Butterfly species in decline due to climate change


MANY COMMON butterfly species have declined in recent years due to unseasonal weather.

Butterflies are highly sensitive to changes in the environment, acting as an early warning indicator of the threat climate change poses to biodiversity.

“The poor weather conditions in the early part of the summer had a dramatic impact on the populations of species such as Green-veined White and Speckled Wood (the multi-brooded species) – whose earlier broods would have been adversely affected by weather conditions,” said Dr Liam Lysaght, the director of the National Biodiversity Data Centre (NBDC).

“These two common species suffered a decline of almost 50 per cent in populations between 2011 and 2010. We don’t have data in yet for 2012 but feedback . . . is that populations are down on last year,” he said.

The research delivering this data comes not from scientists but from the general public through the Irish Butterfly Monitoring Scheme.

Set up in 2007 by the NBDC, based at Waterford Institute of Technology, the scheme enables the public to report butterfly species by following online instructions at the site ( butterflies.biodiversityireland.ie) or via the Identify Irish Butterflies smartphone application.

Although the monitoring scheme has not been running for long enough to draw statistically significant conclusions in relation to climate change, it noted that uncharacteristic weather in 2011 resulted in lower abundances of more common species.

Other insect species are also sensitive to changes in climate, the NBDC said, including bees. The Irish Pollinator Initiative ( pollinators.biodiversityireland.ie) trains the public to monitor the emergence dates of bees.

Bee emergence dates are thought to reflect the knock-on effect of earlier springs.

Dr Lysaght said that records were set in 2011 for the earliest ever emergence of six different bee species.