Location: Range and Meadow Forage Management Research
2024 Annual Report
Objectives
The primary research goal of this project is to improve upon our previous systems approach to restore annual-grass-affected rangeland systems in the sagebrush steppe of North America. In 2013, we developed a systems approach that advanced ecological restoration practices from conceptual and phenomenological descriptions to quantitative process-based models that can be used to address specific applied questions. Our systems approach uses life history information to identify transitions from plant establishment through maturation and reproduction and links those transitions to the management of the ecological processes driving establishment and population growth. In our prior NP 304 project (July, 2015 to August, 2020), we are incorporating the effects of seed quality, safe-site availability, and seedling defoliation effects into our systems model for forecasting vegetation dynamics of sagebrush steppe ecosystems and are incorporating these factors into decision-support tools to guide managers in their planning and management. It is nearly impossible to reestablish native species from seeds in annual-grass invaded sagebrush steppe because seedlings struggle to break through the soil crust and survive the pulses of harsh weather conditions during establishment. In this project, we will test the potential to use growth buds harvested from crowns of native species to augment seed-based restoration efforts. Our pilot data suggests that plants growing from crown pieces that contain buds and growth primordia emerge faster than seedlings. The more substantial carbohydrate reserves of buds/primordia as compared to seeds may confer increased ability to survive harsh climatic conditions, such as those imposed by wet/dry weather pulses. Our objectives in the current project are to add critical information to our life history forecasting models and potentially provide a novel approach to restoring invaded sagebrush steppe ecosystems. Specifically, during the next five years, we will focus on the following:
Objective 1: Develop methods for harvesting, excavating, and storing buds and/or growth primordia and determine if buds and/or primordia (growth tissue around buds) of key caespitose grasses regenerate when placed in soil under near optimal conditions.
Objective 2: Quantify the environmental conditions under which buds/primordia outperform the emergence and growth of plants grown from seeds and assess the fitness (reproduction) of buds/primordia with and without seeds in comparison to seeds alone at several sites throughout the Great Basin.
Objective 3: Determine the physiological responses of buds/primordia and seeds to characterize the actual mechanism for enhanced or weakened emergence and/or survival during restoration.
Sub-objective 3A: Quantify and contrast the life histories of planted buds versus seeds.
Sub-objective 3B: Evaluate the physiological characteristics of plants established from buds versus seeds during restoration.
Approach
Because of the huge economic cost of seeding, the low probability of sown seeds establishing, and the vast amount of threatened sagebrush steppe rangeland, research scientists and managers have had to prioritize a subset of this ecosystem for restoration activities. Most restoration efforts of perennial rangeland plant communities focus on seeding-based methods; however, in established plant communities recruitment is often attributed to vegetative propagation from belowground meristems. In this project, we will test the potential to use growth buds harvested from crowns of native species to augment seed-based restoration efforts. To test the hypotheses that buds can be harvested and stored for a short period prior to sowing, whole crowns of bluebunch wheatgrass and Sandbergs bluegrass will be excavated and stored for zero, 3 weeks, and until spring as whole crowns in containers and placing containers in cold storage at a constant 2oC. After storage, buds will be placed in favorable conditions and grown for up to seven months to determine their viability. To test the hypotheses that seeds will produce more seedlings in moist environments, whereas buds will produce more seedlings in dry conditions, we will compare seedling establishment of bluebunch wheatgrass and Sandbergs bluegrass from seeds versus crown buds along a wide environmental gradient from hot/dry to cool/wet environments within a Sagebrush Steppe ecosystem. Lastly, we intend to quantify and contrast the life histories of planted buds versus seeds to determine the growth state and ecological processes associated with seedling success and failure and incorporate life history information into the existing systems approach to restoration model. Life histories of bluebunch wheatgrass and Sandberg bluegrass will be monitored in each plot described in the experiment for Objective 2. Individuals will be classified as one of the following life stages: emerged plants (1 or 2 leaves), juveniles (3+ leaves), individuals with multiple tillers, individuals with boot, individuals with inflorescence, and seed producing adults, and total seed output determined. Starting in the third year when plants have had time to mature, seed rain m-2 on the soil surface will be characterized. The soil seed bank m2 will be determined by sifting (2-mm sieve) a single randomly located soil sample before seed drop each year from each plot and that area excluded from future sampling. Survival probabilities will be estimated using Bayesian continuation ratio models to estimate the probabilities of transition between growth stages. Plant ecophysiological measurements will be made every two weeks at each location, concurrent with the life-history sampling described above. This will allow us to directly relate the effects of antecedent wintertime and growing-season soil moisture/temperature dynamics and plant ecophysiological performance to conditional probabilities of transitioning between different life stages by using them as priors for Bayesian continuation ratio models.
Progress Report
This report documents progress for project 2070-22000-007-000D, titled, “Integrate Vegetative Bud-based Propagation and Seeds in Restoration of Rangeland Native Plant Communities”, which started in March 2021.
