1a. Objectives (from AD-416):
The first and primary research goal of this project is to improve our systems approach to restoration for annual grass management in the sagebrush steppe of North America. In 2013, we provided a systems approach that advances ecological restoration beyond conceptual and phenomenological descriptions to quantitative process-based models that can be used to address specific applied questions (James et al. 2013a). Our systems approach uses life histories to identify transitions important to seedling establishment and maturation. It links those transitions to ecological processes directing establishment and management practices that can favorably impact those processes. Our technology transfer goal is to use the research results for developing tools aimed at assisting land managers in selecting seeds based on their quality, guidelines for determining when and what species to broadcast during restoration, and guidelines on assessing and managing defoliation of newly emerged seedlings at risk to herbivory. Specifically, during the next five years we will focus on the following objectives: Objective 1: Enhance rangeland restoration processes by improving the establishment of seedlings of desirable plant species (such as increasing seed quality and seedling survival), acquiring and implementing basic knowledge to match naturally occurring physical safe-sites with seed traits, identifying and quantifying the effects of herbivory on seedling survivorship, and developing threshold guidelines for mitigation. Sub-objective 1A: Improve rangeland restoration success by enhancing seed quality and emergence survival of desired restoration species and develop simple seed quality selection criteria. Sub-objective 1B: Develop the basic knowledge to match naturally occurring physical safesites with seed traits to maximize seedling establishment during restoration. Sub-objective 1C: Identify and quantify the effects of herbivory on seedling survivorship to develop threshold guidelines for mitigation during restoration. Objective 2: Integrate research into an ecological systems approach to restoration with current cost/benefit models and link to site-specific best management practices. Sub-objective 2A: Develop decision-support tools for 1) choosing seeds based on quality characteristics, 2) matching seed size, number, and physical safe-site availability during restoration, and 3) identifying and managing risk to seedlings associated with herbivory. Sub-objective 2B: Inform and update our systems approach to include important aspects of seed quality, maximizing physical safe-site capture, and minimizing seedlings risk of herbivory and link this model with existing cost/benefit models.
1b. Approach (from AD-416):
Rangelands cover nearly one-half of the earths land surface and provide life sustaining goods and services to about one-third of the global population. Low and variable rainfall combined with often infertile soil make the world’s rangelands highly susceptible to degradation, invasion, and global climate change (Millennium Ecosystem Assessment 2005). The inability to establish healthy plant communities is cited by stakeholders as the single largest barrier to implementing restoration and turning the tide against the hundreds of thousands of hectares of sagebrush steppe lost to invasive plants each year. Despite over a century of research, rangeland science lacks a comprehensive understanding of the ecological processes influencing seedling establishment. The goal of this project is to improve restoration for annual grass management in the sagebrush steppe of North America. Using a series of field and laboratory tests, our first study attempts to improve rangeland restoration success by enhancing seed quality and emergence survival of desired restoration species and develop simple seed quality selection criteria. Our second study is aimed at developing the basic knowledge to match naturally occurring physical safe-sites with seed traits to maximize seedling establishment during restoration. Third, we plan to identify and quantify the effects of herbivory on seedling survivorship to develop threshold guidelines for successful restoration. Finally, we will integrate this research into an ecological systems approach to restoration with current cost/benefit models.
3. Progress Report:
This progress report directly relates to Project #2070-22000-005-00D “A Systems Approach to Restoring Invaded Sagebrush Steppe.” Objectives covered in this report fall under the National Program 304. For Objective 1, studies have been initiated to improve rangeland restoration success by enhancing seed quality and emergence survival of desired restoration species and developing simple seed quality selection criteria. A study of the degree to which screening for seed mass enhances seedling emergence is completed and currently being drafted into a manuscript. All other studies to enhance seedling success by using high quality seeds are in various stages of progress. A preliminary study that focused on matching naturally occurring physical safe-sites with seed traits to maximize seedling establishment was tested and completed. Based on this study, the procedures for quantifying safe sites were improved and the larger study is underway. Primary sites have been selected and plots have been established for that portion of Objective 1. The effects of herbivory on newly established seedlings were monitored on six sites in Oregon and Idaho this spring. Plots used to test the effects of timing and frequency of herbivory on seedlings have been established and are ready to be seeded this fall. Progress on Objective 2 depends on research results gained from Objective 1.
