An endangered arboreal specialist, the western ringtail possum (Pseudocheirus occidentalis), shows a greater genetic divergence across a narrow artificial waterway than a major road

The fragmentation of habitats by roads and other artificial linear structures can have a profound effect on the movement of arboreal species due to their strong fidelity to canopies. Here, we used 12 microsatellite DNA loci to investigate the fine-scale spatial genetic structure and the effects of a major road and a narrow artificial waterway on a population of the endangered western ringtail possum (Pseudocheirus occidentalis) in Busselton, Western Australia. Using spatial autocorrelation analysis, we found positive genetic structure in continuous habitat over distances up to 600 m. These patterns are consistent with the sedentary nature of P. occidentalis and highlight their vulnerability to the effects of habitat fragmentation. Pairwise relatedness values and Bayesian cluster analysis also revealed significant genetic divergences across an artificial waterway, suggesting that it was a barrier to gene flow. By contrast, no genetic divergences were detected across the major road. While studies often focus on roads when assessing the effects of artificial linear structures on wildlife, this study provides an example of an often overlooked artificial linear structure other than a road that has a significant impact on wildlife dispersal leading to genetic subdivision.

道路与其他人工线性设施所造成的生境破碎化，会对树栖物种的移动产生深远影响——这类物种对树冠具有极强的依附性。本研究采用12个微卫星DNA（microsatellite DNA）位点，针对澳大利亚西部巴斯尔顿（Busselton）境内的濒危西部环尾袋貂（Pseudocheirus occidentalis）种群，开展精细尺度空间遗传结构分析，并探究一条主干道与一处狭窄人工水道对该种群的影响。通过空间自相关分析，我们发现连续生境内距离达600米的范围内存在正遗传结构。该结果与西部环尾袋貂的定居性特征一致，同时凸显了其对生境破碎化效应的脆弱性。成对亲缘关系值与贝叶斯聚类分析同样显示，人工水道两侧存在显著遗传分化，表明该水道构成了基因流的屏障。与之形成鲜明对比的是，主干道两侧未检测到任何遗传分化。尽管现有相关研究在评估人工线性设施对野生动物的影响时，往往将焦点置于道路之上，但本研究揭示了一类常被忽视的非道路类人工线性结构——其可对野生动物扩散造成显著影响，进而引发遗传分化。