Ecosystem services of insectivorous bats in intensively managed arable land benefit from adjacent near-natural areas

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.