Testing the effectiveness of two methods of summer bat fauna inventory

Effective techniques of fauna inventory and biodiversity monitoring are essential for obtaining reliable data on species composition, population structure, and habitat use. Bats remain one of the least studied groups of mammals, yet they are important
indicators of natural habitat condition. We present a comparison of the results of two survey methods, mist-netting and acoustic recordings, conducted at the same locations to assess summer bat assemblages in the National Nature Park “Homilsha Forest” (Kharkiv Region, Ukraine). Mist-netting yielded 440 individuals of 10 bat species, while acoustic recordings allowed the detection of 8 species, with a total of 3,468 echolocation sequences treated as individual records. Two species (Myotis brandtii and Pipistrellus kuhlii) were detected exclusively through mist-netting, whereas all other species were detected by both survey methods. The Jaccard index ranged from 0.70 to 0.80, indicating partial overlap of the two survey methods in terms of species detection. Species relative abundance differed significantly between the two methods (Сhi-square test, p < 0.001). Mist-netting and acoustic recordings yielded different estimates of relative abundance for several species, suggesting method-specific biases in a bat species abundance assessment. The survey method also had a significant effect on species richness and relative abundance (two-way ANOVA, p < 0.05). In summary, we recommend a mist-netting survey as the best method for
species identification (and population structure) and acoustic recording as a monitoring tool for summer bat assemblages.