Establishing<i>Artemisia tridentata</i>ssp.<i>wyomingensis</i>on Mined Lands: Science and Economics

Abstract

In 1977, the USA Surface Mine Control and Reclamation Act mandated that reclaimed plant communities must be as productive or more productive than the premined plant community and must possess diversity representative of the premine community and serve the same land uses. In much of the Northern Great Plains this meant that reclaimed mined lands must support postmined land uses for livestock grazing and wildlife habitat. In 1996, the Wyoming Department of Environmental Quality enacted regulations governing the reestablishment of woody shrubs on mined lands. The regulation required that an average density of one shrub m−2 be reestablished on at least 20% of the disturbed land area and that the shrub composition must include dominant premine species. In Wyoming, and much of the Northern Great Plains, that meant that Artemisia tridentata Nutt. ssp. wyomingensis (Beetle and Young) (Wyoming big sagebrush) had to be reestablished on mined lands. Artemisia tridentata Nutt. ssp. wyomingensis had proven difficult to reestablish on mined lands because of poor quality seed, seed dormancy and a poor understanding of the seedbed ecology of this species. Research in the last two decades has produced significant knowledge in the area of direct-seed establishment of Artemisia tridentata Nutt. ssp. wyomingensis on mined lands. Our research has shown that reducing grass seeding rates will reduce competition and result in larger sagebrush plants that are more likely to survive and provide greater structural diversity to the plant community. Economic analyses demonstrated that big sagebrush can be established at a cost of $0.01–0.05 per seedling using direct seeding methods compared to transplanting nursery grown seedlings, estimated to cost $0.72–$1.65 per seedling (depending on size) to grow and from $1.30–$2.40 to plant (flat land to 2:1 slopes). An adequate level of precipitation will be necessary to ensure successful establishment of this species no matter what method of propagation is selected and direct seeding gives greater opportunity for success because of the demonstrated longevity of the seed to germinate 3–5 years after the initial seeding.