Doomsday for butterflies as Britain warms up

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The Independent Online

At least 30 of Britain's butterfly species face extinction or an alarming drop in numbers because they are failing to cope with the effects of global warming.

At least 30 of Britain's butterfly species face extinction or an alarming drop in numbers because they are failing to cope with the effects of global warming.

A team of seven biologists and ecologists has warned that the numbers of some internationally rare species, such as the Large Heath and Purple Emperor butterflies, will fall by up to 77 per cent. Eventually, they could be wiped out.

Their study, published by the Royal Society, is one of the most pessimistic assessments yet about the impact of climate change on Britain's butterfly population. It contradicts the widespread belief that native butterflies will prosper in a warmer climate, expanding their range northwards and enjoying much longer summers.

"There's no silver lining in this data," said Richard Fox, a co-author of the study and spokesman for the Butterfly Conservation Society. "What we will see here is a retreat and, potentially, a mass extinction in the slightly longer term, of many of our familiar species."

Over the past few years, Red Admirals, Orange-tips and Small Tortoiseshells have been seen earlier in the spring and surviving for several weeks longer each autumn – suggesting that butterflies would generally benefit from climate change.

However, the researchers, led by Dr Jane Hill, a biologist at York University, noticed that many more butterflies had failed to spread during the 1990s, even though average temperatures were beginning to rise.

Disturbed by these results, they re-examined data collected by the Butterfly Conservation Society and the latest computer models on climate change to assess exactly how well 35 butterfly species could survive over the next 100 years.

They found that a few species, such as the Ringlet and the Marbled White, were already prospering, moving northwards and further up-hill as the summers became warmer during the 1990s. But for the vast majority of those studied, the situation will be more serious.

As climate change takes hold over coming decades, northern species living in northern England and Scotland, including the Western Isles, and will lose two-thirds of their habitats. In southern England, butterflies will lose a quarter of their habitats.

For some species, the future is particularly stark. Along with the Purple Emperor and Large Heath butterflies, the Mountain Ringlet, a small, rare butterfly which lives in Scotland, will lose 69 per cent of its habitats. The Black Hairstreak, a very rare species mostly confined to the East Midlands, will lose at least half of its normal habitats.

The Marsh Fritillary, which is regarded as the most important butterfly in Britain because of its rarity, will lose nearly a third of its already scarce habitats on Scottish islands such as Islay and on Salisbury Plain.

"We know from the work we've done that the vast majority of butterflies haven't responded in a positive way to climate change so far," Mr Fox said.

"We may get some butterflies from the south colonising us, but what this paper shows is that our butterflies are going to become much, much rarer."

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