Naturalist's Corner - Driftless Prairies

This month's column looks at prairies which are just hitting their summer blooming stride.

The Driftless area is home to many remnant prairies nestled at the tops of bluffs, steeply dropping along the southwest bluff slopes and on the dry sand prairies surrounding the Mississippi River.  During the summer, these lovely prairie remnants are alive with native flowers, grasses, pollinators and other insect and wildlife. Each visit throughout the summer months is a feast of beauty and discovery. 

Looking down at the steep restored Outlook Prairie, a goat prairie at Hixon Forest
Image - Larry Sleznikow

There are two main types of prairies in the Driftless area. Goat prairies - also known as hill, dry or bluff prairies - are what you often see on blufftops or steep southwest-facing slopes. 

Sand prairies are found on sand deposits surrounding the Mississippi River, especially in the La Crosse and Prairie du Chien areas of WI, MN and IA.

Wild lupines on the Trempealeau Wildlife Refuge sand prairie 

Our Driftless prairie remnants are thousands of years old. 

Up until the last two hundred years or so, these fire-dependent ecosystems were the dominant feature of the Driftless area. Looking at historic drawings from the 1800's, one sees the tall grass prairies of the southwest-facing slopes of the bluffs with occasional scrub oaks rather than the heavily forested bluffs of today. The only forests tended to be on the north slopes. Frequent fires set by indigenous people or produced naturally kept the prairies open and free of woody plants. Once settlers came in and fires were suppressed, the forests took over these habitats.

Note the unforested  bluffs
Watercolor of ‘Wabasha’s Village on the Mississippi River
Painted ca.1845 by Seth Eastman. Photo: MN Historical Society
Source: The Driftless: the land and the humans. February 1, 2021

The loss of burning to control woody plants has resulted in ever-shrinking remnants. In order to have a healthy prairie, prescribed burning on a regular basis is necessary.

Today, less than .001% of these original prairies are left. These remnants are a wild mix of rare native grasses, flowers and abundant wildlife. They store carbon and the deep-rooted plants hold the soil.

The burning allows new growth of healthy plants.  These are just a few I've seen lately. 

The lead plant is an indicator of a healthy prairie. They can live to be up to 100 years old, with deep roots.

The narrowleaf milkweed and whorled two of many milkweed species I had a chance to learn about recently.

The small skullcap is a delicate flower about 2-3” tall that is easy to miss.

Mountain death camus is named for it's toxicity to humans and livestock.

The original prairies had topsoil that was on average 15" deep - or more. The deep-rooted native forbs and grasses anchored the soil and their breakdown built it as well. When converted to agricultural uses, the farmed area eventually eroded to a mere 1-2" of topsoil. 

My "aha" learning moment on this came during my MN Master Naturalist volunteer training. We were learning the history of the Whitewater area bluffs area. The destruction of the bluff slopes occurred when prairies were replaced with farm fields. Neither wheat nor corn roots could hold the slopes. The erosion was massive and the run-off choked the river so that occasional floods became so frequent that the community of Beaver was basically flooded out and lost its population and economic base. No one would buy existing properties. The state of MN came in and bought the land and it eventually became part of Whitewater State Park and WMA. 

Above is a graphic on the floor of the Visitor Center at Whitewater State Park. It compares the root length of native forbs and grasses with agricultural plants. The long native plant roots hold the soil on steep slopes far better than crops.

We are fortunate to have so many people concerned with prairie restoration. Thanks to groups like The Prairie Enthusiasts (TPE), Friends of the Blufflands, Mississippi Valley Conservancy and other conservation- and restoration-minded groups, individuals and agencies, these amazing remnants are being restored and maintained in many places in the Driftless. Prescribed fires, invasives control and removal (buckthorn, red cedar, honeysuckle, black locust, roundleaf bittersweet are among the invasives), seed saving and broadcasting and carefully planned forest management in surrounding forests done by these groups have created a strong series of prairies throughout the region.

A lush prairie full of grasses, forbs, pollinators - and people!
Hixon Forest's Zoerb Prairie

In my next post, Prairie Hikes of Summer, I will list some prairie hikes for you to enjoy. 

See you on the trails!

Part 2 - Prairie Hikes of Summer -hiking suggestions