She’s banged the drum for the Gurkhas, she’s the ambassador for an initiative to combat climate change and waste – but most recently, actress and keen gardener Joanna Lumley has turned her attentions to the plight of the humble butterfly.

Backing this year’s Big Butterfly Count, the world’s biggest survey of butterflies organised by Butterfly Conservation and Marks & Spencer, Joanna explains: “I’ve been fascinated by butterflies ever since being brought up in the Far East where they were, like many things there, huge, bright and extraordinary.

“The great heartbreak is to see how few there are today. Looking out on my garden now, and walking up and down it as I do every day, I’m not seeing any.

“This huge, scientific survey is actually counting the effect of mankind upon the natural world.”

The public is being asked to take 15 minutes to participate in the count, which runs from July 20 to August 11 – prime time for butterfly activity – to help identify trends in species that will help in planning how to protect butterflies from extinction, as well as understanding the effect of climate change on wildlife.

Butterflies react very quickly to change in their environment, which makes them excellent biodiversity indicators. Almost three-quarters of UK butterfly species have decreased in population during the last decade, while the number of UK’s large moths has crashed in the past 40 years, according to a recent reports by a group of leading conservation organisations.

“The predictions are that numbers will be down again this year,” says Butterfly Conservation surveys manager Richard Fox.

“As butterflies had such a bad year last year because of the wet weather, it’s likely that fewer offspring will emerge. The weather last year would have been a major contributing factor but there are other things going on. They need suitable habitats to thrive.”

The Butterfly Conservation offers the following tips to attract butterflies to your garden:

  • Choose sunny, sheltered spots when planting nectar plants, because butterflies like warmth.
  • Select different plants to attract a variety of species.
  • Prolong flowering by deadheading regularly, mulching with organic compost and watering well.
  • Don’t use insecticides and pesticides which kill butterflies and many pollinating insects.
  • Grow plants which will attract butterflies including buddleia, Verbena bonariensis, lavender, perennial wallflower, marjoram, phlox, nasturtium, aster, sweet rocket, lobelia and herbs including chives, thyme and mint.

For more details, visit bigbutterflycount.org.