The sonic landscape of our daily lives is dominated by automobiles, aircraft, HVAC equipment, industrial buildings, and in some cases, drones. Many studies have been completed regarding the effects of noise on people, which include sleep disturbance, increased risk of cardiovascular disease, and more. People are not the only inhabitants of this planet, however…we share this world with an abundance of wildlife. Read on to find out more about the ways that noise affects wildlife ecosystems.
When discussing the impacts of noise on wildlife ecosystems, one of the first species we may consider are bats, which use echolocation to navigate and find prey. Basically, a bat makes a call at a specific frequency for a certain duration and can decipher from the sound that reflects back whether there’s a juicy insect ahead, a brick wall, or a beehive hairdo. Studies have shown that noise pollution from nearby transportation and industrial sites causes a significant reduction in the activity levels of certain bat species compared to locations without noise pollution. The impact of this anthropogenic (human-made) noise is not just about the level, but also the frequency of sound. The narrow bandwidth and long duration of their calls is crucial for navigating their habitat, but some bats appear to modify their echolocation to counteract noise in their environments to improve their ability to detect and capture prey.
Bats are not the only animal species that modify their calls to counter human-made environmental noise. Studies show that frogs, birds, and squirrels have adjusted their calls to a higher pitch to counteract traffic noise. In the case of frogs, this can have adverse effects on the ability of male frogs to attract potential mates, as female frogs tend to prefer lower frequency calls. The higher-pitch calls pierce the elevated background sound near traffic sources, allowing for a larger range of audibility compared to the unmodified calls. This tradeoff between audibility and attractiveness to mates is a fascinating but unintended consequence of noise pollution.
Sometimes, a simple adaptation is not a viable solution to combat the effects of prolonged noise exposure to wildlife. Anthropogenic noise causes all sorts of long-term consequences for animals including decreased levels of reproduction, modified migration patterns, difficulty detecting predators, and general habitat alterations leading to increased stress levels. Accordingly, acoustic solutions for this noise, such as acoustic barriers for highways, limits and regulations on industrial noise, and sound reduction treatments for HVAC equipment are critical. Recently, the prospect of noise and environmental pollution created by new data centers has been a hot button issue across the country. The potential effects of the sound generated by these data centers on both people and wildlife may be significant, and providing appropriate noise criteria and acoustic treatments to offset noise pollution is more important than ever.
The next time you fire up your lawn equipment or emergency generator, think of the bats and frogs!