Monitoring Ecosystems through Sound: The Present and Future of Passive Acoustics

Post provided by Ella Browning and Rory Gibb

AudioMoth low-cost, open-source acoustic sensor ©openacousticdevices.info

AudioMoth low-cost, open-source acoustic sensor ©openacousticdevices.info

As human impacts on the world accelerate, so does the need for tools to monitor the effects we have on species and ecosystems. Alongside technologies like camera traps and satellite remote sensing, passive acoustic monitoring (PAM) has emerged as an increasingly valuable and flexible tool in ecology. The idea behind PAM is straightforward: autonomous acoustic sensors are placed in the field to collect audio recordings. The wildlife sounds within those recordings are then used to calculate important ecological metrics – such as species occupancy and relative abundance, behaviour and phenology, or community richness and diversity.

The Pros and Cons of Passive Acoustic Monitoring

Using sound to monitor ecosystems, rather than traditional survey methods or visual media, has many advantages. For example, it’s much easier to survey vocalising animals that are nocturnal, underwater or otherwise difficult to see. Also, because acoustic sensors capture the entire soundscape, it’s possible to calculate acoustic biodiversity metrics that aim to describe the entire vocalising animal community, as well as abiotic elements in the environment.

The use of PAM in ecology has been steadily growing for a couple of decades, mainly in bat and cetacean studies. But with sensor costs dropping and audio processing tools improving, there’s currently a massive growth in interest in applying acoustic methods to large-scale or long-term monitoring projects. As very low-cost sensors such as AudioMoth start to emerge, it’s becoming easier to deploy large numbers of sensors in the field and start collecting data. Continue reading

New Research Shows Pretend Porpoise Sounds are Helping Conservation Efforts

Below is a press release about the Methods in Ecology and Evolution article ‘Estimating effective detection area of static passive acoustic data loggers from playback experiments with cetacean vocalisations‘ taken from Swansea University.

Harbour porpoise under the surface - I. Birks, SeaWatchFoundation

Harbour porpoise under the surface – I. Birks, SeaWatchFoundation

An examination into the detection of harbour porpoises is helping to give new understanding of effective monitoring of species under threat from anthropogenic activities such as fisheries bycatch and coastal pollution.

In a first study of its kind, Dr Hanna Nuuttila, currently at Swansea University’s College of Science – together with scientists from the German Oceanographic Museum, the University of St Andrews and Bangor University – revealed how playing back porpoise sounds to an acoustic logger can be used to assess the detection area of the device, a metric typically required for effective monitoring and conservation of protected species.

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Issue 7.7

Issue 7.7 is now online!

The July issue of Methods is now online!

This month’s issue contains two Applications articles and two Open Access articles, all of which are freely available.

– MO-Phylogenetics: A software tool to infer phylogenetic trees optimising two reconstruction criteria simultaneously and integrating a framework for multi-objective optimisation with two phylogenetic software packages.

– PHYLOMETRICS: An efficient algorithm to construct the null distributions (by generating phylogenies under a trait state-dependent speciation and extinction model) and a pipeline for estimating the false-positive rate and the statistical power of tests on phylogenetic metrics..

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