Sharp-tailed Grouse - Management

Management

It is apparent that the effects of habitat fragmentation across all habitat types selected by sharp-tailed grouse are impacting this species. The management of sharp-tailed grouse habitat has changed over the years from observational (making sure current habitat is maintained) to more hands on approach. The management of lekking habitat and winter habitat are not as clearly defined in the literature as nesting and brood rearing habitat assessment and management. The development of the Robel pole and cover boards has become a key tool in habitat assessment providing land managers a means to inventory and study habitat preferences based on vegetation structure and density. The Robel pole has become the more favored of the two methods in recent years for habitat assessment. The United States forest Service (USFS) uses visual obstruction readings (VOR) to set stocking densities for cattle based on the current years standing residual vegetation . This method is currently conducted on the USFS Little Missouri Grasslands, Sheyenne National Grasslands, Cedar River National Grassland, and Grand River National Grassland, all found in the Dakota Prairie National Grasslands in North and South Dakota(Forest Service, Northern Region (USDA).2001) . The Robel pole is a non-destructive method for inventorying vegetative biomass (Robel 1970; Benkobi et al. 2000). This method was used to create a habitat suitability index based on vegetation visual obstruction (VO), ranging from 0-30.5 cm with a suitability index rating of 0-1.0 (Prose 1987). Studies of nesting habitat by Prose et al. (2002) in the Nebraska Sandhills found that nesting sharp-tailed grouse selected nest sites with visual obstruction readings (VOR) of more than 4 cm. Similarly, Clawson and Rottella (1998) observed that 58% of nests (432 of 741) in Southwestern Montana were located in sites with an average VOR of 24 cm. The other nests in this study were located in sites with VOR’s of 11–18 cm. Reece et al. (2001) observed that sites with a VO of less than 5 cm near possible nesting locations indicated a decline in quality nesting habitat as average VO declined. The use of the Robel pole to assess habitat for sharp-tailed grouse has given managers a target height of vegetation structure to have at the end of the grazing season. This allows managers to set the appropriate stocking rate to best attain a desired vegetation height. As a rule of thumb, the average VOR reading for suitable grouse nesting habitat is 3.5in (8.89 cm). Lekking habitat can be managed by burning, mowing, clear cutting, and grazing across the entire range of the sharp-tailed grouse subspecies. Ammann (1957) found that leks that contained woody vegetation did not exceed 30% of the total lek area. Similarly, Moyles (1989) found a negative correlation with increased in aspen trees (Populus tremuloides) on lekking sites and the number of displaying males present. Trees may provide perches for avian predators but further work needs to be done on the effects of tree encroachment (Manzer and Hannon 2005).