Urban gardener: Wings of change

I'm sitting in a packed room at the Royal Society and extinction is on everyone's mind. It's a press launch for Butterfly World, a pioneering conservation project and visitor attraction for St Albans, Hertfordshire. The opening speech by Professor Jeremy Thomas, whose previous research helped to save the Large Blue butterfly from extinction in the UK, reveals that almost three-quarters of Britain's butterfly population has declined over the past 20 years – some of them very rapidly. The interdependence between butterflies, moths and plants is so finely tuned that many will simply not survive without the other and their extinction will almost certainly have devastating effects on other plant and animal species.

Next up is the project's founder, businessman and environmentalist, Clive Farrell whose passion for lepidoptery, the study of butterflies and moths, has seen him create a number of butterfly houses in Britain and abroad. He likens butterflies to the canary in the coalmine, being the first to suffer when the environment is under stress. "During the 20th century, five of Britain's butterfly species and 60 moth species became extinct," he explained. "Butterfly World is designed to bring the public into direct contact with some of the most fragile and beautiful wildlife in the world and send out a clarion call on behalf of this endangered treasure."

Flanking Farrell are Sir David Attenborough and Professor David Bellamy. When they lend their support to a campaign, you can guarantee it will make headlines. "These declines indicate an underlying deterioration of the environment as a whole," says Sir David, backing up the sentiments of the previous speakers.

Phase one of the project, laying the foundations for the £25m scheme, is imminent. The biome, some 100 metres in diameter and 17 metres high, will cover a Mayan-inspired lost civilisation and become not just the biggest butterfly house in the world, but perhaps the most significant visitor attraction-cum-conservation project in the UK. Within easy access of the M25, Butterfly World is expected to attract almost a million visitors a year. The biome will contain 250 species and 10,000 butterflies in the air at any one time. Some areas will be submerged to accommodate caverns where spiders, millipedes and scorpions will be on display and leaf-cutter ants will also be allowed passage across dining tables via a protective tube to stop them scoring a bit of lettuce from your sandwich en route.

The grounds outside have been designed by the eminent landscape designer Ivan Hicks who has drawn inspiration from the butterfly's profile using the biome as its eye. A number of gardens and rich meadow areas will rejuvenate wildlife-poor habitats to provide a unique educational, scientific and recreational resource. Being so close to the M25 early trials and surveys of natural colonisation will indicate whether it will be safe to introduce endangered species to the area.

There will also be Future Gardens (futuregardens.org), 12 competition gardens that will be on display from June to September each year with a strong bias toward sustainability. Founded by the same team who created The International Festival of the Garden at Westonbirt, Future Gardens will offer innovative artists and designers the freedom to experiment with ground-breaking ideas for a sustainable future, the first gardens being on display in June 2009, concluding phase one of Butterfly World's development.

Farrell and his team are hoping that a butterfly effect will help limit the damage to the planet and offset the cataclysmic extinction event that some scientists believe is already under way. The fact that we need help from "the little things that run the earth" as much as they need ours simplifies the message. Do nothing to stop the decline of butterflies and the outlook for the plant and animal kingdom is bleak. At what cost do we ignore the silent cavalry's bugle?

www.butterfly-world.org