If any of you strolled by the Southview Oak Savanna along the University Parks Trail these last couple of weeks, you might have been asking yourself that question.

ZOOTeens

ZOOTeens moving leaf piles

TOPS Conservation Crew, along with awesome volunteers from the Toledo ZOOTeens, the University of Toledo’s Department of Environmental Sciences, and the local chapter of Wild Ones, have been hard at wok removing the fallen oak leaves from a couple of areas in the Savanna.

Why??

The Southview Oak Savanna is part of the Oak Openings Region. The soil is sandy, and on this site there is a remnant high dune built by the wind after glacial Lake Warren receded roughly 12,000 years ago. A lot of these ancient dunes are now gone, flattened for farming or bulldozed for developments. There are only a handful of places left where you can see the sweeping dunes, topped by oaks, tall grasses and wildflowers that once characterized this entire area. This is why it is such a privilege for us to have the Southview Oak Savanna, a remnant, as small as it is, of the globally unique ecosystem that once existed here.

Bare Soil - Leaves Removed!

Bare sandy soil after leaf removal. And the big piles of leaves ready to haul off.

So why do we want to remove downed leaves from this sandy ecosystem? The answer lies in that sand…and in fire and flood suppression. The tall grasses and wildflowers that grow on these ancient sand dunes rely on the sandy soil which has very low nutrient content. When dead leaves break down, they put a lot of nutrients into the soil. Historically, the nutrient content in the sandy Oak Openings soil stayed low because there weren’t that many trees growing in the sandy dunes. Nowadays there are WAY more trees in the Oak Openings Region because people have been stopping wild fires and lessening floods. Fires and floods stop trees from establishing. So now we have too many trees, dropping too many leaves, and creating soil with too high of a nutrient content for the native grasses and wildflowers.

So for the past 7 years, we have been removing the leaves from parts of the Southview Oak Savanna to make the sandy soil better able to support the rare plants that like sunny, sandy spots in the Oak Openings Region. And it’s working! Non-native invasive plants like garlic mustard love high nutrient content, and now they are gone from the Savanna! And rare native plants are really making a comeback!

Take a look at some of the wildflowers blooming at the Savanna this spring and summer.

Butterfly Milkweed

Butterfly Milkweed with Bee

There wouldn’t be nearly as many of them if we didn’t clear out those leaves for them every year!