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.

非生物与生物条件常在景观尺度上呈连续变化，对本地种群施加歧化选择压力。本研究采用种源试验法，对原生分布于落基山脉的多年生草本植物硬毛南芥（Boechera stricta，十字花科（Brassicaceae））的本地适应微地理变异展开探究。在山地生态系统中，环境条件在极小的空间尺度内便会发生显著变化，相邻种群因此可能面临迥异的选择压力。本研究采集来自南部（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）对遗传相似性的空间变异进行了表征。随后将多个本地种群的基因型材料移植至两个研究区域内的同质园（common garden）中。多项适合度组分均呈现出本地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圃的适配性较差。在科罗拉多州的高海拔与低海拔同质园中，昆虫植食易感性随种源海拔升高而增强。在科罗拉多州高海拔同质园中，发芽成功率在种源海拔与园圃海拔相近的基因型中达到峰值，而源自更高或更低海拔的基因型的发芽成功率则随之下降。此外，在科罗拉多州低海拔同质园中，我们发现了适合度相关的存活与繁殖力组分存在本地适应不良的证据。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。