The NBMP is the only UK-wide programme that monitors bats and changes to their populations. There are 17 resident bat species in the UK, and the data gathered by hundreds of dedicated volunteers enables the production of population trends for 11 of these at UK and country levels.
Background
The NBMP is a partnership between JNCC and Bat Conservation Trust (BCT). The Country Nature Conservation Bodies (CNCBs) fund additional surveys for species with country interest and with more limited distribution.
The monitoring programme has run annually since 1996 and JNCC became involved in 2001. We are a major funder for the programme and help develop and promote the project and the data it produces, and act as a policy interface.
NBMP would not be possible without the dedication and support of thousands of talented volunteers. Almost 1,000 volunteers survey approximately 1,700 transect every year. In 2022, volunteers spent a total of 13,700 hours completing approximately 3,800 surveys. Using the Heritage Lottery Foundation figures, the time volunteers dedicated to NBMP in 2022 was valued at around £200,000. It is also estimated that were it possible to find enough professional ecologists to do the same amount of surveys, that would cost 2-3 times as much.
Why do we monitor bats?
Bats are important indicator species and an important component of UK biodiversity, accounting for more than a quarter of the UK’s native mammal species. Bat species have suffered long-term population declines and range contractions and are vulnerable to multiple pressures such as habitat loss and degradation. Consequently, they are highly protected by environmental laws and international agreements.
Although there was no systematic data collection before the 1990s, available evidence, including from DNA sampling, indicates that there have been significant historical declines in bat populations dating back to at least the start of the 20th century, for some species much further back than that. Overall bat populations have stabilised and some have been slightly increasing since the 1990s. As this coincides with when legal protection was granted to all UK bat species resulting in a reduction in disturbance and loss of roosting, maternity and hibernation sites, it is believed that the two are linked.
The survey results contribute directly to informing policy and assessing performance against national and international agreements, as well as a wide range of published research that examine applied environmental questions.
Data contribute to JNCC’s annual official statistics on the status of UK bats and to UK Biodiversity Indicators C4a and C8. These published trends provide evidence for the conservation status of bats and help inform future conservation action and policy.
Bats are strictly protected species and data from the NBMP provide an important source of evidence for reporting under international agreements such as the Berne Convention.
Other influential publications that rely on the scheme data include the State of Nature report.
Sampling approach/how are the data collected?
The programme consists of four core surveys: Field Survey, Waterways Survey, Roost Count and Hibernation Survey, each designed to monitor a selection of the UK species. NBMP uses standardised methods to help ensure data are comparable over time and between locations. Some species are covered by more than one survey. Additional surveys that form a part of NBMP include Sunset Survey, Woodland Survey, British Bat Survey (BBatS) and NightWatch.
The Field and Waterways Surveys involve surveyors walking pre-determined transects and making note of all bat activity picked up by a bat detector - a device that converts the high frequency bat calls to a frequency audible to human ear. Each bat species has a distinct sound “signature”, and so it is possible to identify the bats from the calls they make along with visual clues of the bats in flight.
The Roost Count and Hibernation Surveys rely on volunteers discovering a site occupied by bats, and counting and identifying the bats that use the site.
The Sunset Survey is the entry-level survey that anyone can participate in – regardless of their prior experience – and does not require a bat detector. It is the perfect way of starting out with surveying bats, and the participants can contribute useful data, especially by discovering new roosting sites.
The Woodland Survey targets barbastelle bats, which are woodland specialists. This survey only takes place at protected sites (Special Areas for Conservation) where one of the reasons for the designation is the presence of this species.
BBatS and NightWatch are new surveys currently being rolled out. They use monitoring devices, fixed to suitable structures, that automatically record bat calls. The recordings are then analysed to identify all bats that passed the device during the night.
How and where data/results are available to stakeholders
The results are published annually, usually in May, in an annual report and accompanying data products. Survey data products are also uploaded onto the National Biodiversity Network (NBN) Atlas for open access, and BCT may be able to provide more detailed bespoke data in response to specific requests.
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