Context

The natural patchiness of wetlands and flooding events are likely to strongly affect the genetic structure of their terrestrial species. However, these effects are not well understood yet, especially for small mammals.

Objectives

We investigated at different spatial scales the genetic structure of the harvest mouse (Micromys minutus), a threatened small mammal strongly tied to wetlands, and the effects on gene flow of flooding and of the different types of landscape elements composing a wetland.

Methods

309 harvest mice were sampled in eight sites in Western Europe. Their genetic structure and diversity at 15 microsatellite loci were analyzed at a regional spatial scale and at a local scale, where the resistance of land cover and flooding to gene flow was also assessed, with the optimization procedure implemented in ResistanceGA.

Results

At a regional scale, our study revealed a strong genetic differentiation between populations from Northern Europe to the Mediterranean Sea. At the local scale, in a flooded wetland in France, the species exhibited a large genetic cluster over at least 45 km², in spite of a large river crossing it. Winter floods explained genetic structure better than landscape features alone, with a stronger resistance to gene flow in reed beds where vegetation level above water was high: contrary to meadows, from which individuals are forced to escape, reed beds can be “golden prisons”, i.e. refuges during floods but with very low possibility of movements.

Conclusions

Several parameters influencing the functioning of a flooded population of harvest mouse are here highlighted that can also be useful for the development of plans to safeguard wetland ecosystems.

中文翻译：

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景观特征和洪水对小型湿地啮齿动物收获小鼠（Micromys minutus）遗传结构的影响

语境

湿地的自然斑块和洪水事件很可能强烈影响其陆地物种的遗传结构。然而，这些作用还没有被很好地理解，特别是对于小型哺乳动物。

目标

我们在不同的空间尺度上研究了收获小鼠（Micromys minutus）的遗传结构，它是一种与湿地紧密相连的受威胁的小型哺乳动物，并且对洪水和构成湿地的不同类型景观元素对基因流的影响。

方法

在西欧的八个地点采样了309只收获小鼠。在一个区域空间尺度和一个局部尺度上分析了它们在15个微卫星基因座上的遗传结构和多样性，并通过在ResistanceGA中实施的优化程序评估了土地覆盖和洪水对基因流的抵抗力。

结果

在区域范围内，我们的研究表明，从北欧到地中海的种群之间存在很强的遗传分化。在法国，一个被洪水淹没的湿地，尽管有大量河流穿越该物种，但该物种在至少45 km ²上仍表现出巨大的遗传簇。冬季洪水比单独的景观特征更好地解释了遗传结构，在水位以上植被较高的芦苇床上对基因流的抵抗力更强：与草地被迫逃离的草甸相反，芦苇床上可能是“黄金监狱”，即在洪水期间避难，但活动的可能性很小。

结论

这里重点介绍了影响收获老鼠淹水种群功能的几个参数，这些参数对于制定保护湿地生态系统的计划也很有用。