Noah Baker
This is a podcast extra from Nature. It’s a little bit different from what you might expect from us. And for this one, I’d recommend putting on a good pair of headphones, lying back and immersing yourself in what’s to come – a story of sound, science, technology and the natural world.
Simon Butler
All of our senses allow us to engage with nature, but sound is a particularly important component of that. As we spend time outside, it’s often birdsong and insect calls that are the soundtrack to that experience, and that is what underpins everything. And although we might not necessarily be immediately aware of it, it’s there in the background the whole time, providing that soundtrack.
Simon Butler
I’m Simon Butler and I’m a conservation ecologist with a particular interest in acoustic ecology and the sounds of nature.
Simon Butler
When you think about the public awareness campaigns for various conservation actions, they’re often very visual – the lone orangutan in a tree surrounded by farmland, images of horns being cut off rhinos or of turtles eating plastic bags. All of those are quite visual stimuli to raise awareness of conservation issues. But I think the soundscapes idea is underused at the moment, and the opportunities to use soundscapes as a real focus for raising awareness of the impacts of humans on the environment and on biodiversity, I think there’s a lot of potential in that. We know that sounds offer that sense of place. We know that sounds are frequently used to take us to a location or take us to a time or a season, and if we start to think about how we’re impacting on those sounds, I think that’s a really strong opportunity to motivate our thinking about conservation actions.
Simon Butler
So, not only are soundscapes really important for our own personal mental health and wellbeing, but we’re also increasingly growing to recognise that they can be used to measure the health of an ecosystem through their acoustic properties.
Simon Butler
And so, my work focuses on trying to record, document and even recreate natural soundscapes as a way of better understanding our changing world.
Simon Butler
My early morning starts with a 6:30 alarm, and it’s up and out straight away with the dog. She’s always desperate to get outside. We live out in rural Norfolk, and walking the country lanes, listening to the world wake up is really valuable and really enjoyable. So, this time of year, it’s just getting light as we go out. We often see deer in the fields, rabbits running across the roads, and the birds are just starting to sing. Robins and blackbirds are just coming to life. But as we move through the winter and then into the spring, it’s the arrival of the first migrants and the sounds of the swallows starting to arrive that then can really bring added enjoyment and pleasure to those early morning walks.
Simon Butler
In temperate climates in particular, birdsong is the main contributor to our natural soundscapes, and most often we hear rather than see birds. So, that’s the key route by which we engage with nature and draw benefits from that. Since the 1950s, the American bird population has declined by 3 billion birds. In Europe, over the last 40 years, we’ve seen a loss of 600 million birds occurring from the aviary fauna, and all of those individuals, which once would have contributed to the soundscape, are now gone.
Simon Butler
We’re really interested in trying to understand the impacts of ongoing biodiversity loss for soundscape quality, but unfortunately we don’t have historical recordings of soundscapes to be able to understand what places used to sound like. Fortunately, what we do have is long-term bird monitoring data, and we wanted to explore how these data could be used to reconstruct the soundscapes of our past.
Simon Butler
So, across Europe and North America, there are some fantastic long-term bird monitoring schemes, where citizen scientists will go out and count the number of species and the number of individuals of those species at that site, in that year. We can use those underlying bird monitoring data to start to reconstruct soundscapes of different sites and different years, going back several decades for 200-odd thousand sites across North America and Europe. We can reconstruct what it might have sounded like to be standing next to that citizen scientist as they were collecting those data.
Simon Butler
We can’t directly interpret the count data to understand how soundscapes might have changed because the loss or the gain of an individual species will have a different impact on the composite soundscape according to what else is there at that time. So, we might lose a warbler species, and the impact of that might change according to what other warbler species are there. And similarly, if we lose a warbler compared to a corvid, although we might only be losing one species, the impact of that will be very different because of the changes and the differences in their song structure and their call structure.
Simon Butler
And so, really, the only way to properly understand changes in the quality of soundscapes is to hear them, and that means reconstructing them.
Simon Butler
We reconstructed our soundscapes by combining the citizen science bird monitoring data with recordings of individual bird species. So, if we take an individual site in an individual year, the monitoring data would give us a list of species and a count of the number of individuals of each of those species. And what we would do is then combine the same number of recordings of the bird species for the individuals that were counted. So, for example, if 5 skylarks were counted at a site, we would introduce 5 clips of skylark singing into our constructed soundscape. And then we would layer up individuals and layer up species to build a composite soundscape for that site in that year that represents the species’ community that was observed at that site.
