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ARS Home » Pacific West Area » Burns, Oregon » Range and Meadow Forage Management Research » Research » Research Project #436167

Research Project: Restoration and Conservation of Great Basin Ecosystems

Location: Range and Meadow Forage Management Research

2022 Annual Report

The long-term objective of this project is to develop practices and strategies to restore and conserve Great Basin rangelands. Specifically, during the next five years we will focus on the following objectives: Objective 1 (Restoration): Develop practices and strategies for restoring perennial livestock forages and ecosystem function on degraded and fire-prone Great Basin rangelands using combinations of grazing management, vegetation treatments, seed enhancements, and traditional restoration techniques. Subobjective 1A: Develop seed enhancement technologies for overcoming barriers to rangeland seeding success. (Davies, Boyd, Copeland) Subobjective 1B: Determine appropriate seed mixes for use after wildfires to limit exotic annual grass invasion and restore productivity. (Davies, Boyd, Copeland) Subobjective 1C: Develop and evaluate management practices for controlling juniper encroachment of sagebrush steppe plant communities. (Bates, Davies) Subobjective 1D: Determine post-treatment change in vegetation composition and structure over a 30 year time horizon in cut compared with burned juniper-encroached sagebrush steppe. (Boyd, Bates, Davies) Objective 2 (Conservation): Develop practices and strategies (including decision-support tools) to maintain and enhance livestock forage production and other ecosystem services in rangelands across different site characteristics, climate conditions, and management systems. Subobjective 2A: Evaluate grazing management as a tool to decrease wildfire risk, behavior, and severity. (Davies, Bates, Boyd, Copeland) Subobjective 2B: Evaluate post-fire grazing management effects on herbaceous productivity and sage-grouse habitat. (Bates, Davies) Subobjective 2C: Determine the influence of site attributes and climate variation on long-term productivity and diversity of sagebrush steppe. (Bates, Davies, Copeland) Subobjective 2D: Develop a science-based framework for management planning. (Boyd, Bates, Davies) Subobjective 2E: Use precision management technologies (global positioning of livestock, virtual fencing, remote sensing of landscape and others) to enhance livestock producer capability for optimum management of pastures and rangelands, balancing production and ecosystem services.

Objective 1: Hypotheses: 1) Incorporating seeds into activated carbon pellets will protect seeded vegetation from pre-emergent herbicides, 2) Seeds treated with abscisic acid will have delayed germination and increased seedling density relative to non-coated seeds, 3) Coating and imbibing treatments will produce similar seedling densities, 4) The effects of abscisic acid treatment will be dependent on level of coating; based on previous lab work we hypothesize that intermediate levels of treatment will produce highest seedling densities, 5) Drill seeding a mixture of native and introduced bunchgrasses after wildfire in sagebrush steppe will reduce exotic annual grass invasion compared to seeding native bunchgrasses, seeding introduced bunchgrasses, and not seeding, 6) Burning juniper-encroached sagebrush steppe will increase desirable herbaceous production, 7) Herbaceous vegetation productivity and abundance will be greater when juniper is controlled with either fall broadcast burning treatment or clear-cut/slash burning treatment compared to untreated woodlands, 8) Clear-cut/slash burning of encroaching junipers will produce more favorable habitat characteristics for sage-grouse compared to fall broadcast burning, 9) Juniper cover and density will increase at a faster rate in cut vs. burned western juniper plant communities, 10) Cover and density of mountain big sagebrush will decrease in association with burning but will recover to levels in cut treatments within 30 years, 11) Rate of increase in density and cover of large perennial bunchgrasses will be faster in burned vs. cut treatments, and 12) exotic annual grasses will initially increase more in the burned compared to the cut treatment. Objective 2:Hypotheses: 1) moderate livestock grazing compared to grazing exclusion will reduce fine fuel continuity, height, total biomass, and accumulation of residual biomass on perennial grass crowns and 2) decrease fire-induced mortality of perennial grasses and thereby reduce post-fire exotic annual grass invasion, 3) increasing grazing pressure will reduce fuels and thereby decrease fire ignition potential and propagation, 4) Long-term heavy rotational grazing after fire will decrease herbaceous productivity, sage-grouse dietary forbs, and horizontal screening cover compared to light, moderate, and no grazing treatments, and 5) No grazing and light grazing will have greater herbaceous productivity, sage-grouse dietary forbs, and horizontal screening cover than moderate grazing. Experimental approaches and research procedures: We will use a combination of grow room studies and small and large replicated field studies to answer these research questions. Many of these field studies will be long-term studies. If initial research plan is unsuccessful, we will revise our grow room and field studies to address the reasons why our initial research plan was unsuccessful or replicate the original experiment if it was unsuccessful because of an act of nature.

