E-BIKE HIGH FREQUENCY NOISE AND POTENTIAL IMPACTS TO ROOSTING BATS
|Dave S Johnston; H. T. Harvey & Associates; email@example.com;|
Bats are acutely sensitive to changes in their sound environment and can react to relatively quiet noise if it is foreign to them and stimulates a stress response. Additionally, the frequency of the noise is also important because individual species of bats have different sensitivities to various noise frequencies. To determine if e-bikes produce high frequency sounds that potentially disturb and impact bats, we recorded three e-bike models and two conventional bike models with high frequency and low frequency microphones spaced at 10 ft., 20 ft., 40 ft., and 80 ft. away from passing e-bikes/conventional bikes in each of four modes (pedal slowly, pedal fast, coasting, and braking). Based on the modelled attenuation of noise to ambient noise levels for different phonic groups of bats, we recommend buffer distances between e-bike traffic to day roosting bats of 100 ft. for 20 kHz bats, 107 ft. for 30 kHz bats, 231 ft. for 40 kHz bats and 134 ft. for 50 kHz bats.