The tremendous scientific achievements of the long-running UK Butterfly Monitoring Scheme were celebrated at a special symposium at CEH in November 2016. Marc Botham recaps proceedings:

UK Butterfly Monitoring Scheme logoAs recorders completed their final butterfly counts on 29 September 2015, the last day of the monitoring season, a significant milestone was reached - the United Kingdom Butterfly Monitoring Scheme# (UKBMS), one of the world’s longest running ecological datasets, had been running for 40 years: an incredible achievement. The network across the UK has reached 2,436 sites and trends are now assessed for 57 of the 59 regular occurring butterfly species in the UK.

Statistical innovation has enabled the UKBMS to provide a wealth of world-leading research to understand the impacts of environmental change, particularly how climate change and habitat loss is affecting our wildlife. The success of the UKBMS is testament to the expertise and engagement of thousands of volunteers who have made this possible: a leading example of citizen science, even if the term wasn’t invented when the scheme started in 1976.

On 12 November 2016, the 40th anniversary was formally celebrated with a symposium hosted at the Centre for Ecology & Hydrology (CEH), Wallingford. The day, attended by 120 people, included a fantastic programme of talks covering the inception and history of the scheme; how the scheme has helped create and measure progress of environment policies; research on climate change; and the implications for conservation management. Global and future perspectives of the monitoring scheme were also discussed as we start to plan the development of the scheme for the next 40 years.

Following the talks, the achievements of some of the scheme's longest serving and most dedicated contributors were recognised. Awards were presented by Dr Martin Warren, Chief Executive of Butterfly Conservation (BC) for outstanding, long-term contributions to the scheme.

Delegates at the UKBMS 40th anniversary symposium
The symposium was well attended and included some of the longest-serving recorders, most active butterfly conservationists, ecologists and researchers, as well as some of those who have been part of the UKBMS since it began in the early 1970s. Photo by Colin Harrower.

Background to the UKBMS

The UKBMS is a long-term scheme monitoring butterfly populations across the UK. It is run as a partnership between CEH, Butterfly Conservation, the British Trust for Ornithology and the Joint Nature Conservation Committee. It was initiated at the CEH Monks Wood site in the early 1970s, then the Institute of Terrestrial Ecology (ITE). The population status of butterflies is calculated from counts from a network of fixed sites, including randomly selected 1km squares (as part of the Wider Countryside Butterfly Survey element of the UKBMS). More details on the scheme and the methods used can be found here. The resulting UKBMS dataset is one of the most important resources for understanding changes in insect populations and answering policy questions relating to status and trends in biodiversity, including the production of biodiversity indicators.

Graph showing decline of fabitat specialist butterflies

Graph showing decline of species of the wider countryside butterflies
UK Biodiversity Indicators show that, since 1976, populations of habitat specialists and species of the wider countryside have both declined significantly.

Overview of the day

The first presentation of the day was given by Dr Ernie Pollard, who, with colleagues, developed the primary survey method (butterfly line transects are also colloquially known as ‘pollard walks’) and operated it in the early years while he worked for the Institute of Terrestrial Ecology at Monks Wood. Ernie talked through the inception of the scheme, the reasons why it was considered important back in the early seventies and how the scheme was piloted at Monks Wood and nearby localities to develop a suitable standardized methodology which could be replicated at sites across the UK. Aside from being a fantastic presentation it was a real eye opener into the history of the scheme, some of the issues faced and the lack of technology we have all come to take for granted these days. Ernie also covered a small fraction of some of the interesting research he carried out on data collected in the early years of the scheme – indeed many of the research questions we address today Ernie had already started to ask and provide an insight to, providing a fantastic platform from which to work.

Ernie Pollard presenting at the UKBMS 40th anniversary symposium
Hugely anticipated was the first presentation of the day by Ernie Pollard who talked about the inception of the UKBMS for which he is credited: butterfly transects are also known as ‘pollard walks’, although Ernie was keen to point out that Norman Moore had inspired the idea and that he was helped by a fantastic team including David Elias, Mike Skelton and Jeremy Thomas. Photo by Colin Harrower.

Ernie’s talk was followed up by more excellent talks on the history and importance of the scheme by Dr Tom Brereton of Butterfly Conservation (BC) and Dr Keith Porter of Natural England (NE). Tom covered the important partnership developed between CEH and BC to bring together the formal Butterfly Monitoring Scheme developed and operated at ITE, and the independent transects being walked throughout the UK by reserve wardens, for example, to form the UKBMS as we now know it. He also illustrated the huge volume and quality of research articles that have utilized the data since 1976 (there have been around 150 peer-reviewed articles, together cited almost 10,000 times) and the immense dedication and support of thousands of volunteers who have made the collection of such important data possible.

