Noise and Us and Them

Humans are loud.

Cars go by, squealing their brakes, bellowing their horns. Even the docile-looking parked ones can explode into high-pitched whoops, just as you're about to drift off into dreamland. Your neighbors blast their music on and on. The hip-hop was good in the first hour, you think, but now? In the seventh hour? No no no no. Babies cry. You have the misfortune to live next to a construction site, and are woken up at ungodly hours to the awful din of jackhammers. People yell and bump into things and drop heavy objects and even play off key trumpet sometimes. And every once in a while, you think, couldn't everybody just be quiet?!

This could be your neighbor. That would probably be annoying sometimes.
This photo was taken by Böhringer Friedrich

Silence is now a commodity that we're willing to pay for.

Finland started a "Silence, Please" campaign, where they market Finland as a quiet and picturesque country, and that brings many tourists to visit. 

People buy expensive noise-canceling headphones. 

People like me counter noise with other noise. I'm currently listening to a calm playlist put together by the kind people at Focus@Will to counteract the loudest music-players in my dorm: subatomic. 

People spend time and energy trying to find the quietest place near them. 

Some decide to go on months-long hiking trips or meditation retreats, in large part to get away from people, their machines, and their noise.

However, as Finland's "Silence, Please" campaign points out, the number of places where there's no man-made noise is small and dwindling. One of the largest and most ubiquitous perpetrators of anthropogenic noise is roads and the cars on them. One of the best things about roads is that they go almost everywhere. You can get in your car and drive forever and end up anywhere. There is nothing more romantic (according to the movies I've watched) than a road trip heading west into the sunset. One of the worst things about roads is that they go almost everywhere. They spread noise and cars and people to the ends of the Earth, and is that a good thing?

We've seen that busy roads can cut across a species' habitat range, and effectively halve it. This is a phenomenon called habitat fragmentation. Animals that cannot move between fragments must make do with what is available in the place they ended up, even if there are not enough mates or food. But what about the noise?

Highways are noisy, and the noise they create is pretty constant. Here's 11 seconds of that.

A team of scientists in Colorado decided to test how highway noise affects prairie dogs. First they found two sites of prairie dogs that were out of range of road noise. Then, they played recorded audio of a highway for an hour, watched how the prairie dogs acted during that time, waited for 25 minutes, and then recorded for an hour how they acted without the noise. They did this 10 times at each site over the course of three months. They found that the prairie dogs foraged significantly less (cropping or chewing food while standing on all four feet) and were vigilant significantly more (either scanning with head raised and alert on all four legs, or posting with head alert and standing on two legs) during traffic noise exposure. This behavior indicates that the prairie dogs acted as though they were experiencing riskier conditions. Over the course of the experiment, the prairie dogs never habituated to the noise of the highway. This is the first experimental evidence that traffic noise impacts the foraging and vigilance behavior of a free-ranging mammal. These behavior changes lead to lowered body condition, elevated stress levels, reduced fitness and population-level impacts.

Here's a video of prairie dogs reacting to a snake. You get to see a lot of vigilant behavior here, and some foraging.
You also see baby prairie dogs shivering in the cool early morning, which is about the most adorable thing ever.

In the prairie environment, the prairie dogs are a keystone species that are currently living in fragmented habitats. Keystone species are species that have a disproportionately large effect on their environment relative to their abundance. This means that prairie dogs are critically important to the survival of the prairie ecosystem. So, the loss of prairie dogs would lead to an incredible loss of biodiversity.

Over the next 40 years, the amount of road travel is expected to double worldwide, while an estimated 25 million kilometers of road will be constructed. The effects on biodiversity are likely to be substantial, as roads and their side effects greatly affect the fitness levels of important species.

In optimistic times past, pop culture predicted that by the year 2015 we wouldn't need roads. Unfortunately, some things—like hover boards and self-lacing shoes—don't come true. It is now a critical time in our history to ask ourselves how much we are willing to sacrifice in the name of moving forward.

Journal Citation:

Shannon, Graeme, Lisa M. Angeloni, George Wittemyer, Kurt M. Fristrup, and Kevin R. Crooks. 2014. “Road Traffic Noise Modifies Behaviour of a Keystone Species.” Animal Behaviour 94 (August): 135–41. doi:10.1016/j.anbehav.2014.06.004.

Media Credits

Philip Lock. “Highway Noise.” Online video clip. YouTube, 25 November 2014. https://www.youtube.com/watch?v=pGLTa6qeFT8

NatGeoWild. “Prairie Dog Snake Alarm.” Online video clip. YouTube, 25 November 2014. http://www.youtube.com/watch?v=icaGIeOY9gc&t=0m50s

Böhringer Friedrich, Kleinkind mit Trompete. Wikimedia Commons upload, 20 May 2013. Released under the GNU Free Documentation License. http://upload.wikimedia.org/wikipedia/commons/c/c6/Trompeten_B%C3%B6hringer.JPG