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Britain’s butterflies facing worst declines in 40 years amid heatwave and hosepipe ban

- Copyright: Helen Atkinson / Yellowsnapper 2012
- Copyright: Helen Atkinson / Yellowsnapper 2012

Britain’s butterflies could face the worst declines in 40 years, conservationists have warned, as the relentless heatwave withers plants just as gardeners are banned from using hosepipes.

Experts are worried that populations will suffer a similar catastrophic crash as happened after the scorching summer of 1976, when butterfly numbers fell by an average of nearly 60 per cent.

The 1976 summer was the hottest since records began over 350 years ago when temperatures topped 89.6F (32C) for 15 consecutive days across much of southern England, causing the worst drought in 150 years.

Although this year’s heatwave has not reached that level, water companies including United Utilities have already started to impose hosepipe bans and restrictions, leaving it harder for gardeners to keep their plants fully soaked.

The charity Butterfly Conservation is warning that without the leaves for caterpillars to feed on, the next generation of butterflies will starve to death, and by next year, numbers will plummet.

A marbled white resting on a stalk - Credit: Rob Blanken
A marbled white resting on a stalk Credit: Rob Blanken

Butterfly Conservation scientist Richard Fox said it was important for gardeners to keep watering their plants in the hot weather.

“The 1976 was the worst drought there had been since records began and it did have a very significant impact on butterflies,” he said.

“Almost all species crashed and that was related to the death of plants. In drought conditions, plants and trees lose their leaves, and without them the caterpillars will just starve to death.

“We’re now at the uncertain and rather scary point of not knowing whether that is about to happen again. If this heatwave continues into next month we really could see a repeat of 1977.

“Watering plants is important so they can keep flowering and providing nectar, which gives butterflies the energy to keep going, and also for breeding.”

The small tortoiseshell which has suffered serious declines  - Credit: Will Langdon, Butterfly Conservation
The small tortoiseshell which has suffered serious declines Credit: Will Langdon, Butterfly Conservation

Today the charity launches its Big Butterfly Count, which encourages people to spot and record 17 species of common butterflies and two day-flying moths for the next three weeks.  

More than three-quarters of the UK’s butterflies have declined in the last 40 years with some common species, such as the Small Tortoiseshell, suffering significant slumps.

However although big declines could happen next year, the combination of a cold winter and warm, settled late spring is likely to boost populations in the short term, with the Holly Blue, the common whites, Red Admiral and Common Blue all expected to increase in 2018.

Sir David Attenborough is encouraging people to take part in the Big Butterfly Count - Credit: Helen Atkinson
Sir David Attenborough is encouraging people to take part in the Big Butterfly Count Credit: Helen Atkinson

Butterfly Conservation President Sir David Attenborough said that watching for butterflies not only generates important data but also provides precious time out from the stresses of life.

“I have been privileged to have witnessed some truly breathtaking wildlife spectacles in far-flung locations but some of my most memorable experiences have happened when I’ve been simply sitting and watching the wildlife that lives where I do,” he said.

“Spending time with nature offers us all precious breathing space away from the stresses and strains of modern life, it enables us to experience joy and wonder, to slow down and to appreciate the wildlife that lives side-by-side with us.” The RSPB also encouraged gardeners to leave water out for the birds, which also suffered dramatic declines following the 1976 summer.

A chalkhill blue and a marbled white  - Credit: Will Langdon, Butterfly Conservation
A chalkhill blue and a marbled white Credit: Will Langdon, Butterfly Conservation

Harry Bellew, RSPB spokesperson, said: “While we revel in the unusual hot weather, it may be having a hidden impact on our favourite birds.

“Despite it being too early to tell the effect the weather has had on birds, past research has shown us that prolonged dry spells can be bad news for birds as it reduces the number of bugs for birds to feed on.

“Leaving out a supply of fresh clean water offers birds a vital lifeline when most natural water sources have dried up.”

The Big Butterfly Count runs from 20 July to 12 August. To take part find a sunny spot anywhere in the UK and spend 15 minutes counting the butterflies  then submit sightings online at www.bigbutterflycount.org  or via the Big Butterfly Count app.