2002-07-08_GENERAL DOCUMENTS - M2002004 (3)

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Evidence also does not seem to support the fact that more easily established shrubs, such as fourwing saltbush, enhance establishment of other shrubs such as big sagebrush; however, inclusion of multiple shrub species in the seed mixture has been shown to increase total shrub seedling density and greater plant community diversity. Research has repeatedly highlighted the many benefits of direct - placed topsoil, such as AM inoculum, better soil physical characteristics, seedbank of native species, healthy microbial populations that ensure good nutrient cycling, and enhanced water infiltration and water storage capacity. Enhanced drought stress tolerance of big sagebrush seedlings when AM associations are present highlights an important factor in improving seedling survival in an arid/semiarid environment where soil moisture levels fluctuate dramatically in the surface few centimeters of the soil. Mulch has also been shown to be critical to formation of "safe sites" for big sagebrush germination and establishment through microclimate modification. Stubble mulching is a desired practice over the use of straw mulch which is more costly, more labor intensive and has a greater potential to introduce non - desired and noxious weed species into reclaimed lands. Use of a stubble mulch has also been shown to have long -term benefits for water infiltration into the reconstructed soil profile (Schuman et al. 1980). Reclamationists have recommended and in some instances planted big sagebrush in small islands with the intention that these islands serve as seed banks for further spread of the species into the revegetated areas. However, data by Gores (1995) and Lyford (1995) showed that natural recruitment of big sagebrush into revegetated mine lands from native stands of big sagebrush was generally limited to a few meters after 10 -15 years. Lyford (1995) stated that natural recruitment decreased 50 -fold when distance to the seed source exceeded 100 m. Therefore, this approach to aiding establishment of big sagebrush will probably not be effective within the bonding time frame. Research within the last decade has produced a much better understanding of seedbed ecology of big sagebrush. Research is leading toward development of a seeding strategy for big sagebrush that should also benefit establishment of other native shrub species as well. References Allen, E.B. 1984. Vesicular - arbuscular mycorrhizae and colonizing annuals: Implications for growth, competition and succession. p. 41 -51. In: S.E. Williams and M.F. Allen (eds). VA Mycorrhizae and Reclamation of Arid and Semiarid Lands. August 17 -19, 1982, Dubois, WY. Wyoming Agr. Exp. Stn. Rpt. No. SAl261, Laramie. Beetle, A.A. and K.L. Johnson. 1982. Sagebrush in Wyoming. Wyoming Agr. Exp. Stn. Bull. 779. University of Wyoming, Laramie. Booth, D.T. 1985. The role of fourwing saltbush in mined land reclamation: A viewpoint. J. Range Manage. 38:562 -565 Booth, D.T., Y. Bai, and E.E. Roos. 1997. Preparing sagebrush seed for market: Effects of debearder processing. J. Range Manage. 50:562 -565. Booth, D.T., J.K. Gores, G.E. Schuman, and R.A. Olson. 1999. Shrub densities on pre -1985 reclaimed mine lands in Wyoming. J. Restoration Ecology. 7:1 -9. Call, C.A. and C.M. McKell. 1982. Vesicular - arbuscular mycorrhizae -a natural revegetation