Many areas of the refuge were historically plowed and agricultural crops grown on them. This effectively eliminated the native plant communities that existed. After the refuge acquired these areas, most of the acres were planted to crested wheatgrass and smooth bromegrass. Over the next 70 years, these exotic cool season grasses became well established and the native plant species which existed here never returned. Refuge staff believe that re-establishing and maintaining diverse native plant communities provides the best long term and sustainble solution to providing wildlife habitat on the refuge. Native plant communities are well adapted to wide variations in climate that occur from year to year and respond favorably to prescribed burning, grazing, and water level manipulations. Diverse native plant communities are more resistant to invasive species. Diverse native plant communities also provide the habitat requirements needed by the suite of grassland birds found here.
An aggressive prairie restoration program began on these acres in 2001. Approximately 500 acres of existing cropfields were planted back to a 5 to 7 species mix of native grasses. In 2004, refuge staff began the process of converting over 5,000 additional acres of crested wheatgrass, smooth bromegrass, and Kentucky bluegrass to a more diverse native plant community. We have found that in some situations, farming an area for 4 or 5 years is needed to elimate the extensive root system that smooth bromegrass and Canada thistle has. Other areas have erosive soils or may have remnant native prairie species remaining where the use of herbicides to remove the exotic species may be warranted. It is expected that 3 successive years of herbicide treatments, applied early in the spring or late in the fall, will be needed. Once the undesireable exotic species have been removed from the area, reseeding efforts can begin.
A combination of techniques are being utilized. Seed from native prarie species found on the refuge and surrounding lands is harvested by hand or with the aid of an ATV pulled seed stripper. We also purchase commercially available native species when few or no harvest sites exist for that species. A goal of including 80-100 species in the mix has been set. The seed is run through a hammermill which breaks the seedheads apart. Custom seed mixes are then put together for the different soil types being reseeded. Cleaned seed can be planted with the grassland drill. Seed which the refuge staff harvests is not cleaned and is typically planted with either an ATV mounted or tractor mounted vicon spreader. Followup management includes prescribed burning and/or grazing. We have also seeded lighter rates in successive years to facilitate the "seed rain" into the site.
We have found that wetter sites establish quickly while the drier upland sites take more time to become well established. Typically, annual weeds are to be expected early in a seeding. The perennial native plants put much of their initial energy into growing root systems, allowing the annual plants to dominate. As the native plants develop stronger root systems, they begin to suppress the growth of the annual plants, eventually dominating the site. While the native prairie which once existed can never truly be restored, a more diverse native plant community is the goal.