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 research was accomplished at the Belle Ayr West mine, south of Gillette, WY using a randomized complete block with three big sagebrush seeding rates (1, 2, and 4 kg PLS /ha) and seven grass seeding rates (0, 2, 4, 6, 8, 10, and 14 kg PLS /ha ) experimental design. Field data were collected from 1997-2004 and re- sampled in 2010 to evaluate the long-term effects of these seeding rate treatments on big sagebrush density and plant canopy volume. Wyoming big sagebrush average density decreased by 25-33 % from 2004 to 2010 but the density remained above the 1 plant/m 2 level required by regulatory standards. Wyoming big sagebrush average canopy volume in 2010 (per plant) 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 WY. General sage grouse requirements are 1.5 plants/m 2 , a shrub height of 18 to 26.6 cm, and shrub cover of 5.5 %. General antelope shrub height requirements are 22 to 46 cm, and cover requirements are 5 to 30 %. This emphasizes the importance of grass and sagebrush seeding rates necessary to achieve these desire goals.

Post-mining revegetation efforts often require grass seeding and mulch applications to stabilize the soils at the same time as shrub seeding, creating intraspecific competition between seeded shrubs and grasses that is not well understood. Artemisia tridentata Nutt. ssp. wyomingensis (Beetle and Young) (Wyoming big sagebrush) is the dominant premining shrub oil many Wyoming mines. The Wyoming Department of Environmental Quality, Land Quality Division requires reestablishment of I shrub m(-2) on 20% of post-mined lands in Wyoming. Reclamationists seldom document the impacts of grass competition on shrub canopy size after reclamation plantings become established even though shrub canopy development is important to vegetative structural diversity. In 1999, we initiated a study at the Belle Ayr Coal Mine near Gillette, Wyoming, to evaluate the influence of grass competition oil establishment and growth of Wyoming big sagebrush. Combinations of three sagebrush seeding rates (1, 2, and 4 kg pls ha(-1)) and seven cool-season perennial grass mixture seeding rates (0, 2, 4, 6, 8, 10, and 14 kg pls ha-1) were seeded during winter 1998-1999. Shrub density and grass cover were assessed from 1999 to 2004. We monitored sagebrush canopy size in 2001, 2002, and 2004. All sagebrush seeding rates provided shrub densities >= 1 shrub M after six growing seasons. Grass production >= 75 g m(-2) was achieved by seeding grasses at 6 to 8 kg pls ha(-1). Canopy growth of individual sagebrush plants was least in the heaviest grass seeding rate. Reduced grass seeding rates can aid in achieving Wyoming big sagebrush density standards and enhance shrub canopy growth.

Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) establishment on mined lands in Wyoming is a critical element of reclamation success. Because of its importance to wildlife, shrub density is used to assess reclamation success for wildlife habitat in Wyoming. Research was initiated at the Belle Ayr Mine near Gillette in 1999 to evaluate the effects of Wyoming big sagebrush seeding rates and grass competition on sagebrush establishment. Sagebrush seedling densities demonstrated consistent increases with increased sagebrush seeding rates. The 4 kg PLS per ha sagebrush seeding rate resulted in significantly greater density than either the 2 or 1 kg PLS per ha seeding rate in 1999 to 2001. Grass competition (grass seeding rates of 0, 2, 4, 6, 8, 10, and 14 kg PLS per ha of a mixture of C3 native species) did not significantly affect sagebrush seedling density. However, 1999 and 2000 precipitation was above or near normal, resulting in adequate moisture for seedling emergence and growth of all seeded species. Sagebrush seedling density declined at the higher grass seeding rates in 2001, but seedling density was not significantly affected by grass seeding rates (P = 0.12). Precipitation in 2001 was well below normal, and grass competition significantly affected sagebrush seedling canopy volume. Sagebrush seedling canopies were significantly smaller at grass seeding rates greater than or equal to 4 kg PLS per ha. Continued evaluation of these treatments on sagebrush seedling performance will enable development of a seeding strategy that enhances establishment of Wyoming big sagebrush on reclaimed mine lands. Introduction ____________________ Mined land reclamationists in the Western United States must meet many requirements to achieve successful reclamation. In August 1996, specific shrub density requirements were imposed on mine reclamation in Wyoming (Wyoming DEQ 1996). This standard required that the dominant postmining shrub on lands identified as wildlife habitat be reestablished at a density of 1 shrub per m on 20 percent of the disturbed landscape. Herbaceous species can create significant competition for shrub seedlings (Eissentat and Caldwell 1988; Schuman and others 1998; Williams and others 2002). However, reclamation guidelines and regulations require topsoil stabilization immediately after the topsoil is replaced using a permanent vegetation cover that is at least as productive as premine conditions. Establishment of a perennial vegetative cover that protects the topsoil resource from erosion can prevent the establishment of shrubs and other difficult-to-establish native plants. However, establishment of both herbaceous and shrub species is necessary to provide the desired plant community diversity and appropriate species for wildlife habitat. This study was conducted to further evaluate the establishment of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) when sown at three rates with a mixture of cool-season native grasses sown at seven seeding rates (competition levels). Methods _______________________ The study site was located at the RAG Coal West, Inc., Belle Ayr Mine, 29 km southeast of Gillette, WY. Climate at the site is continental, elevation is 1,460 m, mean air temperature is 6.7 ∞C and the average annual precipitation is 376 mm (Belle Ayr Coal Mine 2001). The premine vegetation of the area is a northern mixed-grass prairie primarily comprised of cooland warm-season grasses and Wyoming big sagebrush. Soils are derived from Tertiary and Upper Cretaceous shale, limestone, and sandstone. The topsoil was a sandy clay loam, with a pH of 7.6, EC of 2.0 dS per m, total nitrogen concentration of 700 mg per kg, and a soil organic carbon content of 1.0 percent. Topsoil replacement (56 cm) was completed in December 1997 to January 1998, and the area was seeded to barley (Hordeum valgare var. “Steptoe”) in April 1998 to establish a stubble mulch. In December 1998, seven grass seeding rate treatments (0, 2, 4, 6, 8, 10, and 14 kg PLS [pure live seed] per ha) were randomly drilled into 6.5 by 27 m main plots within each of four replicate blocks. The grass mixture (approximately equal seed numbers of each species) was

Revegetation of mined rangelands in the western U.S. requires that a diverse, self-generating plant community be established that includes native woody shrubs that provide important wildlife habitat. Wyoming Department of Environmental Quality, Land Quality Division, on August 6, 1996, amended their revegetation standards to include a shrub densityrequirementthat had been sought by environmental and wildlife groups for over two decades. This standard requires that 1 shrub m· be re-established on 20% of the disturbed area and that 50% of this density be comprised of the dominant species present before mining. In Wyoming and much of the western rangelands, this typically requires the reestablishment of Wyoming big sagebrush (Artemisia tridentate ssp. wyomingensis). Hence, much research has been accomplished in the last 10-15 years to develop a better understanding of its seed physiology, seedbed ecology, and to develop cultural practices that will aid in its re-establishment. Research has increased our knowledge in many of these important areas of sagebrush reestablishment ecology and have greatly enhanced our ability to establish big sagebrush by direct seeding; however, climatic factors have a great influence on the success of its re-establishment. The paper also compares the cost of direct seeding compared to transplantation ofnursery grown seedlings to meetthe shrub density standard and shows that direct seeding costs only a fraction of the cost of transplantation. Further research efforts should be concentrated on further improving direct seeding technology and enhanced production of good quality seed. Additional