Broadcaster Sir David Attenborough has launched a £25m conservation project in the UK with a stark warning on the plight of the butterfly.
The BBC presenter said three-quarters of butterfly species in the UK had declined in the past 20 years.
Sir David was talking at the launch of Butterfly Word, in St Albans, Hertfordshire - a 26-acre site to house and protect thousands of butterflies.
It aims to counteract the decline caused by environmental changes.
Sir David said: "More than three quarters of British butterfly species have declined in the past 20 years, some of them very rapidly.
"That is worrying, not least because these declines indicate an underlying deterioration of the environment as a whole. For the sake of future generations we must take action now.
"Butterfly World is doing just that. It is putting the issues on the agenda and is seeking to help reverse this environmental catastrophe."
Work is due to begin on the site in the next few weeks, with the visitor attraction due to open its doors in 2011.
The site will be developed into the shape of a butterfly, with the dome as its eye.
It will incorporate underground caverns featuring tropical creatures including scorpions and spiders and there will be more than 10,000 tropical butterflies in flight at any one time in the walk-through centre.
Butterfly expert, Clive Farrell, who has developed the project, said: "Butterflies are like the canaries in the coal mine. When their environment is under stress, they are the first to suffer and disappear.
"During the 20th Century, five of Britain's butterfly species and 60 moth species became extinct. Drastic butterfly losses are continually being reported as we destroy their natural habitats at a frightening pace."