Skaien Cora L, Arcese Peter
Department of Forest and Conservation Sciences Faculty of Forestry University of British Columbia Vancouver British Columbia Canada.
Evol Appl. 2022 Apr 8;15(5):804-816. doi: 10.1111/eva.13371. eCollection 2022 May.
A capacity for rapid adaptation should enhance the persistence of populations subject to temporal and spatial heterogeneity in natural selection, but examples from nature remain scarce. () is a winter annual that exhibits local adaptation to browsing by ungulates and hypothesized to show context-dependent trade-offs in traits affecting success in competition versus resistance or tolerance to browsing. We grew P. congesta from 44 insular populations historically exposed or naïve to ungulates in common gardens to (1) quantify genetic, plastic and competitive effects on phenotype; (2) estimate a capacity for rapid adaptation (evolvability); and (3) test whether traits favoured by selection with ungulates present were selected against in their absence. Plants from browsed populations bolted and flowered later, had smaller inflorescences, were less fecund and half as tall as plants from naïve populations on average, replicating patterns in nature. Estimated evolvabilities (3-36%) and narrow-sense heritabilities (h2; 0.13-0.32) imply that differences in trait values as large as reported here can arise in 2-18 generations in an average population. Phenotypic plasticity was substantial, varied by browsing history and fruit phenotype and increased with competition. Fecundity increased with plasticity in flowering height given competition (0.47 ± 0.02 florets/cm, β ± se), but 23-77% faster in naïve plants bearing winged fruits (0.53 ± 0.04) than exposed-wingless plants (0.43 ± 0.03) or exposed-winged and naïve-wingless plants (0.30 ± 0.03, each case). Our results support the hypothesis that context-dependent variation in natural selection in . populations has conferred a substantial capacity for adaptation in response to selection in traits affecting success in competition versus resistance or tolerance to browsing in the absence versus presence of ungulates, respectively. Theory suggests that conserving adaptive capacity in . will require land managers to maintain spatial heterogeneity in natural selection, prevent local extinctions and maintain gene flow.
快速适应的能力应能增强在自然选择中面临时间和空间异质性的种群的持久性，但自然界中的实例仍然很少。（某植物）是一种冬季一年生植物，表现出对有蹄类动物啃食的局部适应性，并假设在影响竞争成功与对啃食的抗性或耐受性的性状上表现出依赖环境的权衡。我们在共同园地里种植了来自44个岛屿种群的（该植物），这些种群在历史上曾接触过或未曾接触过有蹄类动物，目的是：（1）量化对表型的遗传、可塑性和竞争效应；（2）估计快速适应能力（进化能力）；（3）测试在有蹄类动物存在时受选择青睐的性状在其不存在时是否会受到选择淘汰。来自有啃食历史种群的植株抽薹和开花较晚，花序较小，繁殖力较低，平均高度只有来自未接触过有蹄类动物种群植株的一半，这重现了自然界中的模式。估计的进化能力（3%-36%）和狭义遗传力（h2；0.13-0.32）表明，在平均种群中，如此大的性状值差异可能在2至18代内出现。表型可塑性很大，因啃食历史和果实表型而异，并随竞争而增加。在有竞争的情况下，繁殖力随开花高度的可塑性而增加（0.47±0.02朵小花/厘米，β±标准误），但在结有翅果实的未接触过有蹄类动物的植株（0.53±0.04）中，繁殖力的增加速度比接触过有蹄类动物的无翅植株（0.
