Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia.
Department of Agriculture and Fisheries, Queensland Centre for Emerging Infectious Diseases, Brisbane, QLD, 4001, Australia.
BMC Biol. 2020 Aug 21;18(1):101. doi: 10.1186/s12915-020-00829-w.
Effective conservation management of highly mobile species depends upon detailed knowledge of movements of individuals across their range; yet, data are rarely available at appropriate spatiotemporal scales. Flying-foxes (Pteropus spp.) are large bats that forage by night on floral resources and rest by day in arboreal roosts that may contain colonies of many thousands of individuals. They are the largest mammals capable of powered flight, and are highly mobile, which makes them key seed and pollen dispersers in forest ecosystems. However, their mobility also facilitates transmission of zoonotic diseases and brings them in conflict with humans, and so they require a precarious balancing of conservation and management concerns throughout their Old World range. Here, we analyze the Australia-wide movements of 201 satellite-tracked individuals, providing unprecedented detail on the inter-roost movements of three flying-fox species: Pteropus alecto, P. poliocephalus, and P. scapulatus across jurisdictions over up to 5 years.
Individuals were estimated to travel long distances annually among a network of 755 roosts (P. alecto, 1427-1887 km; P. poliocephalus, 2268-2564 km; and P. scapulatus, 3782-6073 km), but with little uniformity among their directions of travel. This indicates that flying-fox populations are composed of extremely mobile individuals that move nomadically and at species-specific rates. Individuals of all three species exhibited very low fidelity to roosts locally, resulting in very high estimated daily colony turnover rates (P. alecto, 11.9 ± 1.3%; P. poliocephalus, 17.5 ± 1.3%; and P. scapulatus, 36.4 ± 6.5%). This indicates that flying-fox roosts form nodes in a vast continental network of highly dynamic "staging posts" through which extremely mobile individuals travel far and wide across their species ranges.
The extreme inter-roost mobility reported here demonstrates the extent of the ecological linkages that nomadic flying-foxes provide across Australia's contemporary fragmented landscape, with profound implications for the ecosystem services and zoonotic dynamics of flying-fox populations. In addition, the extreme mobility means that impacts from local management actions can readily reverberate across jurisdictions throughout the species ranges; therefore, local management actions need to be assessed with reference to actions elsewhere and hence require national coordination. These findings underscore the need for sound understanding of animal movement dynamics to support evidence-based, transboundary conservation and management policy, tailored to the unique movement ecologies of species.
高度移动物种的有效保护管理取决于对个体在其范围内的移动情况的详细了解；然而，很少有数据能够以适当的时空尺度获得。狐蝠（Pteropus spp.）是一种大型蝙蝠，它们在夜间觅食，白天则在可能容纳数千只个体的树上栖息。它们是唯一能够进行动力飞行的最大哺乳动物，具有高度的流动性，这使它们成为森林生态系统中关键的种子和花粉传播者。然而，它们的流动性也促进了人畜共患病的传播，并使它们与人类发生冲突，因此，在整个旧大陆范围内，它们需要在保护和管理需求之间进行微妙的平衡。在这里，我们分析了 201 只卫星追踪个体在澳大利亚范围内的运动情况，提供了关于三种狐蝠物种（Pteropus alecto、P. poliocephalus 和 P. scapulatus）在长达 5 年的时间里在司法管辖区之间的栖息点间运动的前所未有的详细信息。
个体每年在 755 个栖息点组成的网络中估计会进行长途迁徙（P. alecto，1427-1887 公里；P. poliocephalus，2268-2564 公里；P. scapulatus，3782-6073 公里），但它们的迁徙方向几乎没有一致性。这表明狐蝠种群由极其活跃的个体组成，它们以游牧的方式以特定的速度移动。三种物种的个体对当地栖息地的忠诚度都非常低，导致极高的估计每日种群周转率（P. alecto，11.9±1.3%；P. poliocephalus，17.5±1.3%；P. scapulatus，36.4±6.5%）。这表明狐蝠栖息地形成了一个广阔的大陆网络中的节点，这些节点是高度动态的“中途停留点”，极其活跃的个体在其物种范围内通过这些节点进行远距离的移动。
这里报告的栖息地间极高的移动性表明，游牧狐蝠在澳大利亚当代破碎景观中提供的生态联系程度，这对狐蝠种群的生态系统服务和人畜共患病动态产生了深远的影响。此外，这种极高的流动性意味着当地管理行动的影响很容易在整个物种范围内的司法管辖区内产生连锁反应；因此，需要参考其他地方的行动来评估当地的管理行动，因此需要国家协调。这些发现强调了需要对动物运动动态有良好的了解，以支持基于证据的跨境保护和管理政策，这些政策需要针对物种独特的运动生态进行调整。
