THE DISTRIBUTION OF THE NORTHERN BAT EPTESICUS NILSSONII (KEYSERLING & BLASIUS, 1839) IN LATVIA ASSESSED BY PASSIVE ACOUSTIC SURVEY

Abstract

The latest study about the distribution of bat species in Latvia was published in 1998. The rapid development of automatic ultrasound detectors has enabled researchers to conduct extensive bat acoustic monitoring. Thus, the knowledge on the distribution of many bat species in Latvia has increased in the last 20 years. The aim of this study was to examine the differences in the activity of the northern bat Eptesicus nilssonii (Keyserling & Blasius, 1839) across four geographical regions of Latvia using data provided by three-year bat acoustic monitoring program. We analyzed bat calls expressed as bat activity from 60 randomly selected LKS-92 25x25 km squares with a total of 360 observation stations. We found that E. nilssonii is less common in the southeastern part of Latvia and more common in the south-west and northwest parts of Latvia. Thus, though E. nilssonii is widespread, the distribution of across Latvia is uneven. However, further studies are needed to examine the possible drivers of differences in the distribution of this species.