Butterfly Conservation and Marks & Spencer have launched a national Planting for Butterflies campaign to encourage people across the UK to introduce butterfly-friendly plants to their gardens.
Mike Dilger, wildlife reporter from the BBC Television's The One Show, marked the launch by helping Bristol Grammar School students create a butterfly garden in the school's grounds.
Butterfly numbers in the UK have been declining for decades and in recent years this trend has been accelerating. Data collected by Butterfly Conservation volunteers show several once common species have declined dramatically over the last decade. Numbers of Small Tortoiseshell have declined by 68 per cent and the Peacock by 30 per cent during the 2000s.
Mike said: "Butterflies are beautiful and intrinsically valuable. They are sensitive to environmental change and their well-being tells us a lot about the health of the countryside.
Sadly, development and intensive farming have caused a significant drop in numbers over the last 50 years.
He added: "Five species of butterfly have already become extinct in the UK and more than half of the 56 remaining species are threatened with extinction. Planting for Butterflies is a chance to reverse this decline. Just put some Lavender in a pot or a bit of Buddleia in your flower bed and you can help make a difference."
Sir David Attenborough, President of Butterfly Conservation, says he is aware there are far fewer butterflies in his own garden these days.
He says: "Butterfly numbers are falling. Butterfly Conservation scientists have demonstrated that these declines can be reversed. If you change the environment to help butterflies, all sorts of other wildlife benefits too. Nature comes back to life."
The top five nectar plants that Butterfly Conservation is urging people to plant are:
Perennial Wallflower (Bowles Mauve)
These plants should all be in full bloom by July to coincide with this summer's Big Butterfly Count (16 to 31 July).
Butterfly Conservation is hoping to persuade tens of thousands of people to participate in the event which it hopes will be the world's biggest-ever butterfly count. It will help scientists determine where butterflies are thriving and where others face extinction.
Butterfly Conservation and M&S will be joining forces with the National Schools Partnership to encourage schools to take part in the Big Butterfly Count.
Members of the public will be able to record their sightings online.
The Planting for Butterflies launch marks the second year of Marks & Spencer's partnership with Butterfly Conservation. M&S will offer a range of butterfly-friendly lavender plants for customers to buy in store, with a donation from the profits going to Butterfly Conservation.
The partnership between M&S and Butterfly Conservation is part of the retailer's eco-plan, Plan A, to be the world's most sustainable retailer by 2015.
Richard Gillies, M&S Director of Plan A, commented, "We want to lead the way in making a positive contribution to the environment and society across everything we do and everything we sell. We want to make it as easy as possible for our customers and children across the UK to help butterflies. Now is the perfect time to get into the garden and start planting for butterflies so that come summertime butterflies will have the perfect environment to thrive."
Butterflies and moths are very sensitive to environmental change, which makes them a very good indicator of the health of the countryside. They are essential for the pollination of plants, and caterpillars provide food for many birds and other wildlife. If the UK lost all of its butterflies and moths, farmers would see a big drop in numbers of other wildlife including birds, and negative impact on crop yields.
Find out more about gardening for butterflies.