5. Significant Activities that Support Special Target Populations:
ARS scientists at Burns, Oregon have participated in outreach activities targeted for a number of different audiences in FY 2016. This outreach has included events such as workshops, field days, and youth range camps that reached over 500 individuals. These events can potentially benefit small farms, ranching families, and holders of grazing allotments on public land by 1) maintaining the quality and quantity of the forage base and 2) by increasing the profitability of pasture and hay production. Scientists delivered instruction and provided hands-on activities related to plant identification, soil erosion, invasive species management, wildlife habitat, and grazing management to students from elementary to college age, as well as, producers and land managers.
Hamerlynck, E.P., Sheley, R.L., Davies, K.W., Svejcar, A.J. 2016. Postdefoliation ecosystem carbon and water flux and canopy growth dynamics in sagebrush steppe bunchgrass. Ecosphere. 7(7):1-21. doi: 10.1002/ecs2.1376.
Sheley, R.L., Boyd, C.S., Dobrowolski, J., Hardegree, S.P., James, J., Mangold, J. 2016. Editorial: a scientifically rigorous and user-friendly Rangeland Ecology & Management. Rangeland Ecology and Management. 69(1):1-3. doi: 10.1016/j.rama.2015.10.013.
Larson, J.E., Sheley, R.L., Hardegree, S.P., Doescher, P.S., James, J.J. 2015. Do key dimensions of seed and seedling functional trait variation capture variation in recruitment probability? Oecologia. 181:39-53. doi: 10.1007/s00442-015-3430-3.
Bansal, S., Sheley, R.L. 2016. Annual grass invasion in sagebrush steppe: the relative importance of climate, soil properties and biotic interactions. Oecologia. 181:543-557. doi: 10.1007/s00442-016-3583-8.
Larson, J.E., Sheley, R.L., Hardegree, S.P., Doescher, P.S., James, J.J. 2015. Seed and seedling traits affecting critical life stage transitions and recruitment outcomes in dryland grasses. Journal of Applied Ecology. 52:199-209. doi: 10.1111/1365-2664.12350.
Smith, B.S., Sheley, R.L. 2015. Implementing strategic weed prevention programs to protect rangeland ecosystems. Invasive Plant Science and Management. 8(2):233-242. doi: 10.1614/IPSM-D-13-00075.1.
Sheley, R.L., Sheley, J.L., Smith, B.S. 2015. Economic savings from invasive plant prevention. Weed Science. 63(1):296-301. doi: 10.1614/WS-D-14-00004.1.
Schantz, M., Sheley, R.L., James, J. 2015. Role of propagule pressure and priority effects on seedlings during invasion and restoration of shrub-steppe. Biological Invasions. 17:73-85. doi: 10.1007/s10530-014-0705-2.
Hardegree, S.P., Sheley, R.L., Duke, S.E., James, J.J., Boehm, A.R., Flerchinger, G.N. 2016. Temporal variability in microclimatic conditions for grass germination and emergence in the sagebrush steppe. Rangeland Ecology and Management. 69(2):123-128.
Svejcar, A.J., Angell, R.F., James, J. 2016. Spatial and temporal variability in minimum temperature trends in the western U.S. sagebrush steppe. Journal of Arid Environments. 133:125-133. doi: 10.1016/j.jaridenv.2016.06.003.
Davies, K.W., Bates, J.D., Boyd, C.S., Svejcar, A.J. 2016. Pre-fire grazing by cattle increases postfire resistance to exotic annual grass (Bromus tectorum) invasion and dominance for decades. Ecology and Evolution. 6(10):3356-3366. doi: 10.1002/ece3.2127.
Madsen, M.D., Davies, K.W., Boyd, C.S., Kerby, J.D., Svejcar, A.J. 2016. Emerging seed enhancement technologies for overcoming barriers to restoration. Restoration Ecology. 64(S2):S77-S84. doi: 10.1111/rec.12332.