Data from: Climate at the local and landscape level drive adaptive genetic responses associated with survival in big sagebrush (Artemisia tridentata)

A genecological approach was used to explore genetic variation for survival in Artemisia tridentata (big sagebrush). Artemisia tridentata is a widespread and foundational shrub species in western North America. This species has lost much of its historic range, to the detriment of dependent wildlife, and efforts to restore it are now a land management priority. Common garden experiments were established at three sites with seedlings from 55 source-populations. Populations included each of the three predominant subspecies, and cytotype variations. Survival was monitored for five-years to assess differences in survival between gardens and populations. We found evidence of adaptive genetic variation for survival. Survival within gardens differed by source-population and a large proportion of this variation was explained by seed climate-of-origin. Plants from areas with the coldest winters had the highest levels of survival, while populations from warmer and drier sites had the lowest levels of survival. Survival was lowest, 36%, in the garden that was prone to the lowest minimum temperatures. These results suggest the importance of topography on microclimate variations and their affect on survival. Understanding how genetic variation is arrayed across the landscape and its association with climate can greatly enhance the success of restoration and conservation.

本研究采用基因生态学方法，探究了三齿蒿（Artemisia tridentata，俗称大蒿）的存活相关遗传变异。三齿蒿是北美西部广泛分布的关键建群灌木物种。当前该物种的历史分布区已大幅缩减，对依赖其生存的野生动物造成不利影响，因此开展三齿蒿恢复工作现已成为土地管理的优先事项。研究人员在3个试验点设立了同质园（common garden）试验，供试材料为来自55个源种群的实生苗。这些源种群涵盖了该物种3个主要亚种的全部类群，同时包含细胞型（cytotype）变异。本研究对供试植株的存活情况进行了为期5年的监测，以评估不同试验点及不同源种群间的存活差异。研究发现了与存活相关的适应性遗传变异的证据：各试验点内的植株存活率因源种群不同存在显著差异，其中大部分变异可由种子采集地的气候条件解释。冬季气温最低的源产地种群的植株存活率最高，而来自温暖干旱生境的种群存活率最低。在最低温易达极值的试验点，植株存活率最低，仅为36%。上述结果表明，地形对微气候变异的调控作用及其对植株存活的影响至关重要。明晰遗传变异在景观尺度上的分布格局及其与气候的关联，可大幅提升三齿蒿恢复与保护工作的成效。