Date of this Version
Final Report: JFSP Project Number 07-1-3-12
Annual grass invasion in the Great Basin has increased fire size, frequency and severity. Post-fire restoration to provide functional native plant communities is critical to improve resistance to weed invasion. Our ability to successfully re-establish mixtures of native grasses, forbs and shrubs, however, is limited. We examined the effects of the standard rangeland drill and a minimum-till drill, seeding strategies for small-seeded species, and Wyoming big sagebrush (Artemisia tridentata Nutt. spp. wyomingensis Beetle & Young) seeding rates on seeding success in burned shrub communities at four sites in the northern Great Basin. Seeded and recovering vegetation, as well as soil physical and chemical characteristics, were monitored for two growing seasons following treatment. In addition, provision was made for long-term evaluation of grazed and non-grazed seedings to assess community dynamics in relation to management practices. Results underscore the impact of precipitation and recovering residual species on seeded species emergence and establishment. Emergence of drill seeded species was generally enhanced when seeded through the rangeland drill compared to the minimum-till drill, but this effect was lost by the second year. Wyoming big sagebrush emergence was erratic, but tended to be greater when seeded through the minimum-till drill at moderate or high rates (approximately 250 and 500 pure live seed m-2) compared to the low rate (50 pure live seed m-2). Cheatgrass and other exotics were reduced and basal gap lengths decreased where native seedings established or residual natives recovered, but both increased where seedings failed due to low precipitation. Considerable soil erosion occurred in burned areas, as indicated by dust production, soil stability, and soil microrelief. Fire substantially increased dust flux rates due to decreased soil stability; however, neither drill affected these processes. Amounts of soil movement via dust flux rates and changes in soil microrelief varied throughout seasons but were not affected by drilling. While wildfire altered some soil micronutrients, drilling and seeding rates did not alter chemical responses to fire. Further work is needed to link plant and soil responses, which may help to explain plant establishment after fire and seeding treatments. Vegetation data from this research will be archived in the USGS Land Treatment Digital Library to inform future management and rehabilitation programs.
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