Ascensão Fernando, Mata Cristina, Malo Juan E, Ruiz-Capillas Pablo, Silva Catarina, Silva André P, Santos-Reis Margarida, Fernandes Carlos
CE3C - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Ed C2-5° piso, Lisboa, Portugal.
Terrestrial Ecology Group, Departamento de Ecología, Universidad Autónoma de Madrid, Madrid, Spain.
PLoS One. 2016 Mar 15;11(3):e0151500. doi: 10.1371/journal.pone.0151500. eCollection 2016.
Road barrier effect is among the foremost negative impacts of roads on wildlife. Knowledge of the factors responsible for the road barrier effect is crucial to understand and predict species' responses to roads, and to improve mitigation measures in the context of management and conservation. We built a set of hypothesis aiming to infer the most probable cause of road barrier effect (traffic effect or road surface avoidance), while controlling for the potentially confounding effects road width, traffic volume and road age. The wood mouse Apodemus sylvaticus was used as a model species of small and forest-dwelling mammals, which are more likely to be affected by gaps in cover such as those resulting from road construction. We confront genetic patterns from opposite and same roadsides from samples of three highways and used computer simulations to infer migration rates between opposite roadsides. Genetic patterns from 302 samples (ca. 100 per highway) suggest that the highway barrier effect for wood mouse is due to road surface avoidance. However, from the simulations we estimated a migration rate of about 5% between opposite roadsides, indicating that some limited gene flow across highways does occur. To reduce highway impact on population genetic diversity and structure, possible mitigation measures could include retrofitting of culverts and underpasses to increase their attractiveness and facilitate their use by wood mice and other species, and setting aside roadside strips without vegetation removal to facilitate establishment and dispersal of small mammals.
道路屏障效应是道路对野生动物最主要的负面影响之一。了解造成道路屏障效应的因素对于理解和预测物种对道路的反应，以及在管理和保护背景下改进缓解措施至关重要。我们构建了一组假设，旨在推断道路屏障效应最可能的原因（交通效应或路面回避），同时控制道路宽度、交通量和道路使用年限等潜在混杂效应。林姬鼠被用作小型森林栖息哺乳动物的模型物种，这类物种更容易受到诸如道路建设导致的植被覆盖间隙的影响。我们对比了三条高速公路样本中道路两侧相对和同侧的遗传模式，并使用计算机模拟来推断道路两侧之间的迁移率。来自302个样本（每条高速公路约100个）的遗传模式表明，高速公路对林姬鼠的屏障效应是由于路面回避。然而，通过模拟我们估计道路两侧之间的迁移率约为5%，这表明确实存在一些有限的跨高速公路基因流动。为了减少高速公路对种群遗传多样性和结构的影响，可能的缓解措施包括改造涵洞和地下通道，以增加其吸引力并便于林姬鼠和其他物种使用，以及留出路边地带不进行植被清除，以促进小型哺乳动物的定居和扩散。
