Assessing diversity to Improve soil health, pollinator habitat through prairie restoration

Newswise — The diverse mixture of grasses and flowering plants that covers grassland benefits bees and other pollinators and builds healthy soil. However, once this ecosystem has been disrupted, landowners and managers need to know what level of plant diversity must be established for restoration efforts to regain these benefits. 

A group of grassland scientists led by associate professor Lora Perkins and assistant professor Maribeth Latvis of South Dakota State University’s Department of Natural Resource Management are assessing how the biodiversity of restoration mixes, specifically species richness, genetic composition and relatedness, may impact soil health and pollinator habitat. The research is made possible through a three-year, more than $650,000 U.S. Department of Agriculture Natural Resources Conservation Service grant.

To do this, Perkins and Latvis are working with Marissa Ahlering, lead scientist for The Nature Conservancy in Minnesota, North Dakota and South Dakota, and research wildlife biologist Diane Larson of the U.S. Geological Survey Northern Prairie Wildlife Research Center. Wildlife biologist Cami Dixon of the U.S. Fish and Wildlife Service in North Dakota will also collaborate on the project.

The Natural Resources Conservation Service offers a variety of voluntary conservation programs that provide incentives as well as guidelines through which producers can restore grasslands. This project supports the emphasis on improving soil health and habitat for wildlife and pollinators, in particular. What the researchers learn can help enrich grassland restoration projects in the Northern Great Plains.

“We are generating fundamental foundational knowledge that has practical applications,” said Perkins who leads SDSU’s Native Plant Initiative, which supports the use of native plants on private and public lands in the Northern Great Plains.

Exploring diversity

Restoration mixtures tend to draw from common grassland families, said Latvis, who is director of SDSU’s C.A. Taylor Herbarium. “We are trying to figure out if we can enrich existing restoration mixtures, adding beneficial species that may improve restoration outcomes and enhance ecosystem services.”

Perkins continued, “We are pulling from the full suite of plants that might grow within a thriving tract of prairie—grasses and wildflowers—and we are looking beyond what you find in a normal restoration mix, trying to be broad in those plants we include.”

In summer 2022, the researchers will plant 480 plots at the Oak Lake Field Station near Astoria, South Dakota, with various mixtures of grasses and wildflowers and then measure changes in soil health and pollinator habitat. A postdoctoral research associate, a master’s student and undergraduate students will also work on the project.

Professor Charles Fenster, director of the Oak Lake Field Station, said, “The field station is an ideal place to test restoration mixtures in the Prairie Coteau to see how increased diversity, perhaps, can lead to more vibrant, healthy prairie plots. I hope the station can be a platform for other similar, highly replicated experiments to better understand the conservation and restoration of biodiversity and the services they provide to humans.”

In designing the mixtures, the researchers will consider various dimensions of biodiversity, including not only the number of species, but also genetic diversity and how closely related the species are to each other, known as phylogenetic diversity. “We are teasing apart all these aspects to see which are most impactful,” Latvis said.

Because the focus is on generating information for restoration, reconstruction and management to establish diverse communities, the species will be planted into bare, tilled soil. To evaluate the mixtures’ effect on soil health, the SDSU researchers will use NRCS soil quality indicators, including total organic carbon, nitrogen, phosphorus and organic matter.

Standard restoration mixtures are based on what producers routinely select, Perkins said. If people begin asking for specific varieties or mixes, the companies will begin carrying them.

Disseminating information

“As the project progresses, we will communicate our findings,” Perkins said. By spring 2023, the researchers will create fact sheets and two professionally produced videos detailing the different types of plant diversity and their importance for soil health and pollinators.

“One of the fun parts will be working with The Nature Conservancy to make a video explaining the levels of diversity,” Perkins said. The Nature Conservancy has produced similar videos and found them to be effective communication tools. The fact sheets and video will be available through the NRCS and The Nature Conservancy websites.

By 2024, the researchers will put together training materials and a webinar with step-by step information on how to build a diverse species mix for a restoration project that will support soil health and pollinators.

“We are distilling this research for stakeholders in our area,” Latvis said. “Everyone benefits from understanding how biodiversity impacts ecosystem services.”