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Beauty and the beast: how a bat utilizes forests shaped by outbreaks of an insect pest

Kortmann, M., Hurst, J., Brinkmann, R., Heurich, M., Silveyra González, R., Müller, J., Thorn, S.
Animal conservation 2018 v.21 no.1 pp. 21-30
Chiroptera, acoustics, bark beetles, canopy gaps, foraging, forests, habitat preferences, habitats, lidar, radio telemetry, roosting behavior, salvage logging, snags, surveys, trees
The consequences of different management strategies following natural disturbances are a matter of global concern. In former production forests around the Northern Hemisphere, the abandonment of intervention, such as removal of dead wood, after outbreaks of bark beetles has been increasingly promoted to regain more natural conditions. However, many focal species of conservation, such as the barbastelle bat Barbastella barbastellus, do not primarily depend on dead wood but might respond indirectly to disturbance‐induced changes of forest structural attributes. We investigated the response of B. barbastellus foraging activity and roost selection by combining acoustic surveys, radio telemetry, and airborne light detection and ranging (LiDAR) to characterize B. barbastellus habitat use on different scales. B. barbastellus foraging activity increased with increasing canopy opening. Maternity colonies were recorded exclusively in trees killed by bark beetles. Bats preferred roost trees with a higher volume (m³ ha⁻¹) of live trees in the surrounding, and trees with on average larger diameters than nearby control trees. Our results revealed that outbreaks of bark beetles result in forest structural attributes that are suitable habitat for B. barbastellus. Salvage logging, i.e., the removal of beetle‐affected trees, generally deteriorates the positive effects of bark‐beetle outbreaks on the foraging and roosting habitat of B. barbastellus. We recommend maintaining snags of large diameter if salvage logging is mandatory.