The benefit of Iowa’s tallgrass prairies

by Lisa Ralls
Winnebago Co. Naturalist
During the late summer months, Iowa’s roadsides and prairies burst forth with fantastic colors! These colors come from the over 500 species of plants that, historically, have made up the interwoven fabric of our prairie ecosystem. That ecosystem has been an integral part of Iowa for over 10,000 years and, although it is much reduced from what it was when the first settlers arrived, it is still vitally important.
Iowa’s first prairies appeared at the end of the last ice age, after the last of the massive glaciers retreated. When the first explorers and settlers arrived in what would eventually become Iowa, they encountered a unique ecosystem perfectly adapted to the area and the climate. The grasses grew up to 12 feet high, with underground roots extending underground just as far. And those grasses covered over 30 million acres, or 85 percent, of our future state. Obviously, Iowa’s heritage is truly that of a prairie state.
Unfortunately, within a couple hundred years, that expansive ecosystem that stretched from Canada to Mexico had practically disappeared from Iowa, falling victim to ever-improving agricultural technology. As Iowa’s prairies began to disappear, few people sounded an alarm, because few people fully comprehended the importance of those areas. But, as our prairies vanished, so did the vital benefits that they provide.
In recent years, though, there have been efforts throughout the country to restore at least some of our prairie ecosystem. By doing so, we can also bring back some of the benefits that the prairies provide, benefits that we now realize are essential to a healthy environment. And many of those benefits derive from the adaptable nature of those unique plants.
For instance, native prairie grasses have deep and extensive root systems that evolved over many thousands of years to adapt to dry conditions and fire. These roots help the grasses to utilize water deep underground or take quick advantage of sudden storms. But, they also help the plant to survive fire, since 60 percent of a prairie grass’ biomass is underground in its root system. In addition, these roots also help native plants to hold our soil in place and, in fact, the loss of our prairies was a major factor in causing the dust bowl during the 1930’s.
These root systems also allow prairies to absorb and hold excess rain and snowfall, slowing runoff and decreasing erosion. In fact, scientists estimate that prairies can handle over seven inches of rain an hour, helping to reduce the eight billion barrels of topsoil that enter Iowa rivers each year. There is no doubt that the loss of our prairies has helped to increase the frequency and severity of flooding in recent years. And, the filtering nature of the tall grasses and their fibrous roots means that water flowing through a prairie is also cleaner.
Finally, the 250-plus plant species that comprise the prairie ecosystem provide vital habitat for countless pollinator species, as well as over 50 species of mammals, over 350 species of birds, and hundreds of species of reptiles and amphibians. The tall, strong grasses provide excellent cover during the nesting season, and even more importantly during the harsh, snowy winter months. Unfortunately, many of these grassland species are among our most endangered due to the loss of over 95 percent of our prairies.
But, efforts are underway throughout Iowa and the Midwest to restore prairie vegetation wherever we can. Over the past 30 years, numerous roadways have been converted to native grasses and wildflowers, providing not only beauty for travelers, but also valuable wildlife habitat. These roadsides also provide essential wildlife corridors between fragmented areas. But, we all can help out by planting native plants wherever possible, even if it’s just in a small area. Every little bit of prairie helps.
So, this summer, as you wonder at the marvelous sight of our blooming prairie ecosystem, take a few minutes to appreciate the many benefits our prairies bestow upon us. They provide vital wildlife and pollinator habitat, hold our soil in place, help prevent flooding, and keep our water clean. That’s a lot to ask of a 10,000-year-old ecosystem. But it does it all, and in a very beautiful way.