Data from: Microgeographic patterns of genetic divergence and adaptation across environmental gradients in Boechera stricta (Brassicaceae)

Abiotic and biotic conditions often vary continuously across the landscape, imposing divergent selection on local populations. We used a provenance trial approach to examine microgeographic variation in local adaptation in Boechera stricta (Brassicaceae), a perennial forb native to the Rocky Mountains. In montane ecosystems, environmental conditions change considerably over short spatial scales, such that neighboring populations can be subject to different selective pressures. Using accessions from southern (Colorado) and northern (Idaho) populations, we characterized spatial variation in genetic similarity via microsatellite markers. We then transplanted genotypes from multiple local populations into common gardens in both regions. Continuous variation in local adaptation emerged for several components of fitness. In Idaho, genotypes from warmer environments (low elevation or south facing sites) were poorly adapted to the north-facing garden. In high and low elevation Colorado gardens, susceptibility to insect herbivory increased with source elevation. In the high elevation Colorado garden, germination success peaked for genotypes that evolved at similar elevations as the garden, and declined for genotypes from higher and lower elevations. We also found evidence for local maladaptation in survival and fecundity components of fitness in the low elevation Colorado garden. This approach is a necessary first step in predicting how global change could affect evolutionary dynamics.

非生物与生物条件往往在景观中呈连续变化，对当地种群施加了分化选择压力。本研究采用种源试验法，探究了落基山脉本土多年生草本植物Boechera stricta（十字花科 Brassicaceae）的局部适应微地理变异。在山地生态系统中，环境条件在较短空间尺度内便会发生显著改变，使得相邻种群承受不同的选择压力。我们使用采自南部（科罗拉多州）与北部（爱达荷州）种群的种质资源，通过微卫星标记（microsatellite markers）刻画了遗传相似性的空间变异模式。随后，我们将多个当地种群的基因型材料移栽至两个研究区域内的同质园（common garden）中。多个适合度组分均呈现出局部适应的连续变异特征：在爱达荷州的同质园中，源自温暖生境（低海拔或南向坡地）的基因型材料对北向园的适应能力较差；在科罗拉多州的高、低海拔同质园中，对昆虫植食为害的易感性随源种群海拔升高而增强；在科罗拉多州高海拔同质园中，基因型材料的发芽成功率在其源种群海拔与试验园海拔相近时达到峰值，而源自更高或更低海拔的材料则表现出发芽成功率下降的趋势。此外，我们还在科罗拉多州低海拔同质园中发现了适合度相关的存活与繁殖力组分存在局部适应不良的证据。该研究方法是预测全球变化如何影响进化动态的必要前置步骤。