Blue bird-of-paradise (paradisaea rudolphi) in Papua New Guinea. Photo: 123RF
The world is getting quieter despite all the noise pollution, according to acoustic ecologist Eddie Game.
The Nature Conservancy's Asia Pacific conservation director spends much of his life in rainforests and wilderness areas of the Asia Pacific region, recording the sounds of the wildlife, such as in Papua New Guinea, Indonesia, Myanmar, Australia, and Gabon.
The dawn and dusk choruses just aren't what they used to be, Game tells Lynn Freeman.
“Many people do have this perception that, oh, you know, we've made the world a noisy place full of anthropogenic noises and it's true to an extent,” he says.
“But the overwhelming signature that we see in our recordings that we're making in forests all over the Asia Pacific is that it's getting quieter, especially those dawn and dusk choruses.
“We just see that peak of that noise in the morning just gets a little quieter and a little less complex [as forests degrade]. The great silencing of the dawn - it's probably the saddest thing that we see in this data overall, just how consistent that signature is.”
There’s a saddening trend heard in the region from the library of recordings, he says.
“The whole region is a really busy place, you know, not just the kind of busy populated parts of Asia, but also the islands that exist throughout the Pacific.
“As a location, it's sort of been ground zero for so much of the ecological damage that's happened over the last 30 or 40 years.
“We've seen an enormous loss of species across the Asia Pacific region, and rainforests and certainly healthy batches of forests are getting scarcer and that was one of the driving forces for even starting to listen to forests in this way - was to understand more about how we were damaging them.”
This photograph taken on February 24, 2014 during an aerial survey mission by Greenpeace on Indonesia's Borneo Island shows cleared trees in a forest located in the concession of Karya Makmur Abadi which is being developed for a palm oil plantation. Photo: Bay Ismoyo / aFP
Unlike our ears, the recordings can detect the real “saturation” or complexity in rainforests to understand how healthy they are, Game says.
“One of the eye-opening moments for me is when I started putting headphones on and listening to the rainforest, it's even more noisy than you imagine.
“It's hard for your brain to make sense of the amount of noise and I think it just shows you how much filtering your eyes and your brain do.”
That’s why using computers helps the researchers analyse and interpret the data more consistently, he says.
“In Indonesia, we actually learned something really fascinating from the recordings and we wouldn't have been able to find this out if it wasn't for the sort of way we were recording.
“If you go to some logged forests … overall, the soundscape looks pretty saturated and pretty complex.
“But when you take lots of recordings, we started to notice this trend where forests that had been logged kind of sound the same everywhere, whereas forest that haven't been logged, the proper sort of primary virgin forests, they sound saturated, but also really different everywhere.”
The Nature Conservancy is working closely with forestry companies and the government in Indonesia to discuss options, including looking at ways to build less roads in forests because they can damage the biodiversity.
“I think one of the cool things about sound is you turn up with data that you don't have to just show on a graph, that you can actually have people listen to. And it's a little bit more visceral, it's a better characterisation, I think, of what biodiversity means than most of the plots and charts that we show,” Game says.
His next mission will see him head to the west of the Solomon Islands, where he will analyse the lowland rainforests – something of a rarity in the world because they were often the quickest to disappear due to being on flat land.
