RSK Biocensus has a rich history with supporting and leading research of all shapes and sizes
Our ecologists love to tackle a project that is a little bit different, so, when we were asked to assist in the tree climbing for an exciting new project using bioacoustics, Principal Consultant Ecologist Ruth Morton and Principal Ecologist Leanne Cooke jumped at the opportunity to get involved!
What is Bioacoustic Monitoring?
Bioacoustic monitoring is a burgeoning field in conservation, with potential that is growing exponentially thanks to unabating advances in technology. This technique focusses on listening to the natural soundscape and inferring the presence or absence of certain species based on what can be heard.
William Cresswell’s PhD project at Bristol University (supported and funded by Rainforest Connection, the Mammal Society, and Huawei) is using this bioacoustic technology to develop a monitoring technique for the conservation of red squirrels and better understand their use of vocalisations.
The most important requirement for effective conservation action is information, and for red and grey squirrels this is certainly the case
Removal of greys is the only way to protect reds where they overlap, but trapping must be well-targeted to avoid stressing local red populations. Data are needed to understand where grey squirrels are expanding their ranges and to inform management of these to protect red ‘strongholds’ where the populations are holding on. Traditional, manual survey methodologies are labour intensive as they require, experienced observers. Also, data based on surveys using indirect indicators like dreys and signs of feeding are not always reliable as it can be difficult to accurately discern between the two species in this way. To avoid these issues camera traps are often used, set up in front of feeding stations although these setups also have their own shortcomings. Camera traps are power and data hungry, and as a result require frequent visits to change batteries and SD cards, making long-term monitoring more difficult (and expensive). More importantly there is a risk associated with using feeding stations in areas where Reds and Greys overlap (the areas that are most in need of monitoring) as these sites can act as a point of squirrelpox transmission. Acoustic monitoring has the potential to solve many of these issues as it is completely non-invasive, recorders can be low-cost and able to record autonomously for long periods of time and there may be scope to automate large parts of data analysis by developing an AI model (a convolutional neural network) trained on labelled data they have collected, that will be able to automate this analysis.
Trialling the use of soundscape recordings
This PhD project is trialling the use of soundscape recordings to survey for the two species of squirrel and particularly to monitor for grey squirrel invasions into red stronghold sites using a combination of methods.
Firstly ‘AudioMoths’ a small, cheap, battery-powered recorder developed by British research group Open Acoustic Devices, designed specifically for bioacoustic monitoring. Secondly, recorders designed and built by their project partners Rainforest Connection. Originally designed to automatically detect illegal logging in tropical rainforests by listening for the sound of chainsaws, these recorders have 3G connectivity allowing for data to be sent remotely and solar panels to keep the recorders running with little-to-no maintenance.
Ruth and Leanne from the RSK Biocensus Scottish team, travelled to Penrith to assist with the tree climbing required for the installation of these recorders in a forest home to a large red squirrel population.