Challenges and limitations to native species restoration in the Great Basin, USA

Abstract

The Great Basin of the western USA is an arid region characterized by high spatial and temporal variability. The region experienced high levels of ecological disturbance during the early period of Euro-American settlement, especially from about 1870–1935. The principal plant communities of the Great Basin are sagebrush steppes, dominated by various Artemisia shrubs and perennial bunchgrasses that represent the largest rangeland ecosystem in North America. In low to mid-elevation sagebrush communities, exotic annual grasses have displaced native plant species and are associated with a dramatic increase in size and frequency of wildfires. Degradation in this region is driven by processes that cause the loss of mature bunchgrasses, which, when intact, limit exotic annual grass invasion. Historically, large economic investments to restore degraded Great Basin rangeland through establishment of native bunchgrasses, principally utilizing heavily mechanized agronomic approaches, have been met with limited success. A multitude of environmental factors contribute to the lack of restoration success in this region, but seedling mortality from freezing and drought has been identified as a primary demographic limitation to successful bunchgrass establishment. Novel approaches to overcoming limitations to bunchgrass establishment will be required for restoration success. Increased national concern and a near listing of the greater sage-grouse, a steppe-obligate species, to Endangered Species status, has spurred greater regional support and collaboration across a diversity of stakeholder groups such as state and federal land and wildlife management agencies, county planners, and ranchers.