Effects of Wyoming Big Sagebrush Seeding Rate and Grass Competition On Long-Term Density and Canopy Volume of Big Sagebrush and Wildlife Habitat.

This research was initiated in 1997 to evaluate the effects of seeding rates of grass and Wyoming big sagebrush on the establishment of big sagebrush. The study was accomplished at the Belle Ayr West coal mine, south of Gillette, Wyoming using a randomized complete block (4 blocks) experimental design with 3 big sagebrush seeding rates (1, 2, and 4 kg ha-1) and 7 grass seeding rates (0, 2, 4, 6, 8, 10, and 14 kg ha-1). Field data were collected from 1997-2004 and resampled in 2010 to evaluate the long-term effects of these treatments on big sagebrush density and plant canopy volume as it relates to wildlife habitat. Wyoming big sagebrush density decreased by 25-33% from 2004 to 2010 but remained above the 1 plant m-2 level required by regulatory standards. Average canopy volume in 2010 was 15 times greater than observed in 2004. Shrub density, cover and height met or exceeded the levels recommended for sage grouse and antelope habitat, two primary users of these lands that are a concern to wildlife management agencies and mine regulatory agencies in Wyoming. General sage grouse requirements are 1.5 plants m-2, a shrub height of 18 to 26.6 cm and a shrub cover of 5.5%. General antelope shrub height requirements are 22 t0 46 cm and cover requirements are 5 t0 30%. This research emphasizes the importance of grass and sagebrush seeding rates necessary to achieve these desired goals.