Blown away

Butterflies cannot survive climate change. Peter Marren reports on the fight to save these most fragile of insects

"Butterflies are harder to conserve than golden eagles," says Martin Warren, chief executive of the Dorset-based charity Butterfly Conservation.

"Butterflies are harder to conserve than golden eagles," says Martin Warren, chief executive of the Dorset-based charity Butterfly Conservation.

Warren's point is that if an eagle has enough space and is left alone, you don't need to do anything. There may be lean years, but they can cope. And they live for a long time.

Butterflies are different. "They may be small, but they have big problems," Warren says. They are short-lived. Their whole life-cycle takes place in no more than a year, and the adults usually live for only a few weeks. Butterflies have to be successful every year, or they die out. And if their habitat is isolated amid farmland or suburbs, they tend to stay dead.

Butterflies are more complicated than they seem. Each has to find a suitable place to lay eggs, the caterpillar needs to find enough to eat and avoid its many enemies, and - crucially in Britain - stay warm and disease-free. The chrysalis has to blend in with its surroundings to avoid being eaten. And the butterfly has a busy life, feeding, fighting and finding a mate in the often fleeting sun - and now with a chronic shortage of wild-flowers.

To save butterflies, says Warren, you need to provide. They need the right amount of grazing. They need open woods with flowery glades, so bushes need to be cut regularly. Some visit gardens, but most are not wanderers. Gardens can be useful filling stations, but they are not the solution.

Earlier this month, Butterfly Conservation hosted the largest-ever conference on butterflies and moths, featuring 300 experts from 22 countries. At the event there were sad stories. Michael Samways from South Africa told of blue butterflies whose rocky habitat was threatened by invasive thickets of bramble introduced by an expatriate vicar who fancied some blackberries.

Martin Konvicka from the Czech Republic spoke of a place called Milovicky Wood, once the best place for woodland butterflies in the entire country. It had been fenced and stocked with deer to provide hunting for the Communists. At the fall of the Berlin Wall, the butterfly experts moved in. They found plenty of trees and deer - but few butterflies. Most had died out, victims of shade and over-grazing.

The familiar threat to butterflies, as with other wildlife, is from the fragmentation of their habitats through intensive agriculture and logging. But now butterflies are also threatened by climate change. Europe is 1.4C warmer now than in 1905. Computers predict a rise between 4C and 8C over the next century.

Butterflies are among the first insects to respond to change. The sooty copper is already vanishing from parts of southern Spain where it is now too hot, but is establishing itself in Scandinavia. Of a recent sample of 63 non-migratory butterflies, more than half were found to be moving northwards.

In Spain, where nearly all the country's butterfly hot-spots are on mountain ranges, climate change may already be a greater threat then agriculture. The Nevada blue, which is confined to the Sierra Nevada in southern Spain, is likely to become the first recent European butterfly extinction. The area is getting hotter and drier, and the Nevada blue is running out of mountain.

Most British butterflies live in the lowlands, so climate change may be less of a threat. Indeed, it is good news for some species, like the speckled wood, which is extending its range north. But there are fears for our only upland butterfly, the mountain ringlet, especially in the Lake District where it is confined to the hill-tops.

Despite the problems, there was cause for optimism at the conference. The developed world is edging away from universal intensive farming - for example, the Environmental Stewardship Scheme introduced by Margaret Beckett in March marks a shift in subsidies from production to conservation. Monitoring by Butterfly Conservation's volunteers showed that the scheme's forerunner, Countryside Stewardship, was starting to reverse the decline of several threatened species.

But the main reason for cheers was that the conference proved that butterflies matter. The many short presentations made it clear that butterflies are becoming a research priority across the world.

They have become conservation's canaries, a litmus test of environmental damage. Butterflies (and moths) are sensitive to change, far more than big animals or plants. Proportionately more British butterflies have declined or become extinct than birds or wild-flowers And they decline fast.

At the same time they are far and away the best-studied insects on earth. They are the only group of insects with "base-line data" on which monitoring systems can be based. Hence, as scientists seem to agree, butterflies are worth watching. For what hurts butterflies is likely to hurt the planet.

People are starting to realise how important it is to have a healthy butterfly population, says Martin Warren. "Butterflies in profusion tell us nature is happy." And you can't help noticing they make people happy, too.

Butterfly Conservation website: www.butterfly-conservation.org. For conference details e-mail lcowling@butterfly-conservation.org