SONOMA (CBS 5) -- On a recent day at Sugarloaf Ridge State Park in the Myacamas Mountains, between Sonoma and Napa Valleys, not a soul was to be seen.
But, for Dr. Bernie Krause -- a musician who once performed with the folk group The Weavers -- the peace and quiet is deafening.
"It's all changed now, and it's changing here," he said.
Krause, now a naturalist, is also a bioacoustician. For 44 years, he has recorded sounds found in nature, and in his archive he's collected 4,500 hours of sound. He goes back to the same locations, at the same time of year, and is now noticing a dramatic change.
"The first recordings I did were out in Muir Woods, and it changed my life, " remembered Krause, "It was an epiphany."
Krause played a recording that he made in a meadow at Sugarloaf Ridge in April, 2000. Then he played a recording that he made at the same location but in April 2011.
The difference was striking. The density and diversity of creatures heard in 2000 has dramatically changed. These later sounds, Krause asserts, are the sounds of a damaged habitat.
"I feel a little bit saddened and bereft," said Krause, "because so much of this stuff is gone now."
Dr. Krause said that today, half his archive is from habitats that are either silent or no longer wild. Krause's original recordings may be the only record left of the original diversity and density.
"All I know is what I see and what I record," he said. "I've got the data, I can show the changes, and this is what's happening,"
Krause says you don't have to go very far to see or hear the cause of this changed acoustic environment. Humans are making a lot more noise and, he says, we're silencing nature.
On a graphic display called a spectrogram, Krause showed how wild animals cooperate with each other and share space so they can hear each other, allowing for mating and finding food.
"See how they all stay out of each other's way?" Krause said, as he pointed out distinct voices of different animals and their place on the spectrogram.
He pointed out where the mammals are, the birds, the insects and even the frogs on a recording made in Indonesia.
Krause said too much noise competes with the sounds in the wild and that throws off the animals.
In addition to noise, pollution, mining, global warming even deforestation play a role in throwing the wild animals out of sync with their world.
Krause demonstrated how even a little bit of logging is disruptive. He showed a spectrogram and played a recording of an old growth forest near Truckee that he recorded in 1988. He then recorded the same old growth forest, one year later, after selective logging took place. Once again, the difference was unmistakable: fewer creatures and more silence.
Krause has recorded every year at the same location and said the diversity and density of the animals have never returned to the 1988 levels. He said it has just got worse.
Krause believes we can all benefit if we are quiet and attentive to the natural sounds around us.
"Is this what you want to leave as your legacy for your kids, and your grandchildren in the world that you leave behind, " Krause asked.
For more about Dr. Krause and his work visit www.wildsanctuary.com
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