Bats increased foraging activity at experimental prey patches near hibernacula

1. Emerging infectious diseases in wildlife can threaten vulnerable host
populations. Actions targeting habitat improvements to aid population
resilience and recovery may be beneficial long-term strategies, yet
testing the efficacy of such strategies before major conservation
investments are made can be challenging. 2. The disease White-nose
Syndrome (WNS) has caused severe declines in several species of North
American hibernating bats. We tested a novel conservation approach
targeted at improving foraging conditions near bat hibernacula by
experimentally manipulating insect density in the pre-hibernation
fattening period and spring emergence recovery period. We measured
foraging (feeding buzzes) and echolocation activity of little brown bats
(Myotis lucifugus) at ultraviolet (UV) light lures to determine behavioral
response to augmented foraging conditions and characterized insect
availability at UV light lures. 3. In the fall, bat foraging activity was
3 times greater (95% CI: 1.5–5.8; P = 0.002) when UV lights were on, but
there was no statistical support for differences in echolocation activity
response when our experimental design alternated between nights with
lights on and off. In the spring, we allowed UV light lures to run
consistently each night and compared with a control location in similar
habitat. Bat foraging activity was 8.5 times greater (95% CI: 4.5–16.0; P
< 0.0001) and echolocation activity was 4.4 times higher (95% CI:
3.0–6.5; P < 0.0001) at UV light lures in the spring experiment. In
both the fall and spring, UV light lures resulted in concentrated insect
availability, attracting primarily moths (Order: Lepidoptera). In both
seasons, nightly temperature had a strong influence on bat foraging,
echolocation, and insect activity. 4. We show that a bat species
threatened by WNS used enhanced foraging habitats near hibernacula during
the critical pre- and post-hibernation phases of their annual cycle. While
light lures are unlikely to be a long-term management strategy, our
experiment provides initial evidence that bats behaviorally respond with
increased foraging activity in areas with augmented insect prey
availability. Our experimental results support developing management
strategies focused on habitat protection, including restoration and
enhancement of foraging habitats, in the immediate vicinity of bat
hibernacula.