Context

Environmental changes produce discontinuities in suitable habitat. However, drawing inference into the effects of these changes on contemporary genetic patterns is often difficult. Recent approaches for evaluating landscape resistance facilitate increased understanding of landscape effects on gene flow.

Objectives

We investigated the effects of pluvial lakes and sagebrush cover on genetic connectivity for the pygmy rabbit (Brachylagus idahoensis), a sagebrush obligate species. We predicted that sagebrush-based surfaces would be more explanatory than pluvial lake surfaces. Furthermore, we predicted that habitat characteristics during the mid-Holocene would explain genetic differentiation better than those during the late-Pleistocene.

Methods

We leveraged a genetic dataset to evaluate the explanatory power of landscape resistance surfaces. We generated resistance surfaces that represent varying degrees of resistance associated with pluvial lakes and sagebrush cover, then projected sagebrush distribution back to the mid-Holocene and late-Pleistocene.

Results

Representations based on sagebrush distribution were more explanatory than those based on pluvial lakes. Projections of sagebrush distribution back in time indicate concordance between genetic connectivity and mid-Holocene sagebrush distribution. Limited numbers of dispersal pathways were apparent among study regions, suggesting spatially restricted corridors of connectivity.

Conclusions

We demonstrate that shifts in vegetative cover can shape contemporary patterns of genetic connectivity. By coupling testing of resistance surfaces with estimates of past vegetative change, we provide insights into the time scales over which genetic differentiation may occur. Given projections of future declines in sagebrush, maintaining sagebrush cover will be critical to population persistence of pygmy rabbits.

中文翻译：

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全新世时代的景观条件影响山艾树专性物种侏儒兔（Brachylagus idahoensis）的遗传连通性

上下文

环境变化会在合适的栖息地中产生不连续性。然而，推断这些变化对当代遗传模式的影响通常很困难。最近评估景观抗性的方法促进了对景观对基因流影响的理解。

目标

我们研究了雨洪湖和山艾树覆盖对山艾树专性物种侏儒兔 ( Brachylagus idahoensis )遗传连通性的影响。我们预测，基于山艾树的表面将比雨洪湖表面更具解释性。此外，我们预测全新世中期的栖息地特征比晚更新世期间的栖息地特征更能解释遗传分化。

方法

我们利用遗传数据集来评估景观阻力表面的解释力。我们生成了代表与雨洪湖和山艾树覆盖相关的不同程度阻力的阻力面，然后将山艾树分布预测回全新世中期和晚更新世。

结果

基于山艾树分布的表示比基于雨洪湖的表示更具解释性。对山艾树分布的及时预测表明遗传连通性与全新世中期山艾树分布之间存在一致性。研究区域之间的传播途径数量有限，这表明连通性走廊在空间上受到限制。

结论

我们证明植物覆盖的变化可以塑造当代的遗传连通性模式。通过将抗性表面的测试与过去营养变化的估计相结合，我们可以深入了解遗传分化可能发生的时间尺度。鉴于对未来山艾树数量下降的预测，保持山艾树覆盖对于侏儒兔的种群持久性至关重要。