The Bats of Dartmoor’s Wooded Valleys
Although Dartmoor is most famous for its windswept uplands, the deep river valleys carved into the eastern side of the moor form their own unique ecosystem, supporting a wide variety of plants and animals. Among these, one of the most challenging groups to monitor are the bats, due to their nocturnal nature – but an ongoing study is gradually shedding more light on these secretive species.
Three of Dartmoor’s Wooded Valleys: Fingle Woods (River Teign) Three of Dartmoor’s Wooded Valleys: Bovey Woods (River Bovey) Three of Dartmoor’s Wooded Valleys: Ausewell Wood (River Dart)
The project began in 2015 when Dr. Matt Zeale and Andrew Carr from Bristol University led a volunteer effort to live trap, radio tag and track a population of Barbastelle bats living within the Bovey Valley woodlands. Over the course of that summer, several bats were tagged, and their behaviour was meticulously recorded, along with detailed information about the areas of woodland they selected for roosting.
A Barbastelle bat ready to be fitted with a radio tag
In the intervening years, the project has expanded in scope – new technologies, such as using infra-red CCTV to monitor roosts, has been trialled, and monitoring work has been carried out in other Dartmoor valley sites: Fingle Woods near Moretonhampstead and the Woodland Trust/National Trust’s newly acquired woodland at Ausewell near Ashburton. The value of these areas for bats is highlighted by the fact that all three have been shown to support at least 12 species – about 70% of all bat species resident in the UK!
In tandem with the ongoing fieldwork, the researchers at Bristol University have been modelling which characteristics of the valley woodlands are most critical for bats when it comes to selecting roosting sites, and using this to predict where else bats might be found within the valley system.
A remote bat detector, deployed as part of the monitoring project
With much of the UK’s wildlife under threat from climate change, development and intensive agriculture, Dartmoor’s wooded valleys can be seen as “refugia” – areas of land which by their geographical nature are sheltered to some degree from both climatic extremes and human disturbance, and which should continue to host species that have been lost across the wider countryside.
As well as providing a fascinating insight into bat behaviour, the data from the project is allowing land managers in the area to better understand how to protect bats during forestry work, and even how to manage sites with the aim of increasing the number of potential roosting sites for tree-dwelling species. This will ensure that the wooded valleys support a healthy and diverse bat population in the years to come.
Woodland Trust Assistant Site Manager Sam Manning and Dr. Andrew Carr conducting bat habitat assessments at Ausewell Wood.
On 5th November 2020, as part of the Fingle Lecture Series, Dr. Andrew Carr gave an online presentation summarising the latest research findings to emerge from the monitoring project. This was followed by a talk by local naturalist Tom Williams looking at his ongoing monitoring work and how the data gathered in the field compares with the predictions made by Bristol University’s model. For anyone who couldn’t attend the original event, or would like to see it again, the video can be watched below.
Text and images by Tom Williams