It’s spring so the garden is full with a cacophony of bird song. Sparrows, blackbirds, starlings, doves, tui, kereru, rosellas, ducks and ducklings, turkeys and pukeko are all making a racket around my place. Nature is noisy. But there’s a bigger problem with noise in the environment, and that’s anthropogenic (human-generated) sound that’s having major impacts on the world around us. Noise in the urban environment can be an economic and political phenomenon. Loud noises can be expressions of power – dominating the soundscape. Think of Harley Davidson bikes or loud music. Researchers find that different towns and cities have different soundscapes depending on the different activities that occur there. Industrial areas and places close to motorways and other utilities, differ greatly from wealthier, residential leafy suburbs.
Increased noise levels can lead to cardiovascular impacts on humans, increased coronary disease, stress, anxiety, insomnia and mental illness. But the adverse effects of human- generated noise go further than just urban areas and impact life of all types. Studies show animals that are affected by human noise include bats, owls, frogs, prairie dogs, various birds, squid, cephalopods, whales, dolphins, fish larva and even crabs.
Studies in America have shown that even in wilderness areas “new” noise was up to 10 times the original background noise. In some places, noise “overrides” natural areas.
There are now few naturally quiet areas on the land or in the sea.
Increasing noise can cause species displacement, changed predator/prey detection and avoidance, interference with reproduction and migration, even complete hearing loss.
Because the world is noisier by day, birds are adapting by singing at night.
Meanwhile, animals generally are having to raise the volume of their vocalisations. As individual animals vocalise more loudly to be heard over human noise, the whole animal community ends up being louder. In the US, noise is negatively affecting whole ecosystems. Scrub jays usually bury pine seeds, and in doing so perpetuate new forest growth. But because they are moving away from noisy sites, they are not there to bury the seeds and regeneration for future forests is thwarted.
In New Zealand, there are limited studies on the impact of noise on wildlife. According to a Department of Conservation literature review, it’s usually short term and ad hoc for a specific purpose. Nevertheless, studies that have been done do show effects, especially of sudden sounds, on wetland wildlife.
by Christine Rose