Mead Alayna, Fitz-Gibbon Sorel, Knapp John, Sork Victoria L
Department of Ecology and Evolutionary Biology University of California, Los Angeles Los Angeles California USA.
Department of Ecosystem Science and Management Pennsylvania State University University Park Pennsylvania USA.
Evol Appl. 2024 Dec 18;17(12):e70057. doi: 10.1111/eva.70057. eCollection 2024 Dec.
Management strategies, such as assisted gene flow, can increase resilience to climate change in tree populations. Knowledge of evolutionary history and genetic structure of species are needed to assess the risks and benefits of different strategies. , or Island Oak, is a rare oak restricted to six Channel Islands in California, United States, and Baja California, Mexico. Previous work has shown that Island Oaks on each island are genetically differentiated, but it is unclear whether assisted gene flow could enable populations to tolerate future climates. We performed whole-genome sequencing on Island Oak individuals and , a closely related species that hybridizes with Island Oak (127 total), to characterize genetic structure and introgression across its range and assess the relationship between genomic variation and climate. We introduce and assess three potential management strategies with different trade-offs between conserving historic genetic structure and enabling populations to survive changing climates: the status quo approach; ecosystem preservation approach, which conserves the trees and their associated biodiversity; and species preservation approach, which conserves the species. We compare the impact of these approaches on predicted maladaptation to climate using Gradient Forest. We also introduce a climate suitability index to identify optimal pairs of seed sources and planting sites for approaches involving assisted gene flow. We found one island (Santa Rosa) that could benefit from the ecosystem preservation approach and also serve as a species preservation site. Overall, we find that both the ecosystem and species preservation approaches will do better than the status quo approach. If preserving Island Oak ecosystems is the goal, assisted dispersal into multiple sites could produce adapted populations. If the goal is to preserve a species, the Santa Rosa population would be suitable. This case study both illustrates viable conservation strategies for Island Oak and introduces a framework for tree conservation.
诸如辅助基因流动等管理策略，可以提高树木种群对气候变化的恢复力。需要了解物种的进化历史和遗传结构，才能评估不同策略的风险和益处。海岛栎，即矮栎，是一种珍稀栎树，仅分布于美国加利福尼亚州的六个海峡群岛以及墨西哥下加利福尼亚州。此前的研究表明，每个岛屿上的海岛栎在基因上存在差异，但尚不清楚辅助基因流动是否能使种群耐受未来的气候。我们对海岛栎个体以及与海岛栎杂交的近缘物种（共127个）进行了全基因组测序，以描绘其分布范围内的遗传结构和基因渗入情况，并评估基因组变异与气候之间的关系。我们提出并评估了三种潜在的管理策略，这些策略在保护历史遗传结构和使种群能够在不断变化的气候中生存之间存在不同的权衡：现状方法；生态系统保护方法，即保护树木及其相关的生物多样性；以及物种保护方法，即保护物种。我们使用梯度森林比较了这些方法对预测的气候适应性不良的影响。我们还引入了一个气候适宜性指数，以确定涉及辅助基因流动的方法中种子来源和种植地点的最佳组合。我们发现一个岛屿（圣罗莎岛）可以从生态系统保护方法中受益，并且还可以作为物种保护地点。总体而言，我们发现生态系统和物种保护方法都将比现状方法效果更好。如果目标是保护海岛栎生态系统，向多个地点进行辅助扩散可以培育出适应环境的种群。如果目标是保护一个物种，圣罗莎岛的种群将是合适的。这个案例研究既说明了海岛栎可行的保护策略，也引入了一个树木保护框架。
