Bat activity 22 years after first-round intensive logging of alternate coupes near Eden, New South Wales

Summary

Bat activity was recorded in eight paired coupes of unlogged forest and 22-year-old regrowth forest, near Eden in southern New South Wales. Regrowth coupes had been clearfelled in 1976, with no retention of habitat trees or riparian buffers on minor forest streams. Ultrasonic detectors (Anabat) positioned off-flyways recorded an average of 87 passes in the first two hours after dark in unlogged coupes compared to 36 passes in regrowth coupes. This difference was probably due to considerable ‘clutter’ in the regrowth compared to the open forest structure of unlogged coupes. The overall rate of feeding (feeding buzzes/total passes) was very low in this study (3% in unlogged, 0.9% in logged). Low activity in regrowth was consistent for less maneuverable bat species, although those with a large body size were too rare to be tested. Despite low activity in regrowth, trapping rate on tracks was high, although 20% less than in unlogged coupes. Across the logged/unlogged mosaic, 11 bats were caught per harp-trap night. Roads and tracks provide linear edge habitat that may be an important ameliorative measure allowing a range of bat species to exploit habitat otherwise too cluttered for foraging. A significant bias towards capturing more females in unlogged coupes suggests maternity roosts were located in such areas and emphasizes the importance of retaining roost trees (now a standard practice in buffer zones and as habitat trees within logged areas) for bats.

Keywords:

• wildlife
• habitat
• surveys
• silvicultural systems
• logging
• bats