Abstract：
Gene flow can have rapid effects on adaptation and is an important evolutionary tool available when undertaking biological conservation and restoration. This tool is underused partly because of the perceived risk of outbreeding depression and loss of mean fitness when different populations are crossed. In this article, we briefly review some theory and empirical findings on how genetic variation is distributed across species ranges, describe known patterns of gene flow in nature with respect to environmental gradients, and highlight the effects of gene flow on adaptation in small or stressed populations in challenging environments (e.g., at species range limits). We then present a case study involving crosses at varying spatial scales among mountain populations of a trigger plant (Stylidium armeria: Stylidiaceae) in the Australian Alps to highlight how some issues around gene flow effects can be evaluated. We found evidence of outbreeding depression in seed production at greater geographic distances. Nevertheless, we found no evidence of maladaptive gene flow effects in likelihood of germination, plant performance (size), and performance variance, suggesting that gene flow at all spatial scales produces offspring with high adaptive potential. This case study demonstrates a path to evaluating how increasing sources of gene flow in managed wild and restored populations could identify some offspring with high fitness that could bolster the ability of populations to adapt to future environmental changes. We suggest further ways in which managers and researchers can act to understand and consider adaptive gene flow in natural and conservation contexts under rapidly changing conditions.
摘要：
基因流可以对适应产生快速影响，并且是进行生物保护和恢复时可用的重要进化工具。该工具未得到充分利用，部分原因是当不同种群杂交时，会出现远亲抑郁和平均健康损失的风险。在这篇文章中,我们简要回顾了一些关于遗传变异如何在物种范围内分布的理论和经验发现，描述自然界中已知的基因流动模式与环境梯度的关系，并强调基因流对挑战性环境中小型或应激人群适应的影响(例如，在物种范围限制下)。然后，我们提出了一个案例研究，涉及澳大利亚阿尔卑斯山触发植物（Stylidiumarmeria：Stylidiae）的山区种群之间不同空间尺度的杂交，以强调如何评估围绕基因流效应的一些问题。我们发现有证据表明，在更大的地理距离下，种子生产的远亲繁殖减弱。然而，我们没有发现适应不良基因流对发芽可能性的影响，工厂性能（尺寸），和性能差异，这表明在所有空间尺度上的基因流动都会产生具有高适应潜力的后代。本案例研究展示了一种方法，可以评估在管理的野生和恢复种群中增加的基因流来源如何识别出一些具有高适应性的后代，从而增强种群适应未来环境变化的能力。我们提出了进一步的方法，管理者和研究人员可以采取行动，在快速变化的条件下理解和考虑自然和保护环境中的适应性基因流动。
