In nature, there are changes that are obvious -a fire, for example- and other more subtle ones -climate change or the entry of an invasive species-, but that in the long run can generate as much or more impact on the environment. To prevent them from being irreversible, a Spanish scientific team is working on an experimental early warning system that serves to detect incipient changes in ecosystems by analyzing the sounds of nature.
“If something is disturbed, even if it is not visible to the naked eye, it is quite likely that it will end up affecting part of the biodiversity that produces noise, be it birds, insects, mammals or plants. The idea is that this system serves as a canary in the mine", Joaquín Lahoz, a researcher at the Pyrenean Institute of Ecology (CSIC) who leads, together with the biologist Begoña García, the experimental project 'Bioacustic' in the National Park, tells this newspaper. of Ordesa and Monte Perdido.
His initiative is one of the 35 highly innovative research projects that in 2022 received a grant of 120,000 euros from the BBVA Foundation. With part of that money, since July of last year they have placed some 25 acoustic sensors at different points in the park. “Ordesa's pilot system focuses on the effects of climate change because we know that mountain systems are very susceptible to it. In addition, this park is a very diverse place, and numerous previous studies have already been carried out in it, which enhances its attractiveness for testing this system”, explains García.
These devices, which remain attached to trees or posts, record one minute in ten, day and night, every day. Before they cost a thousand euros, but five years ago open hardware came out and today they are worth about 100, which allows them to be used on a much larger scale. “We plan to put two or three dozen more, even in the water, to record the sounds of fish and invertebrates,” Lahoz clarifies.
Among the criteria being considered for its location are trying to cover a wide spectrum of habitats -black pine forest, beech forests, scrub areas or meadows at different heights- and that they escape the noise generated by humans, avoiding incidentally a possible invasion of their privacy or that they can take the memory cards (as has already happened to them).
After compiling a year of recordings, their biggest challenge is being able to detect among those "giga and giga of audio" significant changes that go beyond the natural variability that occurs in multiple environments throughout the different parts of the world. day or seasons. To do this, they are working on the development of mathematical methods capable of measuring in the computer those deviations that go beyond what is expected and sound the alarm if they detect an anomaly.
This is where the "great novelty" lies with respect to other previous soundscape studies. According to Lahoz, what has been customary up to now in soundscape studies is to contrast the soundtrack of a habitat where alterations are recorded due to an external phenomenon -hunting, felling or grazing, for example- with a similar one in which no to see what differences there are. “Here we are thinking about changes in the future, therefore we cannot observe them nor do we have anything to compare with. We do not know which species can give the alarm signal. It will be the mathematical models that allow us to appreciate when the acoustic landscape is leaving what we think is normal”, he says.
The team hopes to be able to start analyzing the files in the fall to get the first results later. Meanwhile, they are working on another project that combines the investigation of the acoustic landscape and the thermal landscape with drones equipped with thermal cameras in five mountain areas of the Iberian Peninsula and the Canary Islands: Sierra Nevada, Sierra de las Nieves, Guadarrama, Garajonay and Ordesa. "This will also allow us to make comparisons, because Ordesa is very different from Sierra Nevada or a park in the Canary Islands, where there is never snow," they say.
