Common-garden experiments, in which plants sourced from geographically distant populations are grown together such that genetic differences may be expressed, can provide insight on adaptive variation of sagebrush.
However, the spatial scale at which population differentiation occurs is rarely addressed, leaving a critical information gap for informing seed-transfer guidelines and assessing species’ climate vulnerability. USGS researchers compared the survival, growth, and reproductive effort of three intermediate-elevation populations of Wyoming big sagebrush planted in gardens along an elevational gradient over three growing seasons. Substantial variation was observed between gardens in survival, foliar crown volume, and reproductive effort, but not among the three transplanted populations. Results suggest that site-specificity in adaptation can occur at finer scales than is accounted for in empirical seed-transfer guidance when the guidance is derived from broadscale common-garden studies. Findings also offer a possible explanation for the lack of successful establishment following many historical Wyoming big sagebrush seedings.
Germino, M.J., Davidson, B.E., 2020, Spatial grain of adaptation is much finer than ecoregional-scale common gardens reveal: Ecology and Evolution, p. online, https://doi.org/10.1002/ece3.6651.