Marit Kelling, Carolin Scholz, Manuel Roeleke, Torsten Blohm, Jan Pufelski, Ran Nathan, Sivan Toledo, Florian Jeltsch, Christian C. Voigt

Ecosystem services provided by insectivorous bats are an important yet underappreciated economic benefit of biodiversity. To investigate what is needed to maintain these services, we asked whether bat-mediated ecosystem services depend on near-natural areas adjacent to farmland. We used high-throughput tracking and genetic sequencing to determine the habitat use and diet of 128 common noctule bats (Nyctalus noctula). Common noctule bats spent an average of 55% of their foraging time over arable land, although arable land made up more than 95% of the area within their activity range, indicating avoidance. In contrast, bats foraged 14% of the time over water and wetlands, which constituted only 0.5% of the area, indicating a strong preference. Consequently, the overall diet consisted mainly of insects with aquatic larval stages. Of all insects consumed, 23% were pests, highlighting the ecological importance of noctule bats in both near-natural and human-altered ecosystems. Our data suggest that the ecosystem services provided by bats on farmland may depend strongly on adjacent near-natural areas where they can find sufficient insects to meet their energy demands. These findings highlight the need to maintain a high degree of habitat heterogeneity for the conservation of bat species and their contribution to sustainable agriculture.