Prairie
Natural Lands Prairie 2021 | Photo Credit: Andy Harrison
A Brief History
Once having over 18 million acres of prairie, Minnesota now has only a little over 1% of native prairie remaining.¹ This dramatic decrease in prairie can be attributed to colonization and settlement by Europeans. Prairies are also fire-dependant ecosystems, so as a result of colonizers stealing this land from Native Americans, who were largely responsible for maintaining the prairie ecosystem by using prescribed burns, the prairie could be quickly overtaken by woody species.² Most of the remaining native prairies today are in a fragmented state, existing on private land, restoration sites, abandoned plots.
Currently, St. Olaf College has restored over 150 acres of native prairie on College-owned land that has been farmed in corn for decades. While it is not a restored prairie St. Olaf stopped renting out the land to farmers and restored to native habitat in a permanent easement.³ In 1989 St. Olaf faculty and students planted the first section of prairie, where 10 species of grasses and between 25-40 species of forbs (broad-leaved flowering plants) were sown initially.³ This project expanded and over the next couple of years and expanding the areas that are being replanted.
Prairie Plants
Prairies make up a majority of the St. Olaf Natural Lands. The prairies in Minnesota are known as tallgrass prairies because the dominant grasses grow very high. Some of the most common grasses in the Natural Lands include big bluestem (Andropogon gerardi) and Indian grass (Sorghastrum nutans). Along with grasses there is great diversity in plants including members of the rose, aster, legume and many others.⁴ Most of the other non-grass plants in a prairie are less than 3 feet tall and some of the grass species can grow to be up to 8 feet tall.⁴ In some intact prairies can contain around 350 different species, but this is harder to replicate in planted prairies.³ The species that are grown in St. Olaf’s natural lands are grown from seeds purchased from Prairie Restoration, Inc because it allows for the use of seeds of local origin.
To learn more about some of the most common species that you will encounter in the Natural Lands and across Minnesota, take a look at this link!
Management
Many different forms of management are used in the prairies of the Natural Lands to accomplish the various goals of the college. One of the most common management practices is the mowing of existing cross-country trails to maintain the length vegetation. Other management forms include the collection and spreading of native plant seed, monitoring of bird populations, and removal of invasive plant species. This removal can be done in different ways depending on the target species. Some invasive species, such as bird's-foot trefoil (Lotus corniculatus) are removed by shovel so that the taproot of the plant is severed. Other species such as white or yellow sweet clover (Melilotus albus, M. officinalis) are able to be pulled up by hand. Woody species can be cut low to the ground with brush cutters. Brush cutters are also effective for cutting invasive grasses or forbs such as reed canary grass (Phalaris arundinacea) or Canada thistle (Cirsium arvense). Herbicide can be another effective way to reduce invasive plant populations and has been used to treat stumps of woody species, and large patches of Canada thistle and bird's-foot trefoil. An additional type of management that is crucial for the continuation of the prairie is prescribed burns, which you can learn more about by clicking below.
All three Youtube videos showcase a mere fraction of the beauty contained in the St. Olaf Natural Lands Prairies. Original footage was captured and uploaded to Youtube by Andy Harrison
This video shows a bumblebee crawling and flying around some beebalm, also known as wild bergamot (Monarda fistulosa)
Showing off how the wind can ripple through prairie vegetation, this video shows why tallgrass prairies are referred to as seas of grass
While it's common knowledge that monarchs (Danaus plexippus) enjoy milkweed (Asclepias spp.) as larvae, they're also big fans of prairie blazing star (Liatris pycnostachya)
Work Cited:
Minnesota DNR. (n.d.). Minnesota Prairie Conservation Plan. https://www.dnr.state.mn.us/prairieplan/index.html.
Leys, B. A., J. R. Marlon, C. Umbanhowar, and B. Vannière. 2018. Global fire history of grassland biomes. Ecology and evolution 8:8831–8852.
Flom, H. 2013, May 18. A Brief Environmental History of the St. Olaf Prairie. Carlton College.
Developing Environmental Indicators for Minnesota: Prairies . 1998. MN DNR.