Developing and launching a wider countryside butterfly survey across the United Kingdom

Abstract

Many butterfly species that were historically common throughout the UK are thought to have declined due to land use intensification, whilst others have increased regionally due to climate change. Population trends in these species are inadequately assessed by current monitoring programmes: the UK Butterfly Monitoring Scheme (UKBMS) mainly samples semi-natural habitats; coarse-scale distribution recording under-estimates declines in population abundance. We designed a scheme (the wider countryside butterfly survey—WCBS) to provide unbiased abundance trends for widespread butterfly species across the whole countryside. The WCBS has been developed over a 3 year pilot study, culminating in a UK-wide roll out in 2009. After testing a range of survey methods, the scheme involves visiting randomly selected 1-km squares at least twice during July–August and walking a linear transect route, counting the number of individual butterflies seen within 5 m. A method for volunteer recorders to collect abundance data on non-lepidopteran insects was also tested. The results of the first year of the WCBS and future plans for the scheme will be described.