Keith Porter then discussed how UKBMS data is used in policy as indicators of Biodiversity change and habitat quality – one of the most important outputs from the scheme – and how governmental bodies continue to support what is regarded a very valuable resource. Keith has been influential in the development and continued funding for the BMS and was presented with a small gift after his talk to acknowledge his long-term input as he nears retirement.

Tom Brereton presenting on the scientific contribution of UKBMS at the 40th anniversary symposium
Tom Brereton showcases the impressive scientific contribution of the UKBMS since it started. Photo by Colin Harrower.

At the close of these first three excellent presentations, participants were able to enjoy one of CEH’s buffets that are quickly reaching legendary status. As participants caught up with colleagues and friends there was a set of displays to showcase recent research and developments, for example, collecting habitat data on butterfly transects using drones by Dr Tom August and statistical developments currently helping bring together butterfly monitoring datasets from around Europe by Dr Reto Schmucki, both of whom are based at CEH's Wallingford site.

After lunch there were a series of presentations discussing the impacts of climate change on butterfly populations. Dr Marc Botham gave a fascinating overview of current and past research into the remarkable changes in butterfly flight periods that have coincided with climate warming over the 40 years of monitoring – some species such as the Orange-tip now fly up to three weeks earlier, on average, than they did when the scheme began. Dr Tom Oliver, now at the University of Reading, described his excellent research that was mostly conducted while he was at CEH on extreme climatic events, the resilience of butterfly populations to these events and how habitat characteristics such as fragmentation and homogenization affect this. Prof Chris Thomas gave an impressive overview of how species’ distributions have changed over the 40 years of monitoring and what mechanisms have driven these changes, as well as the variation in responses across different species – the effects of climate change are not straightforward, they are complex and require continued research, and the UKBMS has provided and continues to provide a valuable dataset to help achieve this.

Prof Chris Thomas presenting at the UKBMS 40th anniversary symposium
Chris Thomas delivered an excellent and thought-provoking talk on the complex effects and impacts of climate change on butterfly populations. Photo by Colin Harrower.

Following a short break, talks resumed with Prof Jeremy Thomas, who helped Ernie design and develop the UKBMS back in the early seventies, reviewing how the data from the UKBMS has helped to inform conservation management. Jeremy expertly reviewed decades of fantastic conservation research, including the successful reintroduction of our most specialized butterfly, the Large Blue, following its extinction in the late 1970s.

This was followed by two talks covering the future reach and development of the UKBMS. Chris van Swaay of the Dutch Butterfly Conservation and Butterfly Conservation Europe gave an overview of how many countries across Europe have already adopted the UKBMS method and how these datasets have been brought together successfully to produce biodiversity indicators across Europe such as the Grassland Butterfly Indicator. He then outlined some of the challenges of monitoring butterflies globally in habitats where the current methods employed in the UKBMS are not always suitable. In tropical rainforests for example, many butterfly species exist but are rarely seen because they spend much of their time high in the canopies. One group of tropical butterflies that feed on fruits are currently monitored by bait traps which offers one alternative method for monitoring butterflies in a standardized manner in such habitats.

Following Chris was Dr David Roy to talk about future perspectives – after 40 years of monitoring, what might the next 40 years involve? What are the priorities for developing the scheme further? The scheme already boasts a recent modernisation in terms of data collection (more than 80% of transects are now recorded online) and statistical analyses which utilise all of the data including from the recent Wider Countryside Butterfly Survey (WCBS).

Developments in data capture including apps and drones, better coverage of more species so we can report on all our UK species with confidence, wider collaboration to address future challenges such as climate change and biological invasions for example, were among a list of items contributing to David’s final slide depicting a manifesto for the future of the UKBMS and provided a nice positive outlook for the future.

A slide from David Roy's presentation at the UKBMS 40th anniversary symposium
Among the future directions and considerations for the UKBMS covered in David Roy’s talk, this slide certainly got the attention of the audience, many of whom have been recording butterflies for decades and would relish the opportunity to record some of the illustrated species on their walks in the future. Photo by Colin Harrower.

