UK Centre for Ecology & Hydrology, Wallingford, Oxfordshire, United Kingdom.
Department of Biology, University of Oxford, Oxford, United Kingdom.
PLoS One. 2022 Nov 11;17(11):e0277545. doi: 10.1371/journal.pone.0277545. eCollection 2022.
Passive rewilding is a potential tool for expanding woodland cover and restoring biodiversity by abandoning land management and allowing natural vegetation succession to occur. Land can be abandoned to passive rewilding deliberately or due to socio-economic change. Despite abandonment being a major driver of land use change, few have studied the long-term outcomes for vegetation and biodiversity in Western Europe. Studies are also biased towards sites that are close to seed sources and favourable to woodland colonisation. In this case-study, we reconstruct a time series of passive rewilding over 33 years on 25 ha of former farmland that had been subject to soil tipping, far from woodland seed sources. Natural colonisation by shrubs and trees was surveyed at three points during the time series, using field mapping and lidar. Breeding birds were surveyed at three time points, and compared with surveys from nearby farmland. Results showed that natural colonisation of woody vegetation was slow, with open grassland dominating the old fields for two decades, and small wetlands developing spontaneously. After 33 years, thorny shrub thickets covered 53% of the site and former hedgerows became subsumed or degraded, but trees remained scarce. However, the resulting habitat mosaic of shrubland, grassland and wetland supported a locally distinctive bird community. Farmland bird species declined as passive rewilding progressed, but this was countered by relatively more wetland birds and an increase in woodland birds, particularly songbirds, compared to nearby farmland. Alongside biodiversity benefits, shrubland establishment by passive rewilding could potentially provide ecosystem services via abundant blossom resources for pollinators, and recreation and berry-gathering opportunities for people. Although closed-canopy woodland remained a distant prospect even after 33 years, the habitat mosaic arising from passive rewilding could be considered a valuable outcome, which could contribute to nature recovery and provision of ecosystem services.
被动再野化是通过放弃土地管理并允许自然植被演替来扩大林地覆盖和恢复生物多样性的潜在工具。土地可以被故意放弃用于被动再野化，也可以因社会经济变化而被放弃。尽管放弃是土地利用变化的主要驱动因素之一，但很少有人研究西欧植被和生物多样性的长期结果。这些研究也偏向于靠近种子源且有利于林地殖民化的地点。在本案例研究中，我们在远离林地种子源的 25 公顷曾经进行过土壤倾倒的农田上，重建了长达 33 年的被动再野化时间序列。使用实地测绘和激光雷达，在时间序列的三个时间点调查了灌木丛和树木的自然殖民情况。在三个时间点调查了繁殖鸟类，并与附近农田的调查进行了比较。结果表明，木本植被的自然殖民化速度缓慢，开阔的草地在过去二十年中主导了旧农田，小湿地也自发形成。33 年后，多刺灌丛覆盖了该场地的 53%，而先前的树篱则被吞并或退化，但树木仍然稀少。然而，由此产生的灌丛、草地和湿地的栖息地镶嵌体支持了一个具有本地特色的鸟类群落。随着被动再野化的进行，农田鸟类的数量减少，但湿地鸟类的数量相对增加，林地鸟类，特别是鸣禽的数量也有所增加，与附近的农田相比有所增加。除了生物多样性的好处外，被动再野化灌木林的建立还可以通过为传粉者提供丰富的花蜜资源，以及为人们提供娱乐和采摘浆果的机会，来提供生态系统服务。尽管即使经过 33 年，仍然没有形成封闭的树冠林，但被动再野化产生的栖息地镶嵌体可以被认为是一个有价值的结果，可以为自然恢复和生态系统服务提供贡献。
