Butterfly numbers are rapidly falling in towns and cities as home owners convert their gardens into driveways.
Charity Butterfly Conservation says the loss of gardens, plus pollution and development, has caused 25 species to decline faster in urban areas than the countryside. Applications to pave over front gardens for parking have soared by almost 50 per cent in two years, devastating the flowers and bushes that butterflies rely on for survival.
Professor Tom Brereton, head of monitoring at the charity, said: ‘The problem of people paving over their gardens for driveways has doubled in the last 20 years, because of the lack of parking spaces in urban areas. ‘In some towns and cities large gardens are being sold off for housing and in back gardens we are seeing fewer plants and more decking, extensions and barbecue areas. People are using more pesticides too, all of which are bad for butterflies.’
Research published by Direct Line last month showed successful applications for lowered kerbs to create driveways have risen by 49 per cent between 2013 and 2015, with 29,587 applications approved in 2015. Gardeners could use the same space to help butterflies by cultivating wild flowers and ivy, which they can use to hibernate in.
A report by Butterfly Conservation with the University of Kent also raises concerns over pollution, which can change the composition of city soil. Another concern is that brownfield sites, with areas of scrubland, bushes and wild flowers, are being built on.
The study, published in the journal Ecological Indicators, compared trends for 28 species in urban and countryside environments. Over a 20 year period, urban butterfly abundance fell by 69 per cent compared to a 45 per cent decline for butterflies in rural areas. The Small Copper and Small Heath declined much more dramatically, with a 75 per cent fall in urban areas and 23 per cent in rural areas for the former, compared to 78 per cent and 17 per cent for the latter.
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Cities and towns are also losing higher numbers of peacocks, red admirals and small tortoiseshells. Concerningly, caterpillars in urban areas become butterflies up to five days earlier than rural counterparts due to heat from buildings and cars. This could mean their life cycles no longer match up with the flowers they feed on for nectar.
Countrywide, butterfly numbers are down 51 per cent from 1976 to 2015. Lead researcher Dr Emily Dennis, of the University of Kent, said: ‘We used sophisticated statistical techniques to reveal that practically all butterfly species that we assessed were found to be struggling in urban areas, most likely due to the combined effects of habitat loss, climate changes and the intensification of land use.’