Not silent yet; the shifting sounds of spring

Date:
November 2, 2021
Source:
University of East Anglia
Summary:
Natural sounds, and bird song in particular, play a key role in
building and maintaining our connection with nature - but a major
new study reveals that the sounds of spring are changing, with
dawn choruses across North America and Europe becoming quieter
and less varied. An international team of researchers led by
the University of East Anglia (UEA) developed a new technique,
combining world-leading citizen science bird monitoring data with
recordings of individual species in the wild, to reconstruct the
soundscapes of more than 200,000 sites over the last 25 years.



FULL STORY ========================================================================== Natural sounds, and bird song in particular, play a key role in building
and maintaining our connection with nature -- but a major new study
reveals that the sounds of spring are changing, with dawn choruses across
North America and Europe becoming quieter and less varied.


==========================================================================
An international team of researchers led by the University of East Anglia
(UEA) developed a new technique, combining world-leading citizen science
bird monitoring data with recordings of individual species in the wild,
to reconstruct the soundscapes of more than 200,000 sites over the last
25 years.

Lead author Dr Simon Butler, from UEA's School of Biological Sciences, explained: "The benefits of nature contact are widespread, from improved physical health and psychological well-being to increased likelihood of participating in pro-environmental behaviour.

"Bird song plays an important role in defining the quality of
nature experiences but widespread declines in bird populations,
and shifts in species' distributions in response to climate change,
mean that the acoustic properties of natural soundscapes are likely
to be changing. However, historical sound recordings don't exist for
most places so we needed to develop a new approach to examine this."
Annual bird count data from North American Breeding Bird Survey and Pan- European Common Bird Monitoring Scheme sites were combined with recordings
for over 1000 species from Xeno Canto, an online database of bird calls
and songs, to reconstruct historical soundscapes.

The acoustic characteristics of these soundscapes were then quantified
using four indices designed to measure the distribution of acoustic
energy across frequencies and time. These indices are driven by song
complexity and variety across contributing species but quantify the
diversity and intensity of each soundscape as a whole.



========================================================================== Commenting on the study, published today in the journal Nature
Communications, Dr Butler said: "We found a widespread decline in the
acoustic diversity and intensity of natural soundscapes, driven by
changes in the composition of bird communities.

"These results suggest that the soundtrack of spring is getting quieter
and less varied and that one of the fundamental pathways through which
humans engage with nature is in chronic decline, with potentially
widespread implications for human health and wellbeing.

"Given that people predominantly hear, rather than see, birds, reductions
in the quality of natural soundscapes are likely to be the mechanism
through which the impact of ongoing population declines is most keenly
felt by the general public," he added.

The researchers say the relationship between changes in the structure
of bird communities and resultant soundscape characteristics is not easy
to predict.

Dr Catriona Morrison, a post-doctoral researcher in UEA's School of
Biological Sciences, conducted the analyses. She said: "In general,
we found that sites that have experienced greater declines in either
total abundance and/or species richness also show greater declines in
acoustic diversity and intensity.



========================================================================== "However, initial community structure and how the call and song
characteristics of species complement each other, also play important
roles in determining how soundscapes change.

"For example, the loss of species such as skylark or nightingale, which
sing rich and intricate songs, is likely to have a greater impact on the complexity of the soundscape than the loss of a raucous corvid or gull
species. Critically however, this will also depend on how many occurred
on the site, and which other species are present.

"Unfortunately, we are living through a global environmental crisis,
and we now know that the diminishing connection between people and nature
may be contributing to this," said Dr Morrison.

"As we collectively become less aware of our natural surroundings, we also start to notice or care less about their deterioration. Studies like ours
aim to heighten awareness of these losses in a tangible, relatable way
and demonstrate their potential impact on human well-being." The research
was supported with funding from UKRI Natural Environment Research Council.

========================================================================== Story Source: Materials provided by University_of_East_Anglia. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Morrison, C.A., Auniņs, A., Benkő, Z. et al. Bird
population
declines and species turnover are changing the acoustic
properties of spring soundscapes. Nat Commun, 2021 DOI:
10.1038/s41467-021-26488-1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211102125447.htm

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