The UKBMS provides a wealth of information on the trends and status of butterflies across the UK. We provide annual, 10-year and long-term (series) trends for 56 species which can be found in the species accounts and the summary tables (UK or Country level).
Trend analyses are also performed for groups of butterflies and these are used as biodiversity indicators. These trend analyses tell us which species are increasing or declining across the UK, and help inform conservation by identifying priority species and their responses to management over time (The State of the UK’s Butterflies 2011).
The UK and country trend indices and the indicators are classified as ‘Official Statistics’ and are produced to the high professional standards set out in the Code of Practice for Official Statistics, which sets out eight principles including meeting user needs, impartiality and objectivity, integrity, sound methods and assured quality, frankness and accessibility. More information on the Official Statistics Code of Practice can be found at http://www.statisticsauthority.gov.uk/assessment/code-of-practice/index.html
In addition, the UKBMS data is widely used in research. Below are some of the recent highlights (since 2010) and a more extensive list of publications using data from the scheme is available here:
Butterflies and environmental change
Butterflies are a model taxon for studying the effects of environmental change, as demonstrated by large body of research results. Below are some of the recent highlights (since 2010) and a more extensive list of publications using data from the scheme is available here:
Traits and population trends
In conjunction with the Butterflies for the New Millennium project, the UKBMS shown that many species of UK butterfly have declined in both range and abundance. It isn’t all bad news, there are a number of species that have been expanding their ranges and/or showing increases in abundance. Regular updates in species status are being used to redefine the species which are future priorities for conservation action, including those Red Listed and threatened with extinction. The recent State of the UK’s Butterflies report has shown that the rate of decline in some of our rarer species has slowed down or even reversed in response to targeted conservation management, especially through agri-environment schemes.
Further to this is a body of research attempting to determine some of the mechanisms behind different population trends. For the High Brown Fritillary an allele effect is apparent with low growth rates at low pop densities, and immigration key in colony survival and species persistence.
There has been inconclusive evidence suggesting that a recently arrived parasitoid is responsible for the declines seen in Small Tortoiseshell across the UK, whilst earlier studies on the same species have shown that drought is also likely to play a role. After years of speculation about the life cycle and migration behaviour of the Painted Lady, a study ranging from northern Africa throughout Europe, has shown that they return to northern Africa in the autumn after a series of generations during which they make progressive northward, then southward movements through Europe.
Butterfly declines continue despite European Union targets to halt biodiversity loss. Both the range and abundance of many species have continued to decline across the UK from 2000-2010, but there are encouraging signs that some of our most threatened species are responding positively to conservation management. Fox et al (2011) in The State of the UK’s Butterflies 2011.
A new Red List of UK butterflies was compiled in 2010, with 19 species are classed as threatened. Amongst these, two are Critically Endangered, eight are Endangered and nine Vulnerable. Fox et al. (2010) in Insect Conservation and Diversity (doi: 10.1111/j.1752-4598.2010.00117.x)
An allele effect is evident in three quarters of High Brown Fritillary local populations, highlighting the need to increase resource availability in both occupied and unoccupied sites. Bonsall et al. (in press) in Ecological Applications (http://dx.doi.org/10.1890/13-0155.1)
Secrets of the Painted Lady’s journey from Africa and back revealed for first time. Using transect data along with radar technology and citizen science data, the hypothesised return journey of the Painted Lady is finally understood. Stefanescu et al (2013) in Ecography (doi: 10.1111/j.1600-0587.2012.07738.x)
A recent arrival of a parasitic fly to the UK is adding to the declines of the Small Tortoiseshell butterfly. Survival is lower in Small Tortoiseshell larvae where the parasitoid is present suggesting a role in the recent declines of this widespread butterfly. Gripenberg et al. (2011) in Ecological Entomology (doi: 10.1111/j.1365-2311.2011.01269.x)
Warm-adapted butterfly species tend to increase at northern, upland sites, consistent with an effect of increasing temperature across monitored sites in the UK. Morecroft et al. (2009) in Biological Conservation (doi: 10.1016/j.biocon.2009.07.004)
Scheme design and indicator development
The UKBMS is constantly evolving. The Wider Countryside Butterfly Survey is now a fully operational scheme, online recording is in place and new statistical techniques have been tried and tested to make use of more of the data collected and produce more accurate species indices.
The UKBMS is regarded as a gold standard with similar methods widely adopted across Europe. A recently published manual is helping new countries to develop butterfly monitoring. Van Swaay et al. (2012) in Manual for Butterfly Monitoring
UK and country-level indices are also used as biodiversity indicators. The indicators are split into wider countryside species and habitat specialists, and in England woodland and farmland butterflies are also assessed separately.
Butterfly data used to develop biodiversity indicators in the United Kingdom. Brereton et al. (2011) in Journal of Insect Conservation (doi: 10.1007/s10841-010-9333-z)
Survey launched to monitor butterflies in the wider countryside. Brereton et al. (2011) in Journal of Insect Conservation (doi: 10.1007/s10841-010-9345-8)
Power calculations for monitoring studies: a case study with alternative models for random variation. Elston et al. (2011) in Environmetrics (doi: 10.1002/env.1096)
Distance sampling and the challenge of monitoring butterfly populations. Isaac et al. (2011) in Methods in Ecology and Evolution (doi: 10.1111/j.2041-210X.2011.00109.x)
Indexing butterfly abundance whilst accounting for missing counts and variability in seasonal pattern Dennis et al. (2013) in Methods in Ecology and Evolution (doi: 10.1111/2041-210X.12053)