According to research by Butterfly Conservation (BC), the University of Kent and the Centre for Ecology and Hydrology (CEH), the majority of urban butterflies emerge earlier than their rural counterparts and are on the wing for longer.
This is thought to be the impact of the ‘urban heat island’ effect, as towns and cities are generally warmer than the surrounding countryside.
While farming intensification has had an impact on butterfly populations, the study suggests that urban life is more damaging, with increasing pressure to develop urban parks, gardens and brownfield sites, which act as an important refuges for butterflies and other wildlife.
The research shows that butterflies are sensitive to environmental change, with butterflies in urban areas emerging on average two days earlier than countryside butterflies, with urban Brimstone butterflies emerging five days earlier than those found in rural locations.
Flight periods for many of the species studied were also found to be slightly longer for urban butterflies than their rural counterparts.
The study compared trends for 28 species in urban and countryside environments. Over a 20-year period urban butterfly abundance fell by 69% compared to a 45% decline for butterflies in rural areas.
From 1995 to 2014 Small Copper abundance fell by 75% in urban areas compared to a 23% decline in rural areas. The Small Heath experienced an abundance decline of 78% for urban areas, compared to a smaller decline of 17% in rural areas.
Professor Tom Brereton, BC Head of Monitoring, said: “Seeing butterflies each summer is a vital part of the quality of life for millions of people in the UK.
“The study shows that in urban areas where most people live and experience the natural world butterflies are in even more trouble than in our intensively farmed countryside. We must act now to ensure that we manage the environment to maintain the very things we cherish.”
Conservation group BC is now calling on the Government to help safeguard urban butterflies in order to prevent further decline.
Dr Nigel Bourn, BC Director of Conservation Science, said: “To fulfil on their green commitments, we hope the Government can add this urban indicator to the suite of others they support and develop policies that will help turn around the fortunes of our urban butterflies as one measure of how well they are doing in this aspiration.
“Improving the urban environment is something many of us can make a real contribution too, leaving bits of garden as wild areas, using less chemicals and gardening with wildlife in mind.”
“Combined with all our efforts in gardens more can be done locally in our parks and greenspaces. The same basic principles of wildlife gardening should be adopted across the country as a matter of common sense.”