Location: Range and Meadow Forage Management Research
2018 Annual Report
Accomplishments
1. Establishment from seeds is central to the survival of predominantly asexual bunchgrasses. Understanding how bunchgrass populations change from initial conditions over long time scales is important for predicting restoration success in sagebrush steppe. A study by ARS researchers in Burns, Oregon, capitalizing on a spatially explicit grazing preference study established in 1998 with eight co-planted bunchgrasses, showed that after 13 years, 90% of the plants occurred in locations outside of their original planting location. This was true regardless of whether a species population increased, decreased, or remained constant over the 13-year period. These findings demonstrate that establishment from seed is the critical process in long-term changes in bunchgrass population dynamics.
2. Restorationists can use Sandberg’s bluegrass and crested wheatgrass for restoring degraded rangeland infested with insect and small rodent herbivores. Scientists in Burns, Oregon, have determined how herbivory affects the establishment of grass seedlings, and that will help improve restoration success by indicting whether or not insect and small-mammal herbivores require control to ensure establishment during restoration. In a somewhat climate controlled hoop house, seedlings of bluebunch wheatgrass, Sandberg’s bluegrass and crested wheatgrass were grown out to the two-leaf stage, then defoliated by removing either 30% or 70% of their leaf area once or twice, or not at all. At the same time, half of seedlings were subjected to low water conditions to simulate frequent dry periods encountered during rangeland restoration. Defoliation did not seem to matter to overall leaf growth, and only the most severe defoliation reduced root mass in crested wheatgrass and Sandberg’s bluegrass. Bluebunch wheatgrass seedlings were negatively affected by nearly all defoliation treatments. However, this species was the most tolerant to droughty conditions during establishment.
Review Publications
Denton, E.M., Smith, B.S., Hamerlynck, E.P., Sheley, R.L. 2018. Seedling defoliation and drought stress: variation in intensity and frequency affect performance and survival. Rangeland Ecology and Management. 71(1):25-34. https://doi.org/10.1016/j.rama.2017.06.014.
Dale, V.H., Denton, E.M. 2018. Plant succession on the Mount St. Helens debris-avalanche deposit and the role of non-native species. In: Crisafulli, C., Dale, V., editors. Ecological Responses at Mount St. Helens: Revisited 35 years after the 1980 Eruption. New York, NY: Springer. p. 149-164.
Griffin-Nolan, R.J., Carroll, C.J., Denton, E.M., Johnston, M.K., Collins, S.L., Smith, M.D., Knapp, A.K. 2018. Legacy effects of a regional drought on aboveground net primary production in six central US grasslands. Plant Ecology. 219(5):505-515. https://doi.org/10.1007/s11258-018-0813-7.
Barron-Gafford, G., Sanchez-Cohen, E., Minor, R., Hyendryz, S., Lee, E., Sutter, L., Tran, N., Parra, E., Colella, T., Murphy, P., Hamerlynck, E.P., Kumar, P., Scott, R.L. 2017. Impacts of hydraulic redistribution on grass-tree competition versus facilitation in a semiarid savanna. New Phytologist. 215(4):1451-1461. https://doi.org/10.1111/nph.14693.
Hardegree, S.P., Moffet, C., Walters, C.T., Sheley, R.L., Flerchinger, G.N. 2017. Hydrothermal germination models: Improving experimental efficiency by limiting data collection to the relevant hydrothermal range. Crop Science. 57(5):2753-2760. doi:10.2135/cropsci2017.02.0133.
Davies, K.W., Boyd, C.S. 2018. Longer-term evaluation of revegetation of medusahead-invaded sagebrush steppe. Rangeland Ecology and Management. 71(3):292-297. https://doi.org/10.1016/j.rama.2018.02.001.
Davies, K.W., Johnson, D.D. 2017. Established perennial vegetation provides high resistance to reinvasion by exotic annual grasses. Rangeland Ecology and Management. 70(6):748-754. https://doi.org/10.1016/j.rama.2017.06.001.
Davies, K.W. 2018. Incorporating seeds in activated carbon pellets limits herbicide effects to seeded bunchgrasses when controlling exotic annuals. Rangeland Ecology and Management. 71(3):323-326. https://doi.org/10.1016/j.rama.2017.12.010.
Boyd, C.S., Davies, K.W., Lemos, J.A. 2017. The influence of soil color on seedbed microclimate and seedling demographics of a perennial bunchgrass. Rangeland Ecology and Management. 70(5):621-624. https://doi.org/10.1016/j.rama.2017.03.004.
