Butterfly numbers remained at a low ebb in Scotland this summer but the common white species bucked the trend, results from the Big Butterfly Count revealed.
The majority of species studied as part of the citizen science scheme saw their Scottish populations rise this summer in comparison to 2015, but most were still below the counts in previous years.
The white butterflies – the Green-veined White, Large White and Small White, all recorded large year on year increases in Scotland.
The Green-veined White proved to be the most abundant Scottish butterfly during the mid-summer survey, with numbers up by 452% in comparison to last year. The Small White saw its numbers rise by 150% and the Large White also experienced an increase of 114%.
The Speckled Wood, which has become much more widespread in Scotland over recent decades, enjoyed a good summer. The butterfly’s numbers were up by 106% compared with 2015 to reach its highest levels in Scotland since the Count began.
Scottish participants saw an average of just eight butterflies per count this summer, slightly up on last year but well below the 11 per count spotted in 2013.
These falls came despite the UK experiencing warm and dry weather conditions that usually help butterflies to thrive.
But common species such as the Ringlet, Meadow Brown, Small Tortoiseshell and Red Admiral all struggled with numbers falling in comparison to last summer.
Numbers of the colourful Small Tortoiseshell have now dropped in Scotland from an average of 3.3 individuals per count in 2013 to just 0.5 per count in 2016, a six fold decrease over three years.
Across the UK as a whole the majority of butterfly species studied as part of the scheme saw their populations fall this summer with some producing their worst numbers since the Big Butterfly count scheme began, despite the UK experiencing weather conditions that usually help them thrive.
Reasons why butterflies have struggled despite favourable summer weather conditions are as yet unclear.
Butterfly Conservation’s Head of Recording, Richard Fox, said: “The drop in butterfly numbers this summer has been a shock and is a bit of a mystery. When we have cold, wet summers, as in 2012, we expect butterfly populations to plummet, but that can’t have been the case this year.
“The summer months were warmer than usual, yet most Big Butterfly Count participants saw fewer butterflies. Perhaps the very mild winter had a negative effect, or the cold spring, or perhaps the impacts of intensive farming and pesticides are really hitting these common species now.
“The importance of Big Butterfly Count is that it takes place every year over a long period; the longer it goes on the more we can learn about the causes that are driving the declines and in some cases, increases of our beautiful butterfly species. We are really grateful to the many thousands of people across the UK who do their bit to help butterflies by taking part in the Big Butterfly Count each summer.”
More than 36,000 people took part in this year’s Count, spotting around 390,000 butterflies across the UK during the three-week mid-summer recording period.
The Big Butterfly Count helps Butterfly Conservation find out how the UK’s common species are faring and how to best protect them in the future.
The Big Butterfly Count is sponsored by Waitrose and John Lewis. Tor Harris, Head of Sustainability and Responsible Sourcing at Waitrose, said: “Treading lightly on the environment is so important to us at Waitrose and that’s why we were passionate about supporting the Big Butterfly Count this summer – a great initiative that encourages people throughout the UK to play a key role in providing a better understanding of the butterfly population and with it the wider environment.”
Stephen Cawley, Head of Sustainability and Responsible Sourcing at John Lewis, said: “At John Lewis we are passionate about supporting local communities and putting something back in and so as part of our schools’ programme, Bringing Skills to Life, we’re pleased to have supported the Big Butterfly Count over the summer months. It’s projects like this nationwide study that help future generations to learn about science in an exciting way – at the same time, they are undertaking valuable research into what’s happening to our environment.”
Results can be found at www.bigbutterflycount.org
Big Butterfly Count 2016 – top 10 Scotland species ranking
- Green-veined White
- Ringlet
- Small White
- Meadow Brown
- Speckled Wood
- Small Tortoiseshell
- Six-spot Burnet
- Large White
- Common Blue
- Red Admiral
