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Research into extreme weather effects may explain recent butterfly decline

Increasingly frequent extreme weather events could threaten butterfly populations in the UK and could be the cause of recently reported butterfly population crashes, according to research from the University of East Anglia (UEA).

Researchers investigated the impact of Extreme Climatic Events (ECEs) on butterfly populations. The study shows that the impact can be significantly positive and negative, but questions remain as to whether the benefits outweigh the negative effects.

While it is well known that changes to the mean climate can affect ecosystems, little is known about the impact of short-term extreme climatic events (ECEs) such as heatwaves, heavy rainfall or droughts.

Osgur McDermott-Long, PhD student and lead author from the School of Environmental Sciences at UEA, said: “This is the first study to examine the effects of extreme climate events across all life stages of the UK butterflies from egg to adult butterfly. We wanted to identify sensitive life stages and unravel the role that life history traits play in species sensitivity to ECEs.”

The researchers used data from the UK Butterfly Monitoring Scheme (UKBMS), a high-quality long-term dataset of UK butterfly abundances collected from over 1,800 sites across the UK, spanning 37 years, to examine the effects of weather data and extreme events (drought, extremes of rain, heat and cold) on population change.

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