By Megan Hart, Park Biologist
It’s summer in Northeast Ohio. As you walk in the cool water of the Grand River, you take a moment to soak in the world around you. Your eyes drift up from the water’s surface and come to rest on the nearby forest and the verdant plants that grow there. Pops of color can be seen from flowers blooming amongst the dense green vegetation. Birds sing from the treetops and others forage along the water for food. You may see a mammal or two bounding away or a turtle climbing out of the river to bask on the banks. You have come to one of the special habitats that can be found in Lake Metroparks: a floodplain forest.
Floodplain forests are flat forested areas that occur along streams or rivers, which usually get inundated during flooding events. Floodplains are created over time by erosion and deposition of sediment along the river course both in day-to-day water movement and flooding events. As the river shifts course due to the erosion and deposition of sediments, it creates a large flat area surrounded by areas of higher elevation.
Floodplain forest at Blair Landing
It’s easy to look at a flooded forest after a large rain or ice dam breaking event and think about nothing but devastation. However, this flooding plays an important role in the ecology of the forest. Deposition of fresh sediment and dead plant material brings rich nutrients to the soil of the floodplain. Floods are also important natural disturbances that help reset floodplains to allow for different suites of species to utilize an area. For example, a flood may wipe out a group of trees along the river, which in turn increases the amount of sunlight reaching the forest floor. This allows for different species of plants and animals to utilize these more open areas.
Floodplain forests are biodiverse in plant life. The forests consist of trees like cottonwoods, silver maples, sycamores and black willows that thrive in the moist, rich soil. In areas that hold standing water like wetlands and old oxbow lakes, plants like buttonbush and lizard’s tail thrive and are covered with pollinators. Along the riverbanks, sedges, Canada lilies, Turk’s cap lilies and joe pye weed thrive and provide important resources for pollinators. If you venture in from the riverbank, you may encounter areas of ostrich ferns, wingstem, sweet-scented Indian plantain, and other herbaceous plants that can grow to more than six feet tall. In the spring, floodplain forests are often blanketed with spring ephemeral wildflowers like bloodroot, skunk cabbage, and Virginia bluebells that take advantage of the ample sunlight before tree leaves emerge.
Great blue heron
Floodplain forests are important habitats for a wide variety of wildlife. In the summer, Eastern warbling vireos and rare prothonotary warblers sing from the trees while herons and belted kingfishers fish in the river nearby. Northern rough-winged swallows catch insects off the surface of the water and bald eagles and osprey watch for food and keep an eye on their nests nearby. During migration, a wide variety of migratory birds like warblers, flycatchers and vireos utilize these biodiverse areas as stopover areas to refuel on seeds, fruits and insects. In the winter floodplain, brown creepers and white-throated sparrows search for hidden invertebrates and last year’s seeds and fruits for food. Reptiles like Northern water snakes and midland painted turtles can be found basking in the sun on the banks. Near wetlands and vernal pools that often dot floodplains, you may hear the calling of frogs and toads and see the movement of salamanders as they trek to these areas on the first warm, rainy nights of spring. Invertebrate life also thrives in floodplains as they utilize the diverse plant life. If you’re lucky, you may spot a frolic of otters swimming through the river or an industrious beaver carrying material back to its lodge. Winter can be a great time to check a floodplain forest for tracks of wildlife that may be shy toward humans.
Warbling vireo
Floodplain forests also provide additional ecosystem services. During flooding events, floodplains forests help by slowing water speeds, storing floodwater and reducing flood peaks. Floodplains also filter nutrients and pollutants through their soil from the flood waters and water runoff from the surrounding higher ground. Though the flat land of a floodplain may seem a convenient place to build, these areas are at high risk of flooding. When floodplain forests are removed from the landscape, it causes floods to become more destructive to both habitats and human habitation. Floodplains are also under attack by invasive plant species, which threaten to overtake these natural habitats and outcompete native vegetation. Over time, this habitat can become degraded, which can cause natural processes to become disrupted and native species to be destroyed or displaced.
You can experience floodplain forests at several parks within Lake Metroparks. Parks with the best examples include:
Go out and explore the wonder of a Grand River floodplain forest.
Prothonotary warbler