Roads and other linear infrastructure create treeless gaps that can limit the movement of non-flying, arboreal animals. These negative effects are particularly strong in dense forests, where even narrow infrastructure corridors represent a significant change in habitat structure. Artificial canopy bridges are an increasingly common approach to mitigating the barrier effect of roads and other linear infrastructure on the movement of arboreal mammals; however, questions remain about the success of various designs for different species. Here we conduct an experimental evaluation of the response of a critically endangered possum, Leadbeater's Possum (Gymnobelideus leadbeateri), to two artificial canopy bridge designs: single-rope bridges and ladder bridges. We found that both bridges were used by Leadbeater's Possum and five other species of arboreal marsupial to cross narrow, forestry roads. However, Leadbeater's Possums crossed ladder bridges 13 times more often than the single-rope design (average of 564.5 and 41.75 crossings per design respectively). Radiotelemetry conducted on four Leadbeater's Possums prior to bridge installation detected no road crossings, providing preliminary evidence that the bridges improved cross-road movement. Ladder bridges appear to be the better design choice for a wider range of arboreal marsupials as they were used more frequently, offer greater stability, and provide better predator avoidance than single-rope designs.

中文翻译：

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减轻线性基础设施对茂密森林中树栖哺乳动物的影响：树冠桥试验

道路和其他线性基础设施形成了没有树木的空隙，限制了不会飞的树栖动物的活动。这些负面影响在茂密的森林中尤为强烈，即使是狭窄的基础设施走廊也代表着栖息地结构的重大变化。人工树冠桥是一种越来越普遍的方法，可以减轻道路和其他线性基础设施对树栖哺乳动物移动的屏障作用；然而，关于针对不同物种的各种设计是否成功的问题仍然存在。在这里，我们对极度濒危的负鼠 Leadbeater's Possum ( Gymnobelideus leadbeateri)的反应进行了实验评估), 到两种人造树冠桥设计：单索桥和阶梯桥。我们发现这两座桥都被 Leadbeater 的负鼠和其他五种树栖有袋动物用来穿越狭窄的林间道路。然而，Leadbeater 的负鼠穿过梯桥的次数是单绳设计的 13 倍（每个设计的平均次数分别为 564.5 次和 41.75 次）。在安装桥梁之前对四只 Leadbeater 负鼠进行的无线电遥测没有检测到道路交叉口，这提供了初步证据表明桥梁改善了十字路口的移动。对于范围更广的树栖有袋动物，梯桥似乎是更好的设计选择，因为它们使用更频繁，稳定性更高，并且比单绳设计更能避免捕食者。