NEW RESEARCH has assessed bat populations across broadleaved woodlands managed in different ways, highlighting the management practices that are good for these popular wee native mammals.

Changes in woodland management have been linked to declines in birds and other wildlife but little has been known about the impacts of such changes on our bat populations. All 17 bat species found breeding in the UK use woodlands, and many are reliant on semi-natural broadleaved tree environments.

just published in the journal Forest Ecology and Management, the research by lead author Danny Alder used special acoustic recorders to capture the echolocation and other calls made by bats using the study sites. Through this he was able to identify the species involved and could then measure their activity across the different woodland habitats.

He collected data on the structural features of the woodlands, like the degree of canopy cover, tree size, density of the understorey and the amount of standing dead wood, all of which can influence a woodland’s suitability for bats.

Eleven bat species were identified, including the rare Barbastelle, and there were clear differences between the different woodland management types in terms of both occupancy by bats and their activity. ‘Irregular High Forest’, a woodland type where the forest ecosystem is maintained intact by selective felling and characterised by its mixed-sized trees and complex structure, had the richest bat community and highest occupancy rates for most bat species.

The study demonstrated how features associated with Irregular High Forest stands, including deadwood, understorey structure, open canopy areas and larger tree size, seemed to benefit multiple bat species across different foraging guilds. Barbastelle – a low-level forager – was significantly associated with areas of more open canopy across all of the different stand management types, though with highest occupancy in the Irregular High Forest stands. The importance of this, and the other features highlighted, should be taken into account when considering how best to manage woodland for bats.

Mr Alder commented: "Through our work we have identified important associations between bat species and woodland structure, demonstrating how the management practices associated with Irregular High Forest promote many of the structural features which positively influence bats. Importantly, our study also shows that an emphasis on non-intervention as the appropriate woodland management treatment for bat conservation may be misleading without an understanding of the structural characteristics present."