To extend and support Objective 1, ARS researchers in Burns, Oregon, analyzed final data on an additional study aimed at determining best time of year for planting buds and if hydrogel, fertilizer, or root growth hormones, enhance establishment of bluebunch wheatgrass or Sandberg’s bluegrass from buds.
In support of Objective 2, vegetative material (biomass) from plots for comparing plant establishment from buds versus seeds has been collected and is being weighed, and newly harvested buds were sown in the fall and biomass is being collected now for comparison.
Finally, in support of Objective 3, to compare life histories and physiological differences in bluebunch wheatgrass and Sandberg’s bluegrass growing as buds versus seeds, ARS researchers have sown the fall and spring sowing of these two species. Their demographic growth is being monitored.
Accomplishments
1. Short-term precipitation and temperature forecasts predict plant establishment during restoration. Short-term climate and weather forecasting is becoming increasingly useful for informing rangeland managers about production pertaining to livestock purchasing decisions, grazing plans, wildfire fuel loads, and wildlife management decisions. Weather forecasting could also be useful for planning restoration of rangeland. ARS researchers in Burns, Oregon, and Boise, Idaho, have created a system for using available precipitation and temperature information that allows land managers to predict first year grass establishment based on short-term weather forecasting. These climate forecasts and models produce significant plant establishment forecasts with lead times of up to seven months. The ability to predict plant establishment using short-term weather forecasts is linked with plant production forecasts that are in the early stages of adoption by federal and state land management agencies and ultimately will be useful to private livestock producers and conservationists interested in restoring degraded and invaded rangelands.
2. Broadcast seeding in March improves safe site capture. Seedings are central to restoring degraded and invaded rangeland. Broadcast seedings of native species fail 95% of the time. It is critical that native seeds be broadcasted when there are physical safe sites of the proper size and shape for desired grass seeds. ARS researchers in Burns, Oregon, and Boise, Idaho, have quantified the size and number of cracks and crevices that provide safe locations for seeds. For most species, March is the period in which naturally occurring safe sites are most available. Broadcasting in March appears to be the best time for safe site capture.
3. Protecting bunchgrass leaves that grow just before the seed stalk is produced increases seed filling. Successful rangeland restoration requires producing adequate viable native grass seed. ARS researchers in Burns, Oregon, discovered that treatment of the leaf developed just prior to seed stalk emergence plays a critical role in determining the number of seeds that actually become fully “filled” with carbohydrates, which is required for a seed to be viable. For native grasses, removing the last leaf either before or after the seed stalk is produced increases the proportion of seeds in the stalk that are “filled”. This could improve our ability to commercially produce viable native grass seeds for restoration.
Review Publications
Quigley, K.M., Ziegenhagen, L.L., Hamerlynck, E.P. 2023. Seed-specific mass and root growth relate to perennial bunchgrass seedling survivorship under highly limited nutrient supply. Rangeland Ecology and Management. 90:271-278. https://doi.org/10.1016/j.rama.2023.04.005.
Copeland, S.M., Davies, K.W., Boyd, C.S. 2024. Sagebrush ecosystems are more than Artemisia: The complex issue of degraded understories in the Great Basin. Rangeland Ecology and Management. 94:184-194. https://doi.org/10.1016/j.rama.2024.03.007.
Holfus, C.M., Boyd, C.S., Rios, R.C., Davies, K.W., Copeland, S.M., Mata-Gonzalez, R. 2023. Wyoming big sagebrush transplant survival and growth affected by age, season of planting, and competition. Rangeland Ecology and Management. 92:1-11. https://doi.org/10.1016/j.rama.2023.09.005.
O'Connor, R.C., Fox, V.G., Hamerlynck, E.P. 2024. Photosynthetic resilience of Elymus elymoides and Pseudoroegneria spicata seedlings following acute water stress. Rangeland Ecology and Management. 94:195-198. https://doi.org/10.1016/j.rama.2024.03.012.
Davies, K.W., Boyd, C.S., Svejcar, L.N., Clenet, D.R. 2023. Long-term effects of revegetation efforts in annual grass-invaded rangeland. Rangeland Ecology and Management. 92:59-67. https://doi.org/10.1016/j.rama.2023.10.001.
Davies, K.W., Bates, J.D., Boyd, C.S. 2023. Is crested wheatgrass invasive in sagebrush steppe with intact understories in the Great Basin? Rangeland Ecology and Management. 90:322-328. https://doi.org/10.1016/j.rama.2023.03.004.
Smith, J.T., Allred, B.W., Boyd, C.S., Davies, K.W., Kleinhesselink, A.R., Morford, S.L., Naugle, D.E. 2023. Fire needs annual grasses more than annual grasses need fire. Biological Conservation. 286. Article 110299. https://doi.org/10.1016/j.biocon.2023.110299.
Case, M.F., Davies, K.W., Boyd, C.S., Aoyama, L., Merson, J., Penkauskas, C., Hallet, L.M. 2024. Cross-scale analysis reveals interacting predictors of annual and perennial cover in Northern Great Basin rangelands. Ecological Applications. 34(4). Article e2953. https://doi.org/10.1002/eap.2953.