Two different physiological mechanisms may contribute to cold hardiness, but it is not known if these adaptations have any drawbacks under warming conditions that relax selection pressures. USGS and USDA Forest Service scientists measured the winter and spring freezing responses for 14 populations of big sagebrush collected throughout its range. The relationships of the freezing responses to survival were evaluated in a warm common garden experiment, and in two colder gardens. Observed survivorship patterns relative to physiological thresholds suggest tradeoffs between freezing resistance and survival in warmer or wetter climates. Seeds have often been transferred from relatively cool origins to warmer restoration sites, and the findings describe a likely ecophysiological reason why these seedings have historically been less successful. Results may assist future sagebrush restoration efforts and provide insight on population responses to climate change.
 

Lazarus, B.E., Germino, M.J., Richardson, B., 2019, Freezing resistance, safety margins, and survival vary among big sagebrush populations across the western United States: American Journal of Botany, https://doi.org/DOI:10.1002/ajb2.1320