The distribution ranges and spatio-temporal patterns in the occurrence and activity of boreal bats are yet largely unknown due to their cryptic lifestyle and lack of suitable and efficient study methods. We approached the issue by establishing a permanent passive-acoustic sampling setup spanning the area of Finland to gain an understanding on how latitude affects bat species composition and activity patterns in northern Europe. The recorded bat calls were semi-automatically identified for three target taxa; Myotis spp., Eptesicus nilssonii or Pipistrellus nathusii and the seasonal activity patterns were modeled for each taxa across the seven sampling years (2015–2021). We found an increase in activity since 2015 for E. nilssonii and Myotis spp. For E. nilssonii and Myotis spp. we found significant latitude -dependent seasonal activity patterns, where seasonal variation in patterns appeared stronger in the north. Over the years, activity of P. nathusii increased during activity peak in June and late season but decreased in mid season. We found the passive-acoustic monitoring network to be an effective and cost-efficient method for gathering bat activity data to analyze spatio-temporal patterns. Long-term data on the composition and dynamics of bat communities facilitates better estimates of abundances and population trend directions for conservation purposes and predicting the effects of climate change.

中文翻译：

---

大规模长期被动声学监测揭示北方蝙蝠的时空活动模式

由于其神秘的生活方式和缺乏合适和有效的研究方法，北方蝙蝠的出现和活动的分布范围和时空模式在很大程度上仍然未知。我们通过建立一个跨越芬兰地区的永久性被动声学采样装置来解决这个问题，以了解纬度如何影响北欧的蝙蝠物种组成和活动模式。记录的蝙蝠叫声是针对三个目标类群半自动识别的；在七个采样年（2015-2021 年）中，为每个分类群模拟了鼠耳蝠、Eptesicus nilssonii或Pipistrellus nathusii以及季节性活动模式。我们发现自 2015 年以来E. nilssonii和鼠耳草属 对于E. nilssonii和Myotis spp。我们发现了显着的依赖于纬度的季节性活动模式，其中模式的季节性变化在北部显得更强。多年来，P. nathusii的活动在 6 月和晚季的活动高峰期间增加，但在季中减少。我们发现被动声学监测网络是收集蝙蝠活动数据以分析时空模式的有效且经济高效的方法。有关蝙蝠群落组成和动态的长期数据有助于更好地估计数量和种群趋势方向，以实现保护目的和预测气候变化的影响。