Butterflies could be about to be wiped out by extreme weather

The effect is probably already happening
 

Andrew Griffin

Monday 31 October 2016

Extreme weather could threaten the existence of Britain’s butterflies, according to a new study.

Heat waves, cold snaps and heavy rain have probably already contributed to crashing populations of butterflies, the scientists behind the study say. And that same effect is likely to continue.

While scientists have long known that climate change can cause lasting and intense damage to ecosystems, scientists know a lot less about the way that shorter spells of extreme weather can affect them.

The new study looked at data from the UK Butterfly Monitoring Scheme to explore how butterfly populations have changed. That data includes information on populations from more than 1,800 sites in the UK across 37 years.

The team found that rainfall level during the cocoon life stage of butterflies adversely affected more than a quarter of butterfly species in the UK.

But the greatest harm was caused by extreme heat during the "over-wintering" life stage, which had an impact on more than half the species.

Study co-author Dr Aldina Franco, from the University of East Anglia, said: "This may be due to increased incidences of disease or potentially extreme hot temperatures acting as a cue for butterflies or their larvae to come out from over-wintering too early and subsequently (be) killed off by temperatures returning to colder conditions."

Hot weather was found to benefit warmth-loving adult butterflies, leading to a positive population change in more than a third of species.

Continued