Acoustic sensors enable efficient and non-invasive monitoring of a wide range of species, including many that are difficult to monitor in other ways. Although they were initially limited in application scope largely due to cost and hardware constraints, the development of low-cost, open-source models like the Audiomoth in recent years has increased access immensely and opened up new avenues of research. For example, some teams are using them to identify illicit human activities through the detection of associated sounds, like gunshots, vehicles, or chainsaws (e.g. OpenEars).
With this relatively novel dimension of wildlife monitoring rapidly advancing in both marine and terrestrial systems, it is crucial that we identify and share information about the utility and constraints of these sensors to inform efforts. A recent study identified advancements in hardware and machine learning applications, as well as early development of acoustic biodiversity indicators, as factors facilitating progress in the field. In terms of limitations, the authors highlight insufficient reference sound libraries, a lack of open-source audio processing tools, and a need for standardization of survey and analysis protocols. They also stress the importance of collaboration in moving forward, which is precisely what this group will aim to facilitate.
If you're new to acoustic monitoring and want to get up to speed on the basics, check out these beginner's resources and conversations from across the WILDLABS platform:
Three Resources for Beginners:
- Listening to Nature: The Emerging Field of Bioacoustics, Adam Welz
- Ecoacoustics and Biodiversity Monitoring, RSEC Journal
- Monitoring Ecosystems through Sound: The Present and Future of Passive Acoustics, Ella Browning and Rory Gibb
Three Forum Threads for Beginners:
- AudioMoth user guide | Tessa Rhinehart
- Audiomoth and Natterjack Monitoring (UK) | Stuart Newson
- Help with analysing bat recordings from Audiomoth | Carlos Abrahams
Three Tutorials for Beginners:
- "How do I perform automated recordings of bird assemblages?" | Carlos Abrahams, Tech Tutors
- "How do I scale up acoustic surveys with Audiomoths and automated processing?" | Tessa Rhinehart, Tech Tutors
- Acoustic Monitoring | David Watson, Ruby Lee, Andy Hill, and Dimitri Ponirakis, Virtual Meetups
Want to know more about acoustic monitoring and learn from experts in the WILDLABS community? Jump into the discussion in our Acoustic Monitoring group!
Header image: Carly Batist
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Description | Activity | Replies | Groups | Updated |
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Awesome stuff!! Interested in what kind of recorders you are using and how are you sync'ing them for the TDOA? |
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Acoustics | 1 year 10 months ago | |
Jamie's tip piqued my curiosity, so I bought what I thought might be what Jamie was talking about. It is an SK-001 as detailed here (not my video) for SGD4 or thereabouts.... |
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Acoustics | 1 year 11 months ago | |
Hi Eric, Dropping in a reply we had over on Linkedin here. Annoyingly I can't do a snazzy embed of the comment - will fix that!Anton Baotic shared: I guess it depends on... |
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Acoustics, Early Career | 1 year 11 months ago | |
Thank you @carlybatist , @Freaklabs and @MK . The inputs are very useful and I am progressing on my project based on that. Appreciate a lot. |
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Acoustics, AI for Conservation | 1 year 11 months ago | |
Fascinating article, combining machine learning and acoustical signals to correlate coral reef health.https://www.sciencedirect.com/science... |
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Acoustics, AI for Conservation, Marine Conservation | 1 year 11 months ago | |
Hi Julien,I use this mic for my raspberry pi setup and it works well picking up bird species singing in our garden while the mic and raspberry sit under our roof tiles.Greetings,... |
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Acoustics | 1 year 11 months ago | |
Koen, Hi - the config for the audiomoth looks fine (you could put a high-pass filter on to cover frequencies 12-96 kHz only). The scheduler is not set (you have 0 files per day... |
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Acoustics | 2 years 2 months ago | |
Would anyone know about the recommended number of months to conduct acoustic monitoring of sharks. This is part of a small grant project.... |
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Acoustics | 2 years 2 months ago | |
We've been using 18650 lithium ion protected cells in our BAR recorders since 2013. The protected cells are great because the protection circuitry kicks in to disconnect the... |
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Acoustics | 2 years 4 months ago | |
