Prairies and Savannas

As glaciers ebbed and flowed into the Ohio region, they altered the landscape forever. Perhaps the most startling effect was the creation of the Great Lakes. As the mile-high glaciers began their retreat, melted glacial water accumulated along the southern ridges of these towering ice cliffs. Sand from present-day Michigan drifted along with the water and deposited as well. Each time the glaciers retreated, another lake appeared. At least four different pre-Lake Erie lakes (Lakes Warren, Wayne, Maumee and Lundy) occurred, each with a lower lake level than the one before it. The sandy beaches from these ancient lakes still appear in Ohio's landscape, and they create some of the most remarkable natural environments on the planet. The beaches of Lake Warren formed the sand dunes seen at Erie Sand Barrens, Oak Openings, and North Kingsville Sand Barrens.

Globally significant, the Oak Openings region has more than 1,000 different plants and a large number of endangered species. The oak savanna habitat within the Oak Openings region, particularly at Kitty Todd Nature Preserve, is perhaps the rarest, with oak trees dominating the landscape carved with the yellow quartz sand of these ancient forerunners to Lake Erie.

We all know what an abandoned farmfield looks like when it's left to grow wild. At first, it sprouts tall grasses, weeds and wildflowers. It looks like a prairie, but only to the untrained eye. Left alone, the field will sprout bushes and trees. These will eventually shade the ground beneath and chase sun-loving plants away. A true prairie, such as those we still find pieces of near Lake Erie, is self perpetuating. Its plants adapt to a dry, warm way of life. The soil conditions and topography often discourage other plants from inhabiting the same area, so the prairie thrives. Visit the prairies at Resthaven Wildlife Area and the lakeshore grasslands at Maumee Bay State Park, or watch the May dance of the Lakeside Daisy at Lakeside Daisy State Nature Preserve. Both are portions of prairies which once covered approximately 2 percent of the State of Ohio 4,000 years ago. At least three large prairie remnants exist within the Lake Erie Coastal Ohio area -- the Marblehead Prairie, the Firelands Prairie and the Castalia Prairie.

Prairie life is harsh, but the plants adapt quite cleverly. Common characteristics of prairies are the tall grasses and the constant stream of blooming wildflowers. Prairie grasses stretch up to twice their height into the ground with root systems designed to adapt to arid climates. At Irwin Prairie State Nature Preserve, the sand layer is very thin and surface water collects on the impervious clay soil beneath. This prevents tall trees from moving into the meadow, which would ultimately block the sun from baking the soil, allowing other non-native species to emerge.

The wildflowers of the prairies (known as forbs) extend roots even deeper into the soil, passing layers of grass roots and sometimes reaching more than 10 feet long. This prevents wildflowers and grasses from competing with one another for water. The wildflowers often exhibit hairy stems to reflect the sun's rays and have leaves which are vertical, rather than horizontal like most flowers. The vertical leaves prevent the sun from beating down directly on the plant.

Some adaptations are quite clever. For example, most prairie plants have crowns beneath the soil surface. For this reason, fire is often used to reduce woody plants, lengthening the growing seasons by allowing the bare soil to heat earlier in the spring and to release nutrients.
When elk and bison roamed these prairies, wildfires were common as lightning ignited dry grasses. Because the plants have crowns beneath the soil, their futures were protected, while non-native species were destroyed. Fire is still used as a natural way to protect the integrity of these rare habitats.

Since many of the prairies and grassland savannas often occurred amid swamp forests, the clearings produced by these so-called islands attracted Native American settlement. Early traders and explorers used the sand ridges as traveling routes, and if you drive Euclid Avenue in Cleveland today, you'll be traveling atop an ancient Lake Warren beach. Man began clearing timber, plowing prairies and draining wetlands as early as 1830, and timbering was in full swing by 1910. The prairies of Ohio left behind a legacy. By the time man arrived in Ohio, many of the prairies had already retreated. However, the organic material formed from the dead prairie plants created layers of rich, dark soil.