WINDOM — The U.S. Fish & Wildlife Service (USFWS) is utilizing grazing as a management tool in the Windom Wetland Management District. Livestock are being used to simulate the effect that herds of bison and elk once had on prairies in pre-settlement times.

The USFWS has contracted with local cattle producers and grazing will take place on eight of the 78 Waterfowl Production Areas (WPA) and three National Wildlife Refuge (NWR) in the 12-county district. This amounts to just over 5% of the district’s acres.

Each grazed WPA and NWR has specific wildlife management goals and objectives to improve habitat. Grazing is a flexible tool and will allow managers to adjust the mechanisms of grazing such as rates, timing, duration, seasonality and return intervals to accomplish these specific habitat goals and objectives.

The effects that a herd of ungulates can have on a prairie can be wide and varying with timing and intensity. During pre-settlement times, large herds of bison and elk would graze prairies heavily for a period of time and then move on, not returning for several months or years. Throwing wildfires into the equation and over time, the prairie evolved with these cycles of disturbance followed by periods of rest. The prairies responded by increasing flowering plants, seed production and diversity.

The USFWS can take advantage of this process and use grazing to increase plant diversity, structural diversity and reduce invasive non-native plants. Grazing increases plant diversity by targeting non-native or invasive grasses, thus reducing the density of grass. The district has been involved in the Native Prairie Adaptive Management program (NPAM) for 10 years now. Through this program, it has seen an increase in native species within NPAM units since the program’s initiation in 2010.

Resting the prairie is up to six times worse than originally believed, and grazing is not as effective, although dependent on the dominant invader, is still helpful. Burning is more effective than predicted. Studies have shown that grazing has little impact on nesting attempts and in some cases, even higher nest success is found.

For more information about grazing, habitat management and its effect on natural resources or wildlife, contact biological science technician Marty Baker at the Windom WMD at 1-800-577-2875 ext. 14. Additional information about the Windom Wetland Management District can be found at http://midwest.fws.gov/windom.