Contrasting effects of mixed farming on bats are mediated by local and landscape features and differ between seasons

Abstract

Homogenisation of agricultural landscapes, driven by intensive farming, is one of the key drivers of biodiversity decline in Europe. Whilst government schemes to address this have benefitted some invertebrate species, they have been less successful for bats, which require a landscape-scale approach due to their high mobility. ‘Mixed farming’, where livestock are integrated into arable crop rotation, has been proposed as a landscape-scale approach to counteract biodiversity loss and could benefit bats via increased diversity of foraging habitats, both spatially and temporally (e.g. in the autumn when arable fields are ploughed, pasture may provide an alternative source of insect prey). We used structural equation models to investigated direct and indirect effects of mixed farming on bat activity and how these effects change between seasons. Bat activity was quantified on 26 farms in Scotland (UK) in summer 2022 and in autumn 2023 and 2024 using acoustic methods. On mixed farms, bats avoided arable fields in favour of grassland or woodland. Woodland edge density – which was higher on mixed than on arable farms – was positively associated with the occurrence of Myotis species. The activity of Pipistrellus and Myotis species was also positively associated with the height of treelines and hedgerows (which were marginally shorter on mixed farms than on arable farms). Bat responses differed between seasons, with habitat diversity becoming more important for Pipistrellus pipistrellus in the autumn, highlighting the importance of monitoring bats across the seasons to identify factors influencing bat activity.