Awards and thanks

Dr Martin Warren closed the meeting with a few words covering the impact and highlights of the UKBMS before presenting awards, which included some of Richard Lewington’s amazing butterfly prints, to some of the most dedicated volunteers for their outstanding contributions to the UKBMS. These included:

Dr Ernie Pollard: a lifetime contribution to the scheme – apart from originating the scheme Ernie has walked three regular transects from 1973-1986 after which he moved to Kent and set up a new transect which he has walked annually since. He has covered 3,790 km and counted more than 80,000 butterflies, and has also written many scientific papers and books based on the UKBMS and butterfly monitoring in general.

Ernie Pollard was presented with a butterfly print at the UKBMS 40th anniversary symposium
Before the UKBMS begun Ernie was already researching butterflies: some early work looked at the life cycle of the White Admiral butterfly pictured in the Lewington print presented to Ernie for his lifetime contribution to the UKBMS. Photo by Jim Asher.

John Rowell: the most butterflies counted. John walks a number of transects on the Isle of Wight around Whippingham and Parkhurst Forest where annually some of the largest butterfly counts are regularly made. To date he has counted nearly quarter a million butterflies (222,259) since the late 1990s.

Mike Slater: the most transects walked. Mike began walking a transect at Ryton Wood North in 1991, and now walks 11 different transect routes around that part of Warwickshire. He conducted 223 transect walks in 2016 bringing his running total up to 2,816. He also serves as Chairman and Conservation Officer for the Warwickshire Branch.

Martin Warren presents Mike Slater with a butterfly print at the UKBMS 40th anniversary symposium
As well as walking the most transects over the last 40 years, Mike Slater has done a lot of work restoring and creating habitat for the Small Blue in the West Midlands and so a Lewington print with this species was chosen to thank him for his contributions to the scheme and butterfly conservation generally. Photograph by Jim Asher.

Richard Williamson: the most distance walked. Richard has walked the Kingley Vale National Nature Reserve transect in West Sussex since 1976. This is one of the longer transects in the scheme at 6km and Richard has walked 5,795km in the 40 years – a distance equivalent to walking from Paris to Pakistan.

Ian Woiwood and Dick Southwood: 40 years of walking transects – along with Ernie Pollard and Richard Williamson, Ian and Dick are the only recorders who started with the scheme in 1976 and are still walking transects today. Formerly Head of Rothamsted Insect Survey, Ian has walked his Potton Wood transect more than 900 times and counted more than 120,000 butterflies. Bure Marshes has been Dick’s main transect, which he has walked going on for 800 times since 1976. This is an important transect for one of the UK’s most restricted butterfly species, Swallowtail, and has provided important data to inform us how this species has fared over the last four decades. 

Ian Woiwood collects a butterfly print from Martin Warren at the UKBMS 40th anniversary symposium
Ian Woiwood collects his award from Martin Warren. Photo by Jim Asher.

As part of Butterfly Conservation’s coordination of the scheme and the thousands of volunteers that collect the data, regional coordinators were assigned in the 1990s. Regional coordinators are still volunteers but they take on a huge part of the data traffic, helping to coordinate, set-up, and prioritise transects in their region, as well as to validate and collate all the data collected before it is sent on to BC and CEH. Their work is crucial and original county recorders were all given awards for their years of hard work and dedication: Andy & Linda Barker (Hampshire & Isle of Wight), Bill Shreeves (Dorset), Ken Orpe (East Midlands), Laura Sivell (Lancashire), Mike Wilkins (Upper Thames), Andrew Graham (Gwynedd & Anglesey), Marjorie Brunt (Somerset & Bristol), Rob Parker (Suffolk), and Bill Dowty (Surrey).

The meeting was a great opportunity to showcase this important long-term monitoring scheme and CEH’s ongoing role in its success. The many fantastic and positive comments from those who attended also confirmed that it provided a fitting celebration of the expertise and dedication of individuals and organisations that have been closely involved over the past 40 years. 

Marc Botham and David Roy


The UKBMS is run by the Centre for Ecology & Hydrology, Butterfly Conservation, and the British Trust for Ornithology, in partnership with the Joint Nature Conservation Committee (JNCC), and supported and steered by Forestry Commission (FC), Natural England (NE), Natural Resources Wales (NRW), Northern Ireland Environment Agency (NIEA), and Scottish Natural Heritage (SNH).

UKBMS partners

Additional information

UK Butterfly Monitoring Scheme website

See a Storify summarising tweets from the 40th anniversary symposium