Sown wildflower fields create temporary foraging habitats for bats in agricultural landscapes

Abstract

While land-use change threatens insectivorous bats, there is a lack in conservation measures targeting bats in temperate agro-ecosystems. Further, there is no consensus on shared benefits of existing conservation measures either. To unravel the causal factors behind the failure and success of conservation measures, we studied whether sown wildflower fields create sufficient ecological contrast and adequate foraging habitats for insectivorous bats and if potential benefits depend on landscape context.From June to September 2020, we simultaneously monitored insects and bats on paired wildflower and crop fields in landscapes with increasing complexity, here shares of semi-natural habitats such as hedgerows. We compared insect and specifically moth abundance as well as overall bat and foraging activity between wildflower and crop fields and studied effects of prey abundance on bat activity.During summer, insect and moth abundances were two- to fourfold higher on wildflower than crop fields. On wildflower fields, insect abundances increased with wildflower cover, while moth abundances increased with shares of semi-natural habitats. Bat activity on wildflower compared to crop fields was higher during the beginning and lower towards the end of summer. Both bat and foraging activity increased with insect abundance and decreased with patch size of wildflower fields.Wildflower fields seem to be a promising tool to provide adequate foraging habitats for insectivorous bats in agro-ecosystems but sufficient prey availability may be key, particularly during times of high food demand. Moreover, it seems vital to target complex landscapes and foster the retention and reintroduction of hedgerows in agro-ecosystems.