Long wet summers killing off butterflies

Britain’s butterfly population has been depleted by two successive rainy and cooler summers.

The UK Butterfly Monitoring Scheme says that butterfly numbers are at the lowest level for more than 25 years.

Some species have suffered severely.

The Brown Fritillary and the Woodwhite have been reduced to very few colonies and in some parts of the country they may even have become extinct.

In the last two years, summers have been very wet and so butterflies cannot go in search of mates or nectar from flowers. The sun makes them even more active.

Minister for Wildlife, Huw Irranca-Davies believes that global warming is part of the problem, making butterfly breeding grounds endangered.

Dr Tom Brereton, who is in charge of monitoring at Butterfly Conservation, said that most species only fly when temperatures reach 15-16 C.

Several butterfly conservation projects were launched last year around the country but there were not enough butterflies to benefit from them.

However, Dr Brereton said, we have seen a quick recovery in butterfly numbers before, certainly amongst the more common varieties.

Some butterflies actually prospered somewhat last year.

The Large Heath grew in numbers by 66 percent and the Ringlet grew by 35 percent, partly because they will fly in rain and partly because they live in bogs, which normally remain damp.

There was also a 91 percent increase in the numbers of the Northern Brown Argus, Dr Brereton added.

He also said that there is concern about the decline in Small Heaths, with numbers down 15 per cent, Small Tortoiseshells numbers are down 45 per cent and Small Coppers are down 29 per cent.

Four varieties of butterflies suffered the most during 2008.

Painted Ladies fell by 81 per cent, Clouded Yellows by 90 per cent and a fall of 65 percent occurred in Black Hairstreaks and 66 per cent in Wood Whites.

Fewer country fields full of brightly coloured wild flowers, a different style of forestry management and concentrated agriculture have also damaged the butterfly population.

Gardeners can help the butterfly population recover and thrive, Dr Brereton pointed out.

It would certainly help if home gardens became more organic by cutting the amount of chemicals in fertilisers and pesticides.

Plenty of brightly coloured flowers help and the larvae, that is to say the caterpillars, are herbivorous so gardeners should not mow their lawns so frequently.

Planting ivy provides butterflies with a good place to find nectar and some species will survive in ivy through the winter.