The effect of artificial light on the activity of ʻōpeʻapeʻa, the Hawaiian hoary bat
Team ‘Ōpeʻapeʻa, Kristin Jonasson, Brad Yuen, and Dave Johnston
Artificial lighting attracts insects eaten by the ʻōpeʻapeʻa, yet the effect of artificial lighting on the ʻōpeʻapeʻa is poorly understood. We measured bat activity at artificial lights and unlit areas and hypothesized that bat activity would be higher in lighted areas.
We set out SM2BAT detectors (Wildlife Acoustics, Maynard, MA) on Kamehameha Schools Maui campus to record acoustic bat activity. We put bat detectors at 7 dark locations (away from lights) and 7 lighted locations (near lights). Bat detectors recorded for two nights at each location.
Methods
We set out SM2BAT detectors (Wildlife Acoustics, Maynard, MA) on Kamehameha Schools Maui campus to record acoustic bat activity. We put bat detectors at 7 dark locations (away from lights) and 7 lighted locations (near lights). Bat detectors recorded for two nights at each location.
In total, we recorded 4641 files containing bat calls, 1250 at dark locations (mean = 89 files per night) and 3391 at lighted locations (mean = 242 files per night).
Overall, bat activity was higher at lighted locations than at dark locations.
Results
In total, we recorded 4641 files containing bat calls, 1250 at dark locations (mean = 89 files per night) and 3391 at lighted locations (mean = 242 files per night).
Overall, bat activity was higher at lighted locations than at dark locations.
General bat activity was higher at lighted locations than at dark locations, but our sample size was small and there are outliers in the results. Bat activity was also high at both lighted and dark locations on May 7th and 8th and bat activity was higher in dark locations on May 23rd and 24th. Additionally, there were many lights on campus for bats to choose from and even dark locations were slightly illuminated. Our study highlights the need for further research with better controls and a larger sample size.