Unfortunately, the ASA is currently planning to do an in-person meeting only. Things may change if the COVID situation doesn't improve in May, but it is hard to predict at... |
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Acoustics | 2 years 4 months ago | |
Hi all, For everyone's reference but also a new one for your list Tessa (just checked and it isn't there yet) - Fuentes, M., Salamon, J., Zinemanas, P.,... |
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Acoustics | 2 years 6 months ago | |
Hi Nicole-- We've already chatted about this function, and I think the answer is "quite a bit" for a lot of deployments. The more accurately the proposed function... |
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Acoustics | 2 years 7 months ago |
Calculating species abundance from Acoustic Data
26 January 2016 1:22pm
26 April 2016 11:59am
Hi Stephanie,
This is an interesting thread. For those interested in the topic, and forgive me for the blatant self-promotion of work, a Biological Reviews 2013 paper on the topic can be downloaded here http://www.creem.st-and.ac.uk/decaf/outputs. Additional case studies papers as well as a more general public paper in Acoustics Today are also available for download from the link. This link is the outputs page from project DECAF, dedicated to estimating animal density from passive acoustic fixed sensors, using cetaceans as case studies. The methods have been far more developed and used in the cetacean community, but I suspect a wider use in terrestrial environments will occur in the coming years. A key hurdle is perhaps the dynamics involved in acoustic cue rate production, but the issues will be much easier to tackle in terrestrial environments than in the marine environments we have been working on.
Hope this is helpful,
Tiago
26 April 2016 12:13pm
Hi Tiago,
Thank you for sharing this paper and contributing your experience to the thread. Blantant self promotion, as you put it, is more than welcome when the work you're pointing to is such a helpful resource!
Cheers,
Stephanie
Funding and Job Opportunities
26 November 2015 2:21pm
26 February 2016 3:26pm
The Elephant Listening Project at the University of Cornell is looking a Postdoctoral research to study forest elephants in central Africa using a combination of field observations and acoustic recordings. More info.
A novel citizen science approach for large-scale monitoring of bats
5 February 2016 12:00am
Report outlines 2016's most pressing conservation issues
3 February 2016 12:00am
Must-Have Books on Bioacoustics
31 January 2016 4:26pm
(News Article) Listening to the sounds of nature 24-7 in Alberta
31 January 2016 4:16pm
Ecological Acoustics (Ecological Informatics special issue)
29 December 2015 9:56pm
26 April 2016 10:45am
Hi,
I think Steffen provided a good summary of the challenges.
IMO, the two most promising methods of estimating animal density from acoustic monitoring are the "generalised random encounter model" (gREM) and an extension of spatially-explicit capture-recapture (SECR). These potentially solve Steffen's problems 2 and 3, i.e. linking acoustic counts to abundance (2), and converting abundance to density (3).
gREM, although theoretically possible, may be tricky in practice (especially obtaining an estimate of how wide an animal's acoustic signal is). See here:
http://onlinelibrary.wiley.com/doi/10.1111/2041-210X.12346/abstract
SECR is potentially very powerful, but depends on an independent estimate of calling rate (a problem Yu Shiu rightly picked up on). I think this would be entirely possible for a species you can find and observe (e.g. a frog or common bird species), but difficult for lots of cryptic, low density species (e.g. tigers!, as Courtney mentioned). See here:
https://www.researchgate.net/publication/272371302_A_general_framework_for_animal_density_estimation_from_acoustic_detections_across_a_fixed_microphone_array
However, gREM and SECR do not help with Steffen's first point (1) "quantifying the number of vocalisations from a stream of acoustic recordings". Others might be able to advise on the best approaches there. Perhaps this is primarily a software / data processing problem...?
In terms of sampling design (as Mariane and Courtney were interested in), it depends what your aims are. For occupancy (which is not equal to abundance/density), similar design principles to camera-trapping are fair (but taking into consideration Yu Shiu's point that the effective sampling area might be MUCH larger for an acoustic sensor than a camera trap, so camera spacing will have to be larger too). For gREM, you can fairly flexible about sampling design (repeated detections of the same individual are not a problem), but your sensors should be set randomly in space (with respect to animal movement), not along trails etc. For SECR, you don't have to set your sensors randomly, but sensors must be close enough together for repeated detections of the same call in multiple sensors simultaneously (this design constrasts, therefore, with an occupancy design).
Hth,
Ollie