DISTURBANCE ASSESSMENT AND MITIGATION OF GREAT BASIN RANGELAND
Location: Watershed Management Research
Title: Hydrothermal indices for classification of seedbed microclimate
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2010
Publication Date: February 6, 2011
Citation: Hardegree, S.P., Cho, J., Roundy, B., Moffet, C., Jones, T.A., James, J.J., Shaw, N., Cox, R. 2011. Hydrothermal indices for classification of seedbed microclimate. In: Abstracts of the 64th Annual Meeting, Society for Range Management, Billings, MT, Feb 6-10, 2011 (CD-ROM Abstract).
The microclimatic requirements for successful establishment of rangeland species are much more restrictive than those required for maintenance of mature plant communities. We used a 45-year weather record to parameterize a seedbed-microclimate model for estimation of hourly temperature and moisture at seeding depth for three soil types at the Orchard Field Test Site in southwestern Ada County, Idaho. Hydrothermal-germination response was measured in the laboratory for multiple seedlots of cheatgrass, bluebunch wheatgrass, bottlebrush squirreltail, Sandberg bluegrass, thickspike wheatgrass, Idaho fescue and sagebrush. Germination response models were developed to estimate potential germination rate for every hour of the entire seedbed simulation period. Seedbed microclimate was assessed for each month, year, and season and for each site and seedlot by integrating germination rate estimates into an ecological index of relative favorability for initial germination and growth. This index showed consistent patterns among seedlots for different years, and provides a relatively sensitive index for interpreting favorability of seedbed microclimate among diverse and variable weather conditions. This index could be combined with field data to define minimum weather thresholds for successful establishment of alternative plant materials; in conjunction with weather forecast models for making restoration and fire-rehabilitation management decisions for dormant-fall planting; and evaluation of potential climate-change impacts on plant community trajectories and future restoration/rehabilitation management scenarios.