Does rewilding improve ecosystem resilience?: a soundscape perspective

如果我们希望避免生物多样性崩溃和维持一个宜居的地球，理解为什么某些生态系统似乎比其他生态系统对扰动更有弹性是至关重要的。正在迅速向低强度、大规模、半被动的恢复方法转变，例如重新野生，这些方法寻求恢复生态过程，而不是提供预先确定的基于结构的结果。在整个重新野生的背景下，通过海狸的栖息地工程活动来利用海狸的恢复能力在英国变得越来越常见，大多数英国国家现在都有封闭的海狸项目，要么计划中，要么正在运作中，这在十年前是不可想象的。在苏格兰，约20年来，欧亚海狸再次出现在野外，它们的数量现在接近2000只，并计划将它们转移到更广泛的地方。从某种意义上讲，河狸筑坝和其他工程活动产生的生态效益很好，一系列研究表明鸟类、植物、两栖动物、无脊椎动物和蝙蝠的数量增加[1]。这些措施补充了河狸池塘拦截污染物、改善下游水质、减弱流量高峰和减轻干旱和野火干扰影响的能力[2]。然而，这一图景是不完整的，因为许多指示性生物分类群是孤立地研究的，而海狸的利益很可能不是均匀积累的，并且对周围的景观基质很敏感。水生系统对陆地系统的补贴程度以及这种补贴与海狸活动的关系如何变化，也仍然知之甚少，尽管当其他资源枯竭时，这种补贴对更高的营养水平具有潜在的重要性[3]。最后，尽管在极端事件面前，河狸池塘似乎提供了一种稳定的影响，但尚不清楚在增强种群、社区或生态系统功能方面是否伴随着生态效益。其中一些问题的解决仍然难以捉摸，部分原因是传统的监测方法具有侵入性，成本高昂，因此无法以所需的空间和时间频率进行部署。

Understanding why some ecosystems appear more resilient to perturbation than others isof fundamental importance if we wish to avoid biodiversity collapse and maintain ahabitable planet.There is a rapidly growing shift towards low intensity, large scale, semi-passiverestoration approaches, such as rewilding, that seek to restore ecological processesrather than deliver pre-defined structure-based outcomes. Within the overall context ofrewilding harnessing the restorative power of beavers through their habitat engineeringactivities is becoming increasingly commonplace in Britain, with most English countiesnow having enclosed beaver projects either planned or in operation, a situationunimaginable a decade ago. In Scotland Eurasian beavers have occurred again in thewild for about 20 years with their population now approaching 2000 animals and withplans to translocate them more widely. The ecological benefits that stem from dambuilding and the other engineering activities of beavers are, in some senses, wellestablished, with a catalogue of studies demonstrating increases in birds, plants,amphibians, invertebrates and bats [1]. These complement the ability of beaver ponds tointercept pollutants and improve downstream water quality, attenuate flow peaks andmitigate the disturbance effects of drought and wildfires [2]. However, the picture isincomplete since many indicator biological taxa are studied in isolation while the benefitsof beavers most likely do not accrue evenly and are sensitive to the surroundinglandscape matrix. The degree of subsidy from aquatic to terrestrial systems and how thisvaries in relation to beaver activity, also remains poorly understood, despite its potentialimportance to higher trophic levels when other resources are depleted [3]. Finally,although beaver ponds seem to provide a stabilising influence in the face of extremeevents, it is unknown whether there is an accompanying ecological benefit in terms ofenhanced resilience of populations, communities or ecosystem functions. The solution tosome of these questions has remained elusive in part because traditional monitoringapproaches are invasive and costly and therefore cannot be deployed at the spatial andtemporal frequency that is desirable.