National parks, including Cuyahoga Valley NP, protect wetland areas throughout the country. Healthy wetlands provide many environmental benefits, including improving water quality by filtering out nutrient loads and pollutants before they reach rivers and streams and moderating floodwaters. Wetlands provide habitat for a diversity of plants and wildlife and often serve as important stopover areas for migrating birds. While large wetland complexes serve an important ecological role, small isolated wetlands can be considered just as crucial for maintaining regional biodiversity (e.g., as important breeding areas for salamander metapopulations). In addition to their ecological significance, wetlands exhibit a variety of educational, recreational and aesthetic values.
Despite their importance, wetland habitats in the United States have declined dramatically since European settlement. Wetland habitats in Ohio decreased in area by 90% since the 1780s, mostly due to draining and filling for agricultural use.
Because development and urban sprawl continually threaten the wetlands that remain in northeastern Ohio, CVNP wetlands are valuable both as park and regional resources. A recent park-wide wetland inventory found more than 1,200 wetland areas encompassing approximately 1,700 acres in CVNP. Most of the wetlands are small, with only 190 larger than one acre and only 35 larger than 10 acres. Additional small wetlands may yet remain undetected.
Wetland types found in the park include marshes, wet meadows, scrub/shrub wetlands, and forested wetlands. Small emergent wetlands occurring in isolated depressions fed by surface water are most common. Small wetlands are also often found at the head of small, intermittent drainage ways, adjacent to ponds, or as seeps where groundwater flows out of a hillside. Many wetlands are partially or completely forested or include a shrub component. The largest wetlands are located within the Cuyahoga River floodplain and include emergent, shrub, and forested areas.
In addition to providing habitat for many plants and animals, special characteristics exist in some wetland areas. Vernal pools, temporary wetlands found during the rainy spring season, serve as breeding areas for many amphibian species. Potential roosting trees for the endangered Indiana bat exist in some of the wetland areas. Two great blue heronries are located in wetland areas along the Cuyahoga River.
Wetland systems in CVNP have been greatly affected by many years of disturbance and land use changes within the Cuyahoga Valley. The Ohio Erie Canal, railroad and road beds, dredging of stream channels, utility corridors, filling and grading activities, topsoiling, landfills and gravel pits, and drainage for agriculture have all profoundly influenced the current configuration of this large wetland system. Not all human-caused disturbances have resulted in a decrease in wetland area. Instead, some, such as watered remains of the Ohio Erie Canal, have increased the size of wetlands.
Humans aren't the only living things that influence wetlands. By damming free-flowing waters, beavers have affected the size and distribution of wetlands throughout the park. The Beaver Marsh, created by beavers that built a dam along remnants of the Ohio Erie Canal, offers visitors the chance to explore a wetland first-hand. Walking along the Topwath Trail boardwalk over the marsh, you can sometimes see beavers venture out of their lodge to search for food or repair the dam. Other animals, including Canada geese, northern watersnakes, and muskrats, are often seen taking advantage of the food, water, and shelter offered by this and other wetlands throughout CVNP.