|Svejcar, Tony - Oregon State University|
|Svejcar, Lauren - Oregon State University|
Submitted to: Plant Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2016
Publication Date: 1/5/2017
Citation: Svejcar, T., Boyd, C.S., Davies, K.W., Hamerlynck, E.P., Svejcar, L. 2017. Challenges and limitations to native species restoration in the Great Basin, USA. Plant Ecology. 218:81-94. doi: 10.1007/s11258-016-0648-z.
Interpretive Summary: Low to mid elevation native plant communities in sagebrush rangeland within the US Great Basin are under severe threat from invasion by exotic annual grasses and associated increases in fire frequency. In this paper we describe challenges and limitations associated with restoring native plant communities under threat from annual grass invasion. A wide array of published literature suggests that maintenance of perennial bunchgrass populations is key to preventing invasion of exotic annual grasses, but traditional agronomic-based techniques for restoration have not had sufficient success to prevent continued annual grass expansion; particularly in light of the increased presence of fire across these landscapes. Novel approaches to overcome limitations to perennial grass establishment, such as thermal mortality and drought, will be necessary to increase restoration success and contain the expansion of exotic annual grasses on sagebrush rangeland.
Technical 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 to 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.