Author(s): Takahiro Sato; Yoichi Kawaguchi; Shin Nakanishi; Takumi Akasaka

Linked Author(s): Takahiro Sato

Keywords: Coustic monitoring; Echolocation; Bat activity; Reservoir management; Chiropter

Abstract: Dams are an essential infrastructure for modern human society. However, habitat alterations caused by dam constructions have negatively affected terrestrial vertebrates including highly mobile mammals such as bats. Because of their high diversity and abundance, bats are important terrestrial consumers where they fulfill a crucial role for aquatic-terrestrial nutrient linkage. Bats can be a suitable indicator to evaluate the impacts of dams on ecological functions, but little is known about patterns of bat activity over aquatic habitats affected by dams, particularly in east Asia. In this study, we aimed to compare foraging activity of bats by acoustic monitoring in different areas of riparian habitats altered by dams in Naka River flowing through the southern Tokushima, Japan. Foraging activity was recorded at three dam reservoirs and the downstream reach of each dam during the autumn 2021. Total two species of Rhinolophus and three bat groups (Myotis spp., Miniopterus/Pipistrellus and low-frequency call bats) were detected by the acoustic identification. We found that foraging activity of Myotis spp. and of Miniopterus/Pipistrellus group was highest in the reservoir of Kawaguchi Dam, which shows little fluctuation of the water level. Myotis spp. also showed consistently higher foraging activity at reservoirs than that of downstream reaches. These results suggest that dam reservoirs could be an important foraging habitat, particularly for bats preferring the smooth water surface to hunt emerging aquatic insects. Ourfindings highlighted that understanding bat responses to anthropogenically controlled water bodies could contribute to the future dam water management and conservation of bat assemblages.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p1300-cd

Year: 2023