Movement ecology: the role of environmental cues and sensory mechanisms in bat navigation

蝙蝠是最神秘的动物群体之一。它们是唯一会飞的哺乳动物，在夜间活动，这意味着我们很少看到它们。然而，在整个欧洲，从春天、夏天到秋天的每个晚上，蝙蝠都会从洞穴、树木和建筑物的栖息地飞出来，寻找昆虫的猎物。它们通过发出频率高于人类听觉范围的声纳叫声（“回声定位”）来探测这些声音。它们一晚上可以移动数百公里，但必须在日出前返回栖息地以躲避捕食者。它们如何取得这些非凡的航海壮举仍然是个谜。如果不尽快采取行动，这可能仍然是一个谜，因为尽管有立法保护蝙蝠，但整个欧洲的蝙蝠种类正在减少。蝙蝠提供了一项不常被认识到的重要服务：控制害虫。据估计，仅就节省杀虫剂而言，蝙蝠减少昆虫的经济价值就可能超过数百万英镑。像许多其他物种一样，蝙蝠很容易受到栖息地破坏和其他人为引起的环境变化的影响。具有讽刺意味的是，一项旨在缓解人类对环境变化的措施导致了它们数量的减少。蝙蝠很容易受到“绿色能源”风力涡轮机的碰撞。我们仍然不能完全理解它们为什么这样做，而且令人惊讶的是，考虑到它们能精确地探测到一只小飞虫，它们却不能避开这么大的建筑物。更多地了解它们的运动行为、蝙蝠用于导航的感觉系统和环境线索，以及诱导它们觅食或返回栖息地的环境条件，将有助于减轻这些威胁。这是一个挑战，因为蝙蝠在野外很难研究，所以我们对它们在觅食或迁徙途中的导航行为知之甚少。它们是夜行动物，比鸟类更难观察，因此研究它们导航能力的标准技术就不那么有用了。然而，技术的进步使我们在了解蝙蝠如何在环境中移动方面迈出了第一步，并有可能发现哪些环境线索对它们最重要。这个项目将研究蝙蝠的导航行为，通过操纵它们对环境线索（如太阳和磁场）的感知来了解它们是如何相互作用的，从而告诉动物在需要返回栖息地时该飞哪个方向。通过了解蝙蝠用来导航的感觉系统，我们可以了解哪些环境线索对它们的运动很重要。这些知识可以用来帮助减轻人类对蝙蝠数量的影响。了解它们的行为将使我们能够预测它们移动的时间和地点，这将使风力涡轮机的位置和活动更好，以尽量减少对蝙蝠的干扰。它还将使我们能够根据环境线索的可用性来了解蝙蝠的运动模式，这将有助于预测它们的活动时间模式和栖息地需求。虽然蝙蝠很少被看到，也从未被听到过，但如果我们失去了环境平衡中至关重要的一环，我们肯定会想念它们。因此，了解它们的运动行为是至关重要的，这样我们才能采取行动，避免在夜空中巡逻的蝙蝠数量进一步减少。

Bats are one of the most enigmatic groups of animals. The only flying mammal, they are nocturnal which means we rarely see them. Nevertheless, across Europe, every night through the spring, summer and autumn, bats range out from their roosts in caves, trees and buildings to forage for insect prey. They detect these by producing sonar calls ("echolocation") that are at a frequency high above the human range of hearing. They may range hundreds of kilometers in a night, but must return to their roost before sunrise to avoid predators. How they achieve these remarkable feats of navigation is still a mystery. If action is not taken soon it may remain a mystery as bat species are declining across Europe, despite legislation to protect them. Bats provide a vital service that is not often recognized: that of insect pest control. It has been estimated that the economic value of the reduction of insects by bats may be in excess of millions of pounds in terms of savings in pesticides alone. Like many other species, bats are vulnerable to habitat destruction and other human induced environmental changes. Ironically, one measure introduced to mitigate human change to environmental conditions is causing a reduction in their numbers. Bats are vulnerable to collisions at "green power" wind turbines. Still we do not understand fully why they do this, and it is surprising given the precision with which they can detect a small flying insect that they are unable to avoid such large structures. Understanding more about their movement behaviour and the sensory systems and environmental cues that bats use for navigation, as well as the environmental conditions that induce them to forage or return to their roost will help to mitigate these threats. This is challenging though, as bats have proven hard to study in the wild and so we understand little about their navigation behaviour on foraging or migration trips. Being nocturnal they are far more difficult to observe than birds and so standard techniques for studying their navigational ability are less useful. However advances in technology have allowed us to make the first steps in understanding how bats move about their environment and have the potential to discover which environmental cues are most important to them. This project will study the navigation behaviour of bats by manipulating their perception of environmental cues such as the sun and the magnetic field to understand how they interact to tell the animal which direction to fly when it needs to return to its roost. By understanding the sensory systems that bats use to navigate, we can understand which environmental cues are important for their movement. This knowledge can be used to help mitigate some of the human impacts on bat abundance. Understanding their behaviour will allow us to predict when and where they move, which will enable better placement and activity of wind turbines to minimize disruption to bats. It will also allow us to understand the patterns of movement of bats in terms of the availability of environmental cues, which will aid in predicting their temporal patterns of activity and habitat requirements. While bats are rarely seen and never heard, if we lose this vital cog in the balance of the environment, we would surely miss them. It is thus vital that we understand their movement behaviour in order to allow us to take action to avoid further decline in the number of bats that patrol our night skies.