Data for: Large-scale long-term passive-acoustic monitoring reveals spatiotemporal activity patterns of boreal bats

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.