CULTURAL PRACTICES AND ECOLOGICAL CONSIDERATIONS IN ESTABLISHING NATIVE SHRUBS ON MINED LANDS: A CASE STUDY ON ARTEMISIA TRIDENTATA SSP. WYOMINGENSIS

摘要

Xerophytic shrubs are an important and significant component of rangelands throughout much of the arid/semiarid world. These species provide many benefits to the function and utility of rangeland ecosystems. Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) is widely distributed over the Western United States. However, its re-establishment has proven difficult on mined lands perhaps due to poor seed quality, poor seedling vigor, and other ecological and edaphic factors. Research has shown that topsoil management and mulching positively influences sagebrush seedling establishment. However, perennial grass establishment has reduced sagebrush establishment through competition for soil moisture. Research presently underway evaluates the effects of sagebrush seeding rate and grass seeding rate on the establishment of Wyoming big sagebrush in an attempt to determine a suitable combination that will allow for the required seedling density of the shrub and still result in adequate erosion protection and production for the reclaimed landscape. Sagebrush seedling density has shown significant increases with increased sagebrush seeding rate; however, sagebrush seedling density has not shown a significant response to grass competition. Precipitation was considerably above normal during the spring after seeding; therefore, grass seeding rate did not result in soil moisture competition. Late summer observations have shown a reduction in sagebrush seedling density with increased grass competition. Researchers have postulated that easy to establish "pioneer" shrub species will enhance ecological and edaphic conditions and improve the subsequent establishment of more desirable and difficult to establish species. However, using Atriplex canescens as a "pioneer" species neither enhanced sagebrush establishment nor exhibited any "exclusionary" effects on Wyoming big sagebrush establishment. Recent technological advances in the establishment of Wyoming big sagebrush will greatly enhance the success of this species on mined lands in the arid/semiarid United States.