of a red-winged blackbird with partially outstretched wings.
Red-winged blackbird