You may have heard Illinois called The Prairie State. Historically, Illinois was 60% prairie1 (Figure 2), and you have probably heard it referred to as tall grass prairie (Figure 1). But, that’s where things can get a little messy.
There are actually several types of prairies. In Illinois, there are six main sub-classes: black soil prairie, sand prairie, gravel prairie, dolomite prairie, hill prairie and shrub prairie. These sub-classes are sort of divisions of the tall grass prairie. When you consider the amount of soil moisture, you get a whopping 23 types of prairies just in Illinois,2,3 and not all of those 23 can really be considered tall grass. Like I said, it can be a bit messy, but what a variety! We can’t go into all 23, so let’s narrow our focus a bit and look at prairies overall.
Prairies are a relatively young ecosystem in North America. As the ice age came to a close, our area underwent a complete transformation from tundra, to spruce forest, to hardwood forest, to the far spread prairies. Prairies were encouraged and are maintained by three environmental factors: climate, fire and grazing (Figure 3).
Prairies are adapted to warmer, drier climates and can withstand large fluctuations in rainfall. A steady fire regime keeps trees from immigrating into the area and converting it to forest, and helps recycle carbon in the soil. Browsers and grazers, from grasshoppers to bison, help in several ways. They promote growth by recycling nutrients. They also promote higher biodiversity by eating fast growing plants that may shade or suck water away from the slower growers, stirring up the soil for plants that prefer a little disturbance to their habitat4.
We owe a lot to prairies. They helped create the rich soil that we depend on for our agriculture. Fires and dung from grazers increased the carbon and nutrients in the soil, and the plants themselves help build it up too with their long roots. Many prairie plants are perennials, which mean that the same plant can grow year after year. They develop very deep roots (Figure 4) that allows them to reach deep water during dry times, but they hold on to the soil too and keep it from eroding away. This not only protects the soil but the water, too. Unfortunately, this rich soil is also the reason that prairies are the most endangered ecosystem in our nation. From the 1830’s to present day, we have plowed up and lost 99% of the tallgrass prairie1. It’s not just because of agriculture. Roads and developments prevents a natural fire regime, and without it, prairies cannot be maintained.
You may look at a grassland or prairie and think, “What’s the big deal? It’s just grass.” The loss of a prairie is a loss of an entire, unique ecosystem with incredible animals and plants like the Purple Coneflower, Prairie Kingsnake, Bobolink (Figure 5), Big Bluestem and Checkered Skipper.
Thankfully, the prairie is not without its warriors. Some fantastic work is being done to preserve what is left and reestablish several types of prairies. The U.S. National Park Service, U.S. Army Corps of Engineers, Department of Natural Resources, The Nature Conservancy, county conservation groups and many other non-governmental groups all work to preserve and restore prairies. Some of the ways they help maintain prairies and other grasslands is to remove invasive species, perform controlled burns to maintain a fire regime, and collect and spread seeds. Many preserves use volunteers to collect seeds from their plants that can be sent to other preserves to increase plant diversity and prevent plant inbreeding.
These places are absolutely beautiful (Figure 6) especially when all the flowers are blooming, and the grasses wave in the wind. I encourage you to take some time to visit one near you, or if you are traveling, take a little detour to stop by one on the way. To find some wonderful prairies in Illinois visit this tallgrass prairie database.
If you live in Iowa check out the Iowa State Preserves web site for a PDF of 95 preserves. You can also visit places in Missouri, like prairies and other preserves, which the Nature Conservancy protects.
These prairies are in danger of disappearing, and they deserve and need our protection and support. I hope you will take some time to experience these wonderful and magical places before it is too late.
- Corbett, E.A. A Comparison of Illinois Remnant Prairies, 1976 to 1988. Proceedings of the 19th North American Prairie Conference.