Сlimate-induced treeline dynamics in the Ural Mountains: drivers, constraints, and the role of genetic adaptation

挑战：乌拉尔山脉的高架树木对工业变暖做出了积极的反应。如果持续的森林扩张与未来的全球变化保持同步，它将挤压大片原始的高山冻原栖息地，可能灭绝。然而，气候变化的速度可能会超过树木的生长速度。此外，适应不良和遗传连接性差的景观可能会限制当地人口的适应。因此，只有遗传调查结合树木生态学数据输入一个空间明确的模型，可以模拟性状适应将能够解开的重要因素，为树线迁移，并提供现实的预测未来的树线位置。（1）考虑到近几十年来的快速变暖，我们预计乌拉尔森林线的树木结构变化率将显著增加，但将取决于区域气候和当地场地条件之间的相互作用。(2)虽然种子传播在乌拉尔是足够的移动的，使树线迁移在长期的气候变化，遗传隔离是由占主导地位的短距离繁殖策略。因此，（3）主要由气候驱动的树线动态受到具有快速全球变暖所需特征的种群适应潜力的限制。方法：我们的项目将联合收割机分子和树木生态学分析结合起来，作为基于个体的模拟模型的输入。我们选择了6个永久海拔林线样带为主的落叶落叶松林在乌拉尔山脉。在新的调查中重新运行以前对树木位置和人口数据的评估，将允许进行时间序列分析，以描述正在进行的树线迁移。从树木生态学分析，我们将推断气候驱动因素和地图的空间格局的反应在乌拉尔山脉（WP 1）。我们将采样和基因型个体生长沿着样带和超越估计有效的种子传播通过亲子分析，景观连接，和群体遗传学（WP 2）。我们将进一步开发基于个人的空间显式模型LAVESI和模拟横断面覆盖过去的千年，以提高我们的理解和所涉及的过程，特别是性状适应的重要性，迁移反应。该模型将用于预测和评估人口动态和迁移率（WP 3）。最后，我们将综合我们对更现实的树线响应和可能后果的研究结果，为气候适应战略（WP 4）的辩论提供信息。研究团队：德国-俄罗斯研究团队将卓越的实地知识和长期树线监测数据与分子方法和基于个体的北极地区树木建模专业知识相结合。基于对气候影响和乌拉尔海拔树木适应过程的深刻理解，我们将为未来的森林反馈提供路线图。

Challenge: Elevational treelines in the Urals respond positively to industrial warming. If ongoing forest expansion keeps pace with future global change it will squeeze vast areas of pristine alpine tundra habitats, possibly to extinction. However, the rate of climate change may outrun a treeline advance. Furthermore, maladaptation and poor genetic connectivity in the landscape may constrain the adaptation of local populations. Hence, only a genetic survey in combination with dendroecological data fed into a spatially explicit model that can simulate trait adaptations will be able to unravel the important factors for treeline migration and provide realistic predictions of the future treeline position.Hypotheses: (1) Given the fast warming over recent decades, we expect the rate of structural changes in tree stands at the treeline in the Urals to increase significantly, but will depend on the interplay amongst regional climate and local site conditions. (2) Although seed dispersal in the Urals is sufficiently mobile to enable the treeline to migrate over long-term climate changes, genetic isolation is caused by dominant short-distance reproduction strategies. Consequently, (3) the primarily climate-driven treeline dynamics are constrained by the adaptation potential of populations with the traits necessary for rapid global warming.Approach: Our project will combine molecular and dendroecological analyses as inputs for an individual-based simulation model. We selected six permanent elevational treeline transects dominated by deciduous larch forests in the Urals. Rerunning previous assessments of tree position and population data in new surveys will allow time-series analyses to characterize the ongoing treeline migration. From the dendroecological analyses, we will infer climatic drivers and map spatial patterns of responses in the Urals (WP1). We will sample and genotype individuals growing along the transects and beyond to estimate effective seed dispersal via parentage analyses, landscape connectivity, and population genetics (WP2). We will further develop the individual-based spatially explicit model LAVESI and simulate transects covering past millennia to improve our understanding and the importance of the involved processes, especially trait adaptation, for migration responses. The model will be applied to forecast and evaluate population dynamics and migration rates (WP3). Finally, we will synthesise our findings of the more realistic treeline response and likely consequences to inform the debate on climate adaptation strategies (WP4).Research team: The German-Russian research team combines exceptional field knowledge and long-term treeline monitoring data with expertise in molecular methods and individual-based modelling of trees in Arctic regions.Expected impact: Based on a profound understanding of climate impacts and adaptation processes at elevational treelines in the Urals, we will deliver roadmaps for future forest feedbacks.