ABSTRACT

Monitoring programmes provide extremely helpful information to understand population dynamics and make effective management decisions, but they are usually constrained by methodological and economical limitations. Advances in bioacoustic technologies offer new opportunities for bat monitoring. In this study, we present a method to monitor small and medium-sized cave-dwelling bat colonies using low-cost AudioMoth passive acoustic recorders. We develop a method to convert bat passes, a measure of acoustic activity, to an estimated number of bats in the roost. To do so, we took audio-visual recordings of five Miniopterus schreibersii colonies emerging from their roosts over 25 nights. We compared the accuracy of the estimates when using site-specific acoustic data against a combined global dataset and examined the influence of the detector position on the estimates. Site-specific acoustic datasets recorded at the cave entrance showed to be adequate to estimate roost bat numbers. In addition, we acoustically monitored one cave during three months of continuous sampling to test our protocol and compared the resulting data with historical datasets of roost occupancy. This method provides a low-cost, non-invasive and simple approach to monitor seasonal and inter-year roost dynamics that can easily be implemented in long-term monitoring programmes and citizen science projects.

摘要

监测计划为了解人口动态和做出有效的管理决策提供了极其有用的信息，但它们通常受到方法和经济上的限制。生物声学技术的进步为蝙蝠监测提供了新的机会。在这项研究中，我们提出了一种使用低成本 AudioMoth 无源录音机监测中小型洞穴栖息蝙蝠群落的方法。我们开发了一种方法来将蝙蝠传球（一种声学活动的度量）转换为栖息地中蝙蝠的估计数量。为此，我们拍摄了五只Miniopterus schreibersii的视听录音在 25 个晚上从它们的栖息地出现的殖民地。我们比较了使用特定地点声学数据与综合全球数据集时估计的准确性，并检查了探测器位置对估计的影响。在洞穴入口处记录的特定地点声学数据集足以估计栖息蝙蝠的数量。此外，我们在三个月的连续采样期间对一个洞穴进行了声学监测，以测试我们的协议，并将所得数据与栖息地占用的历史数据集进行比较。这种方法提供了一种低成本、非侵入性和简单的方法来监测季节性和跨年栖息地动态，可以轻松地在长期监测计划和公民科学项目中实施。