Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Dabney Hall, 1416 Circle Dr, Knoxville, TN, 37996, USA.
Sci Rep. 2023 Feb 16;13(1):2817. doi: 10.1038/s41598-023-29564-2.
Climate-induced evolution will determine population persistence in a changing world. However, finding natural systems in which to study these responses has been a barrier to estimating the impact of global change on a broad scale. We propose that isolated sky islands (SI) and adjacent mountain chains (MC) are natural laboratories for studying long-term and contemporary climatic pressures on natural populations. We used greenhouse common garden trees to test whether populations on SI exposed to hot and dry climates since the end of the Pleistocene have phenotypically diverged from populations on MC, and if SI populations have converged in these traits. We show: (1) populations of Populus angustifolia from SI have diverged from MC, and converged across SI, in reproductive and productivity traits, (2) these traits (cloning and aboveground biomass, respectively) are significantly correlated, suggesting a genetic linkage between them, and (3) the trait variation is driven by both natural selection and genetic drift. These shifts represent potentially beneficial phenotypes for population persistence in a changing world. These results suggest that the SI-MC comparison is a natural laboratory, as well as a predictive framework, for studying long-term responses to climate change across the globe.
气候引起的进化将决定物种在变化世界中的生存能力。然而，寻找可以研究这些反应的自然系统一直是评估全球变化对广泛范围影响的障碍。我们提出，孤立的天空岛屿（SI）和相邻的山脉（MC）是研究自然种群长期和当代气候压力的天然实验室。我们使用温室常见的园林树木来测试自更新世末期以来暴露在炎热和干燥气候下的 SI 上的种群是否在表型上与 MC 上的种群发生了分歧，如果 SI 上的种群在这些特征上是否趋同。我们发现：（1）来自 SI 的 Populus angustifolia 种群在繁殖和生产力特征上与 MC 种群发生了分歧，并在 SI 内趋同；（2）这些特征（分别是克隆和地上生物量）显著相关，表明它们之间存在遗传联系；（3）这些特征的变异是由自然选择和遗传漂变共同驱动的。这些变化代表了在变化的世界中种群生存的潜在有益表型。这些结果表明，SI-MC 比较既是研究全球气候变化长期响应的天然实验室，也是预测框架。
