Butterflies and beetles blow hot and cold as climate change makes mark

Published on Thursday 5 November 2009 21:27

BUTTERFLY species that usually like warmer climates south of the Border have been found in growing numbers in parts of Scotland, a 15-year study has shown.

Scientists believe that some species of butterflies are migrating north as climate change causes warmer temperatures.

The same research has revealed certain types of beetle known to prefer colder weather have started to decline in the Cairngorms. The scientists behind the study monitored species living at 12 sites between 1993 and 2007 – making it the most major review into changing species behaviour yet undertaken across the UK.

Three of the sites monitored were in Scotland – a high, mountainous site in the Cairngorms, and two areas of rolling hills in Glensaugh, Aberdeenshire, and Sourhope, in the Borders.

Over the period of the study, peacock butterflies started appearing in growing numbers in Glensaugh, the warmest of the three sites, and at Sourhope.

Other butterfly species also grew in number at Glensaugh, including the dark green fritillary, common blue, ringlet and small pearl-bordered fritillary.

Meanwhile, in the Cairngorms, beetle species including Calathus melanocephalus, Patrobus atrorufus and Calathus micropterous declined in number as temperatures rose.

Temperature monitoring showed that all 12 sites became warmer over the 15 years covered by the research.

The authors said in the report: "The invertebrate data suggest that some warm-adapted species are tending to increase and spread northwards, whereas some typical of cooler northern and upland areas are declining."

Dr Mike Morecroft, principal climate change specialist at Natural England and lead author of the report, told The Scotsman he thought global warming was responsible for the changes.

"I think it's the best explanation," he said. "It's hard to say it's completely cast iron, that it couldn't be anything else, but we know butterflies are a very temperature-sensitive species and we know the temperatures have increased."

He added: "Climate change is one of the major contemporary issues in ecology and presents the most profound challenge for conservation in the coming decades.

"The need for reliable monitoring of environmental change, both physical and biological, is greater than ever."

Co-author Don Monteith, of the Centre for Ecology and Hydrology, said "consistent patterns" had started to appear.

"There has been a pattern of decline in some moorland species of beetles and these are linked to cold, wet habitats," he said.

The work has been carried out by the UK Environmental Change Network, which has the backing of 14 UK government departments and agencies. The network aims to identity and understand long-term changes in UK ecosystems.

The research paper is published today in the journal Biological Conservation.