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.

非生物与生物条件在整个景观中通常呈连续变化，对当地种群施加了差异化选择压力。我们采用种源试验（provenance trial）方法，研究了落基山脉本土多年生十字花科草本植物直立硬毛荠（Boechera stricta）的局域适应微地理变异。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，使得相邻种群面临不同的选择压力。我们采集了南部（科罗拉多州）与北部（爱达荷州）种群的种质材料，通过微卫星标记（microsatellite markers）分析了遗传相似性的空间变异特征。随后，我们将多个当地种群的基因型材料移栽至两个区域的同质园（common garden）中开展试验。多项适合度（fitness）组分均呈现出局域适应的连续变异特征。在爱达荷州的同质园内，源自温暖生境（低海拔或南向坡地）的基因型材料对北向坡地同质园的适应性较差。在科罗拉多州的高海拔与低海拔同质园中，对昆虫取食的易感程度随种源海拔升高而增加。在科罗拉多州高海拔同质园中，种源海拔与该同质园海拔相近的基因型的萌发成功率达到峰值，而源自更高或更低海拔的基因型的萌发成功率则随之下降。我们还在科罗拉多州低海拔同质园中发现了存活与繁殖力（fecundity）这两个适合度组分存在局域适应不良（maladaptation）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。