Data from: Evolutionary potential in the Alpine: trait heritabilities and performance variation of the dwarf willow Salix herbacea from different elevations and microhabitats

Alpine ecosystems are seriously threatened by climate change. One of the key mechanisms by which plants can adapt to changing environmental conditions is through evolutionary change. However, we still know little about the evolutionary potential in wild populations of long-lived alpine plants. Here, we investigated heritabilities of phenological traits, leaf size, and performance traits in natural populations of the long-lived alpine dwarf shrub Salix herbacea using relatedness estimates inferred from SSR (Simple Sequence Repeat) markers. Salix herbacea occurs in early- and late-snowmelt microhabitats (ridges and snowbeds), and we assessed how performance consequences of phenological traits and leaf size differ between these microhabitats in order to infer potential for evolutionary responses. Salix herbacea showed low, but significant, heritabilities of leaf size, clonal and sexual reproduction, and moderate heritabilities of phenological traits. In both microhabitats, we found that larger leaves, longer intervals between snowmelt and leaf expansion, and longer GDD (growing-degree days) until leaf expansion resulted in a stronger increase in the number of stems (clonal reproduction). In snowbeds, clonal reproduction increased with a shorter GDD until flowering, while the opposite was found on ridges. Furthermore, the proportion of flowering stems increased with GDD until flowering in both microhabitats. Our results suggest that the presence of significant heritable variation in morphology and phenology might help S. herbacea to adapt to changing environmental conditions. However, it remains to be seen if the rate of such an evolutionary response can keep pace with the rapid rate of climate change.

高山生态系统正遭受气候变化的严重威胁。植物适应环境条件变化的核心机制之一，便是通过演化改变实现适应。然而，学界对长寿高山植物野生种群的演化潜力仍所知甚少。本研究借助基于SSR（Simple Sequence Repeat，简单序列重复）标记的亲缘关系估计值，针对长寿高山矮灌木矮柳（Salix herbacea）的自然种群，分析了其物候性状、叶面积及适合度性状的遗传力。矮柳分布于融雪早期与融雪晚期两类微生境（山脊与雪床生境），本研究同时评估了物候性状与叶面积对个体适合度的影响在两类微生境间的差异，以此推断该物种的演化响应潜力。研究结果显示，矮柳的叶面积、克隆繁殖与有性繁殖的遗传力较低但显著，物候性状的遗传力则处于中等水平。在两类微生境中，更大的叶面积、融雪至展叶的间隔时长更长，以及展叶前的生长度日（GDD，growing-degree days）更高，均会使茎枝数量（克隆繁殖）的增长更为显著。在雪床生境中，开花前的生长度日越短，克隆繁殖越强；而山脊生境则呈现相反的趋势。此外，两类微生境中，开花茎枝的占比均随开花前生长度日的升高而增加。本研究表明，矮柳的形态与物候性状存在显著的可遗传变异，这或许能帮助其适应不断变化的环境条件。但这类演化响应的速率能否跟上气候变化的快速步伐，仍有待进一步探究。