SAN JOSE — Human noise and light are creating fundamental changes in ecological communities — changing the density, diversity and dependencies of bird species that are biological barometers of the natural world.
But peace can be restored to the wilderness by enlisting technologies that create a darker and more silent world, a panel of experts said Monday in San Jose on the final day of the annual meeting of the American Association for the Advancement of Science.
“Noise levels and light levels both can be improved as soon as we decide to throw the switch,” using more electric cars and LED lighting, said Kurt M. Fristrup, of the National Park Service’s Division of Natural Sounds and Night Skies, in Fort Collins, Colorado.
Birds are long-standing indicators of a habitat’s health — the so-called “canaries in the coal mines” that document subtle shifts in the natural world. Noise seems to change where they breed and how they feed; artificial light alters their inner clocks, altering when they wake up and nest.
But chronic stimulation is not just hard on birds, but also humans, Derrick Taff of Pennsylvania State University.
“Natural sounds and dark night skies … are essential for quality human experiences,” helping us restore and recover, he said.
Specifically, the scientists reported that:
It rouses some birds — like blackbirds and robins — two to three hours earlier in the morning than usual. This may offer advantages, such as increasing the birds’ chances of attracting a mate or giving them an earlier start on foraging.
But other birds were indifferent. Late-rising species like finches, he said, “really don’t care.”
Other studies have shown that light at night can affect the composition of invertebrate communities, the foraging behavior of beach mice and shorebirds, the stress response of tuna and the commuting strategies of bats.
Some parts of America remain dark and silent, like Grand Sand Dunes National Park in Colorado, Eastern Oregon or Hawaii’s vast Haleakala Crater, said Fristrup of the National Park Service.
Places like Utah’s Arches National Park, “with a glorious night sky … show how spectacular nighttime skies can be,” he said.
But there are spots on the coast of Southern California, near Long Beach, that are so bright at night that it is possible to read under the dome of urban light from reflective low-lying maritime clouds.
So loud was Muir Woods National Monument that rangers have posted “please be quiet” signs in Cathedral Grove, hoping to stop extraneous audio like ringing cellphones, chatter and iPods. Helicopter chop is the standard soundtrack at Hawaii Volcanoes National Park and the South Rim of the Grand Canyon. Jet planes fly over the most remote peaks of Yosemite.
Constant noise and light affects humans as well.
“Our deep ancestors were anxious,” Fristrup said. “We were not the fastest or best armed, and there were a lot of top predators to pay attention to. When we’re in a cluttered soundscape, we know we’ve lost our surveillance capacity.”
“We may learn to become deaf, or no longer be dark-adapted,” he said.
But a far better strategy, he said, “is to do something about this, and do it quickly.”
“Unlike many other sources of pollution, these are things we can fix. Our technologies can be very effective, if we take advantage of them.”
Contact Lisa M. Krieger at 650-492-4098.
