Testing the Efficacy of Seed Zones of Bluebunch Wheatgrass (2013)

Testing the Efficacy of Seed Zones for Re-Establishment and Adaptation of Bluebunch Wheatgrass (Pseudoroegneria spicata) (2013)


Investigators and Affiliations

  • Francis Kilkenny, Ph.D., Research Biologist, USDA Forest Service, Rocky Mountain Research Station, Boise, ID
  • Brad St. Clair, Ph.D., Research Geneticist, USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR



  • USDA Forest Service Rocky Mountain Research Station
  • USDA Forest Service Pacific Northwest Research Station
  • USDA Forest Service National Fire Plan
  • USDI BLM/USDA Forest Service Great Basin Native Plant Program


Background: Previous genecological research funded by the Great Basin Native Plant Project found that bluebunch wheatgrass populations differed in traits important for adaptation to drought and cold. Based on results of that study, seed zones were delineated for the interior northwest including the Great Basin, Snake River Plain, Columbia Plateau, and Blue Mountains. This study tests the efficacy of seed zones delineated in the previous study for differences in re-establishment and adaptation of bluebunch wheatgrass populations from local seed zones compared to climatically distant seed zones with the hypothesis that local sources will show better establishment as well as better survival, growth and reproduction in the long-term.


This study will test the efficacy of recently delineated seed zones for bluebunch wheatgrass for ensuring successful re-establishment and long-term adaptation, and maintaining genetic diversity, of this ecologically important restoration species with current and future value for use in INL Site seedings. The study will also explore the consequences of changing climates for adaptation by substituting space for time to evaluate different populations in different climates. Long-term productivity and adaptation will be modeled to allow evaluation of trade-offs between different management options for current and future climates. Population movement guidelines and associated seed zones can be adjusted based on results from this study and management objectives.



  • Evaluate adaptation (establishment, survival, growth and reproduction over time) of bluebunch wheatgrass (Pseudoroegneria spicata) populations from local seed zones relative to distant seed zones.
  • Model adaptation as a function of the climates of source locations and test sites.
  • Characterize traits and climates important for adaptation.
  • Model effects of climate change on native populations and the consequences of assisted migration for responding to climate change.

Accomplishments through 2013:

To test this hypothesis, seed was collected from five populations in each of eight seed zones in each of two broad regions. Plants from each seed zone will be planted back into a single test site representative of the climate of each of the eight seed zones in a region. We delineated the two broad regions as (1) a transect from the hot, dry climates of the lower Snake River Plain to the cool, somewhat wet climates of the transverse ranges of the Great Basin to the cold, dry climates of the upper Snake River Plain (INL Site) and (2) a transect from the hot, dry climates of the Columbia Plateau to the cool, wet climates of the Blue Mountains to the cold, dry climates east of the Blue Mountains. In addition to populations from each seed zone, two widely used varieties will be included at each test site.

We made seed collections from 138 populations from throughout the two broad regions in summer 2013. From these, 78 populations were chosen for inclusion in the study based on their distribution within each of the seed zones and the amount of available seed (only four populations, not five, were available from the hottest, driest seed zone within each transect). Included were collections from S Transect Seed Zone 2a, which is centered over the INL Site. All seed has been cleaned, tested for germination, and is ready for sowing. The University of Idaho has been contracted to produce the containerized planting stock for the study. Potential collaborators were contacted during the past winter to help with providing test sites on their lands.

Plans for Continuation: Test sites will be finalized in spring 2014, including one on or near the INL Site and any necessary site preparation will be done over the summer. Planting stock will be grown over the summer. Test sites will be planted in fall 2014 beginning with the higher elevation sites in early September and ending with the lower elevation sites in October or November. The experimental design at each of the eight test sites per transect will be a split-plot design with a plot represented by 25 plants from each seed zone and the subplots being five populations per seed zone. Each site will include five replications. Planting spacing will be 0.5 m between plants. Plans are to measure the sites every year for an indefinite length of time, but with early results presented after two growing seasons. The primary variables of interest are cover and biomass of bluebunch wheatgrass on each seed zone plot over time, but survival, plant height, crown diameter, and biomass of individual plants of each population is also of great interest. Cover and biomass of competing vegetation in each plot will also be measured.

Publications, Theses, Reports:


  • Kilkenny, F., B. St. Clair, M. Horning. 2013. Climate change and the future of seed zones, 87-89. In: D. Haase, J. Pinto, K. Wilkinson, technical coordinators. National Proceedings: Forest and Conservation Nursery Associations—2012. RMRS-P-69. USDA Forest Service, Fort Collins, CO.
  • St.Clair, J. B., F. F. Kilkenny, R. C. Johnson, N. L. Shaw, G. Weaver, George. 2013. Geneticvariation in adaptive traits and seed transfer guidelines for Pseudoroegneria spicata (bluebunch wheatgrass) in the northwestern United States. Evolutionary Applications 6:933-948.

  • Kilkenny, F. F., and J. B. St. Clair. 2013. Testing the efficacy of seed Zones for re-establishment and adaptation of bluebunch wheatgrass (Pseudoroegneria spicata). Great Basin Native Plant Project 2013 Annual Report. USDA Forest Service, Rocky Mountain Research Station, Boise, ID.

  • Kilkenny, F. F. 2013. Characterization of current and future climates within and among seed zones to evaluate options for adapting to climate change. Second National Native Seed Conference, Santa Fe, NM, April 8-11, 2013.
  • St. Clair, J. B., F. F. Kilkenny, R. C. Johnson. 2013. Adaptation of native grasses to climates of the interior western United States. Second National Native Seed Conference, April 8-11, 2013.