What's Working for Conservation
Remnant Prairie Management
Brush Control: Regarding restoration and management of prairie remnants- On remnant prairies which are degraded by invasive brush or trees, we've seen really good results from what the MnDNR staff calls "feathering". Brush is cut along the edge of the clearing, but stop at the point where there is no groundcover. The slash of small stems can be left in place as mulch, but larger limbs should be removed. After a growing season or two to allow sunlight to stimulate the suppressed seed bank, a prescribed burn is run through this released area. This provides for soil stabilization on steeper slopes, minimizing erosion and the temporary threat to water quality in native buffer areas. Success depends on the quality of the seedbank, so it's not a good choice for previously cropped areas. We've also seen it effective where conservation trees were planted for erosion control 50 years ago. If the invading shrub is a non-native, we've added herbicide treatments for further control, but if it is an aggressive native, like plum or gray dogwood, we've relied on the cut and burn as suppression, not eradication (Jyneen Thatcher, Washington Conservation District).
Inter-seeding: Renville SWCD is using Buffer Cost-share funds to manage remnant prairies in the county. We are having great success burning non-native dominated grass stands inter-mixed with native forbs as late into May as possible. This results in invigorating the native warm season grasses while promoting the establishment of the forb seed present on the site. We are also mechanically removing invasive trees then applying chemical for spot treating stumps. DNR and Renville SWCD will be testing applications of Fusillade and Select herbicide to suppress non-native grasses for a year in order to allow establishment of native grasses; along with using select herbicide to suppress grasses while inter-seeding forbs (Renville SWCD).
Herbicide Impacts: Our main remnant prairie problems are road authorities mowing them in August, in spite of signs and repeated phone calls reminding them not to mow the native prairie every year. Other issues are broadcast spraying along railroads and/or drift from agricultural spraying. Invasive species are also an issue in some areas (DNR Roadsides for Wildlife Program).
Smooth Brome Grass: We found a significant loss of remnant prairies along railroads in southern Minnesota due to encroachment of smooth brome grass. Brome was overwhelming native plant communities in Mesic soils where no maintenance (neither cutting or burning) has been performed for the past 10 years or more. This speaks to a need for long-term maintenance (Tony Randazzo, HDR).