Simon Butler
Our results show that there’s been a chronic and pervasive decline in acoustic quality across North America and Europe over the last 25 years, so our natural soundscapes have become less diverse and become less intense.
Simon Butler
So, modern soundscapes are quieter. There’s fewer individuals contributing to those soundscapes. And they’re also homogenous – there’s fewer species contributing to that – and so the variation is lower.
Simon Butler
Perhaps that’s not that surprising given the large-scale declines in biodiversity loss that we know are occurring, but actually, to be able to hear it and to be able to realise the tangible impact in that I think is a really powerful demonstration of the costs that we are incurring through biodiversity loss.
Simon Butler
When you have these slow but continuous declines in anything in soundscape quality, it’s difficult to detect that they’re occurring because they’re just benign and chronically changing. And going back and listening to a stark point, a single point back 25 years ago, you realise how much these soundscapes have changed and how much better, how much richer, how much more diverse they used to sound.
Simon Butler
And it’s very sad to hear the impacts of biodiversity loss on how we can experience nature and how we can spend time in nature, and what the benefits that we might gain from that, how much they’ve declined over that time period.
Simon Butler
In our study, we only focused on birds as contributors to natural soundscapes, but the reality is that many other species that might contribute to our natural soundscapes are also declining. So, we’ve seen losses in insects, we’ve seen losses in amphibians, and all of those would have been contributing to soundscapes, and the deterioration is therefore likely to be even greater than we report here. And on top of that, we’ve got increases in noise pollution from human activities.
Simon Butler
As we spend more time indoors, sat at our computers, on our mobile phones, whatever it might be, we’re suffering from an extinction of experience, which means the quantity of the time we spend in nature is reducing. And then when we do go outside, the quality of the experience of nature that we do have is reducing as well because not only have we got biodiversity loss occurring but we’ve also got these increases in noise pollution and other human noises that are impacting on our surrounding soundscapes.
Simon Butler
So, we’ve got both this decline in biodiversity reducing the number of players in our natural orchestra, but we’ve also got this increase of noise pollution as well, and both of those are combining to reduce the overall quality.
Simon Butler
Lots of research has explored the links between natural soundscapes and human health and wellbeing, and there is evidence to suggest that our pro-environmental attitudes and behaviour might even reduce if we have fewer interactions with nature.
Simon Butler
Now we’ve got this framework for re-constructing soundscapes, there’s also an opportunity to look forwards and construct the soundscapes of the future, and perhaps think about how climate change might impact on our future soundscapes through changes in species distribution. And by understanding future changes, we can then start to think about the conservation actions that we might need to put in place to conserve and restore our natural soundscapes for the future generations.
Simon Butler
Although I lament the rise in technology and our reliance on that impacting on the time we spend out in nature, almost everybody has a recording device in their pockets. I’m using my phone to do that now, and we can use those to actually go out into nature and record our natural soundscapes in the environment where we live. Actually, citizen science data collected through live recordings of soundscapes could be really useful to understand spatial patterns in soundscape structure and temporal changes moving forwards.
Simon Butler
I think one of the key take homes from this is to recognise the benefits of natural soundscapes and to get outside and enjoy them in their current form. If they’re going to continue deteriorating, we know that biodiversity loss is expected to continue. Over the last 18 months, I think we’ve really grown to realise the benefits and the value of spending time out in nature, so although many of us have been locked down and kept at home, we’ve also had more opportunity to get outside and actually realise what’s on our doorsteps and the benefits that we can get from just taking a walk in the local park or in the habitat around us. And the great thing is they’re right there on our doorsteps, so get outside and enjoy them.
Noah Baker
That was Simon Butler from the University of East Anglia in the UK. This podcast was recorded and produced by Geoff Marsh, with a little bit of editing help from me, Noah Baker. We’d also like to say thank you to Walter Andriuzzi and Marian Turner. If you want to read more about Simon’s work, you can. We’ll put a link to the paper he discusses in this podcast in the show notes. It’s all free to access. We had a lot of fun making this podcast. And if you’d like to hear more like it then let us know. You can reach out to us on Twitter – @NaturePodcast – or email – podcast@nature.com.
Using sound to explore events of the Universe
Pioneers of sound
