Collecting On-Farm Biodiversity Data with Bioacoustics
5 July 2024This article is part of the Climate Change & Carbon Research Briefings series. More articles in the series can be found below:
- Understanding Natural Capital Markets
- Faba Beans for Alternative Protein and Reducing Monogastric Carbon Footprint
- Applicability of Slurry Separation and Acidification on Farms in Scotland
- Advancing Agricultural Practices, Reducing Emissions and Ensuring Sustainable Growth in the Face of Climate Challenges
- Making Sense of Soil Carbon
- Are Methane Inhibitors a Silver Bullet for the Sustainability of Beef and Dairy?
- Mitigating N2O Emissions and Enhancing Yields with Inhibitors and Liming
- Low Emissions Livestock Breeding - The What and the Why
This document gives an overview of bioacoustics and the exciting opportunities for using these devices to discover key species using habitats on your farm. With an understanding of bioacoustic sensors, farmers and land managers can be ahead of the curve in exploring this and other methods for monitoring biodiversity as this is phased into Scottish agricultural support. This document explains what is involved, including a case study of the ongoing research at SRUC’s Hill and Mountain Research Centre.
What is bioacoustic monitoring?
Scotland’s new agricultural support system will put an increasing focus on farmers and crofters delivering benefits for nature and climate change. The new Tiers 1 and 2 of payments will require meeting a set of environmental conditions, with options to take further action to receive enhanced payment levels. To access higher tiers, farmers and crofters will likely be asked to collect some evidence themselves, to show that their biodiversity management has been successful.
One way to monitor biodiversity on farm is through the use of bioacoustics. These are listening devices which can be left outdoors in farm habitats to collect data on a range of species. Through capturing audio data from the environment, bioacoustics can identify individual species, as well as give insight into their distribution, physiological state, and behaviour. Sensors can record the calls of specific target species, and some can detect ultrasonic sounds (useful for bats and other hard-to-detect species). Bioacoustics are very commonly used to identify birds, bats, and increasingly used to monitor frogs, toads, and insects, potentially of huge value to farm biodiversity projects looking to boost pollinator numbers. Similar to camera traps, this method is non-invasive and can be deployed for weeks or months at a time, making it useful for detecting species that are rare or difficult to spot visually. Bio-acoustic monitoring is scalable, repeatable, and data can be stored and analysed at a later date.
Figure 1: An AudioMoth listening device. Powered by 3 x AA batteries, 58x48x15mm.
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Case study: SRUC Hill & Mountain Research Centre
At SRUC’s Kirkton & Auchtertyre upland demonstration farms, near Crianlarich, a team of SRUC researchers is investigating how technology such as acoustic sensors can be used to collect biodiversity data. The sensors they are using (called Audiomoth) can be set to different frequencies, allowing them to choose to record calls made by birds or, at higher frequencies, the inaudible calls of bats.
The sensors are placed in different habitats across the farm and collected after five days of gathering audio data. The recordings are stored on memory cards and then processed by specialist software on a computer, which indicates the type and number of occurrences of different species each sensor has recorded. The process of identifying birds based on their calls is very similar to that used by apps available on mobile phones, and both approaches use the same USA-based database of bird calls to identify each bird species.
Figure 2: Map of habitat types at the SRUC Hill & Mountain Research Centre.
One issue of using Audiomoth or mobile phone apps is that the software used to identify the bird species will take any sound occurring in the frequency range that has been set and match it to whichever bird species appears to be the “best fit.” This means that a small number of incorrect identifications, known as false positives, can occur in any list of recorded species, for example birds and other species which do not have ranges in Scotland. However, the advantage of using the Audiomoth sensors over the mobile phone app is that the Audiomoth sensor can be set to different levels of sensitivity when recording the call information. In addition, when processing the data, the software used can also be set to different levels of confidence when seeking to identify the species making each call. This helps to weed out these false positives and give an accurate register of species on the farm.
What is the value of this data?
So far, the AudioMoth sensors at SRUC’s demonstration farms have correctly identified many species which had previously been recorded using other means, meaning the acoustic sensors are working well. In addition, repeated recordings over time indicate the presence of Noctule bats on the farms, one of the largest UK species, which had not been previously recorded. Using bioacoustics has helped this research project confirm the presence of a wider number of species than had been previously identified.
As part of the ongoing research, the research team is looking to see what combination of sensitivity and confidence settings are best suited to Scotland’s upland environment. They are also considering introducing a cut-off value for how many times a given species should be recorded before the software before confirming the presence of each species, to ensure bioacoustics tools are generating accurate lists of species present. The more that farmers and crofters are asked to collect data on their own farms and crofts, then the greater the importance will be in ensuring that such data collection is seen as robust. Bioacoustics could be a simple and effective way for the agricultural sector to demonstrate the biodiversity value associated with their land management, if the data reported by these tools is trustworthy. This research is therefore looking to produce a simple guidance document on how to use AudioMoths to best effect.
What is next for bringing this technology onto farms?
Of course, this method is limited to species which generate sound, and target species can be drowned out in noisy environments. For accurate results, a suitable sampling strategy should be used, involving a number of sensors deployed at strategic locations. Bioacoustics can be costly (including sourcing equipment, deploying and retrieving it from the field, and storing and analysing data) although some innovative, lower cost options exist (e.g. WilderSensing). Another potential way around high analysis costs may be to use open-source apps and citizen science platforms such as Merlin SoundID. Farmers interested in exploring these methods of biodiversity monitoring should get in touch with a local ecologist to discuss next steps.
The ongoing research project at the SRUC demonstration farms is part of a wider project “Seeking multiple benefits from natural carbon stores in the uplands” (SRUC-D4-1), funded under the Scottish Government’s Strategic Research Programmes, 2022-2027. The project seeks to measure the carbon sequestration, biodiversity value, and flood mitigation potential of upland areas of Scotland, understanding the interlinkages of these three areas and how upland farms can best contribute to all three of these public goods.
Brady Stevens, SAC Rural Business & Economics Consultant, SAC Consulting
and
Davy McCracken, Head of SRUC’s Hill & Mountain Research Centre, SRUC
Further Reading
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