Progress Report
In support of Objective 1, scientists in Burns, Oregon, collected data on grow room and field experiments designed to test the effectiveness of activated seed coatings and carbon pellets at protecting seeds from pre-emergent herbicide damage. The researchers prepared a peer-reviewed manuscript on the effects of activated carbon pellets and seed coatings on species with different sized seeds. They also collected data on grow room and field plots designed to evaluate coating and imbibing seeds with abscisic acid to delay germination. A peer-reviewed manuscript was prepared on seed enhancement technologies. Researchers and support staff collected data on experiments evaluating drill-seeding native compared to non-native grasses after wildfire and experiments investigating the effects of burning juniper on herbaceous production. A peer-reviewed manuscript on the effects of seeding native compared to introduced bunchgrasses after wildfire in sagebrush steppe communities was also prepared. In support of Objective 2, researchers continued to collect data on experiments designed to evaluate grazing management as a tool to decrease wildfire probability, behavior, and severity. Peer-reviewed manuscripts on the effects of pre-fire grazing on post-fire community recovery were prepared. The researchers continue to evaluate the effects of grazing after fire in sagebrush steppe communities. A peer-reviewed manuscript on the effects of grazing after fire in annual grass invaded sagebrush steppe communities was prepared. The researchers continue to develop management-oriented materials to guide rangeland management based on ecological threats and the influence of management and non-management factors on plant community change.

1. Fire, not fall-winter grazing, increases exotic annual grasses. Exotic annual grass invasion is a major threat to western North American rangelands by decreasing biodiversity and promoting frequent, large wildfires. Overgrazing and fire have historically both been implicated as contributors to the exotic annual grass problem. However, experimental comparisons between contemporary grazing, especially fall and winter (off-season) grazing, and fire are lacking. ARS researchers in Burns, Oregon, compared the effects of moderate grazing during the off-season and fire in sagebrush communities. Fire, but not grazing, substantially increased exotic annual grass abundance and cover. In fact, moderate, off-season grazing reduced exotic annual grasses in sagebrush communities. These results suggest that fire, but not off-season grazing, is a threat to the sustainability of sagebrush communities at risk of exotic annual grass invasion.

Review Publications
Pau, S., Nippert, J.B., Slapikas, R., Griffith, D., Bachle, S., Helliker, B.R., O'Connor, R.C., Riley, W.J., Still, C.J., Zaricor, M. 2021. Poor relationships between NEON Airborne Observation Platform data and field-based vegetation traits at a mesic grassland. Ecology. 103(2). Article e03590.
Smith, J.T., Allred, B.W., Boyd, C.S., Davies, K.W., Jones, M.O., Kleinhesselink, A.R., Maestas, J.D., Morford, S.L., Naugle, D.E. 2021. The elevational ascent and spread of exotic annual grass dominance in the Great Basin, USA. Diversity and Distributions. 28(1):83-96.
Bates, J.D., Davies, K.W. 2022. Early succession following prescribed fire in low sagebrush (Artemisia arbuscula var. arbuscula) steppe. Western North American Naturalist. 82(1):50-66.
Boyd, C.S., O'Connor, R.C., Ranches, J., Bohnert, D.W., Bates, J.D., Johnson, D.D., Davies, K.W., Parker, T., Doherty, K.E. 2022. Virtual fencing effectively excludes cattle from burned sagebrush steppe. Rangeland Ecology and Management. 81:55-62.
Copeland, S.M., Hamerlynck, E.P., Holfus, C., Campbell, E., Boyd, C.S. 2021. Stomatal conductance relates to sagebrush transplant survival across planting season and size-class. Rangeland Ecology and Management. 80:26-30.
Schroeder, V.M., Johnson, D.D., O'Connor, R.C., Crouch, C., Dragt, W.J., Quicke, H.E., Silva, L., Wood, D.J. 2022. Managing invasive annual grasses, annually: A case for more case studies. Rangelands. 44(3):210-217.
Johnson, D., Boyd, C.S., O'Connor, R.C., Smith, D. 2022. Ratcheting up resilience in the northern Great Basin. Rangelands. 44(3):200-209.
Davies, K.W., Boyd, C.S., Bates, J.D., Hallett, L.M., Case, M.F., Svejcar, L.N. 2022. What is driving the proliferation of exotic annual grasses in sagebrush communities? Comparing fire with off-season grazing. Rangeland Ecology and Management. 82:76-85.
Davies, K.W., Boyd, C.S., Copeland, S.M., Bates, J.D. 2022. Moderate grazing during the off-season (fall-winter) reduces exotic annual grasses in sagebrush-bunchgrass steppe. Rangeland Ecology and Management. 82:51-57.
Davies, K.W., Copeland, S.M., Bates, J.D. 2022. Grazing effects on shrub-induced resource islands and herbaceous vegetation heterogeneity in sagebrush-steppe communities. Global Ecology and Conservation. 35. Article e02106.
Davies, K.W., Bates, J.D., Boyd, C.S., Svejcar, L.N. 2022. Using postfire spatial variability to improve restoration success with seeded bitterbrush. Rangeland Ecology and Management. 83:117-123.
Hamerlynck, E.P., O'Connor, R.C. 2021. Photochemical performance of reproductive structures in Great Basin bunchgrasses in response to soil-water availability. AoB Plants. 14(1). Article plab076.
Boyd, C.S. 2022. Managing for resilient sagebrush plant communities in the modern era: We’re not in 1850 anymore. Rangelands. 44(3):167-172.
Copeland, S.M., Bradford, J.B., Hardegree, S.P., Schlaepfer, D.R., Badik, K.J. 2022. Management and environmental factors associated with simulated restoration seeding barriers in sagebrush steppe. Restoration Ecology. Article e13722.
Davies, K.W., Wollstein, K., Dragt, B., O'Connor, C. 2022. Grazing management to reduce wildfire risk in invasive annual grass prone sagebrush communities. Rangelands. 44(3):194-199.