Spirit Mound Restoration
Spirit Mound, near Vermillion, SD, is a historically significant site because it was culturally significant to the Native American tribes who lived in the region and it is one of the few locations that was clearly described by Lewis and Clark on their voyage across the country in 1804. Spirit Mound was historically tallgrass prairie, but like most of this region, it was converted into agricultural production in the mid-19th century. Recognizing the historical significance of Spirit Mound, the State of South Dakota purchased the site in 2001 and began restoring prairie throughout the 320-acre site. In 2003-2004, an initial site assessment, including a vegetation survey and mapping of soil characteristics, was completed (Vote 2004), and this research re-assessed the vegetation in 2013 to compare changes to the plant community composition between 2004 and 2013.
Here is an article that Meghann Jarchow wrote for the Spirit Mound Trust newsletter in December 2014 summarizing the research:
Tallgrass prairie restoration has been ongoing for more than a decade at Spirit Mound with the initial seeding of the site occurring in the fall of 2001 and spring of 2002. Management efforts at Spirit Mound have included both prairie restoration and reconstruction. Restoring a prairie refers to facilitating the re-establishment of prairie plants within an existing prairie that has been taken over by another plant community, which in the case of Spirit Mound is primarily smooth brome (Bromus inermis) – a non-native species. Reconstructing a prairie refers to establishing a prairie on land where the former prairie has been removed, generally from agricultural use. Most (70%) of Spirit Mound is reconstructed prairie on land that was formerly used for row-crop agriculture, and 23% of Spirit Mound is restored prairie that was formerly used for intensive livestock grazing. The restored prairie is primarily on the mound and along the creek.
Most of the former cropland was seeded with a 28 species tallgrass prairie mix – although the area immediately surrounding the trail was seeded with a 36 species mix – following a soybean crop so there were no established plants. Initial restoration efforts on the mound included seeding over the existing vegetation with a 34 species mix of dry-adapted prairie plants and planting plugs along the eastern slope of the mound. The areas around the creek were not initially seeded. Additional restoration efforts including multiple seed additions have occurred around the mound and creek since 2002.
In order to assess the early establishment of the prairie plants, Rustan Vote (now Rustan Krentz), a former graduate student at USD, and her advisor Karen Olmstead, conducted vegetation surveys in 2003 and 2004 at Spirit Mound. Ten years after Vote and Olmstead’s work, Alice Millikin, a former graduate student working with me, conducted a follow-up vegetation survey. Both Vote and Millikin found that the plant community composition different among different areas at Spirit Mound, but the greatest differences were between the restored and reconstructed areas.
In the restored areas of Spirit Mound, smooth brome was dominant in 2004 (57% cover) and remained dominant in 2013 (59% cover). Whereas, in the reconstructed areas, the plant community was dominated by early-establishing prairie species especially Canada wildrye (Elymus canadensis; 50% cover) and weedy annual species including prickly lettuce (Lactuca serriola; 8% cover) and yellow foxtail (Setaria pumila; 5% cover) in 2004 and transitioned to species more common in established tallgrass prairies including Indiangrass (Sorghastrum nutans; 25% cover), bergamot (Monarda fistulosa; 15% cover), and little bluestem (Shizachryium scoparium; 14% cover) by 2013. Overall plant diversity and species richness were higher in the reconstructed areas than the restored areas, with diversity and richness increasing in the reconstructed areas between 2004 and 2013. The reconstructed areas also have a much lower proportion of non-native species (seven times lower) than the restored prairie areas.
Therefore, by 2013, most of the prairie at Spirit Mound is composed of desirable tallgrass prairie species with low abundances (< 10% cover) of non-native species. Yet, restoration challenges remain in the former grazed areas where the previous non-native vegetation, primarily smooth brome, has remained throughout the restoration efforts. This research highlights the difficulty of bringing prairie back on former agricultural land, and the long-term effects that the previous land use can have on the success of a prairie restoration. Fortunately, the South Dakota Game, Fish and Park in collaboration with the Spirit Mound Trust continue to work hard to convert all of Spirit Mound back to native prairie plants.
Peer-reviewed article from the experiment:
Millikin, A.R., M. E. Jarchow, K.L. Olmstead, R.E. Krentz, and M.D. Dixon (2016) Site preparation drives long-term plant community dynamics in restored tallgrass prairie: A case study in southeastern South Dakota. Environmental Management, DOI 10.1007/s00267-016-0736-9.