The Brilliant Butterflies project aims to reverse the long-term decline of butterfly and insect populations.
The London Wildlife Trust, along with Butterfly Conservation and the Natural History Museum, will transform 60 hectares of rare chalk grassland habitat for biodiversity across five special nature reserves in south London.
It will gather important data on invertebrate populations through pioneering DNA analysis technology. It will also implement a citizen science programme with 4,400 local residents.
The project aims to reverse the long term species decline of butterflies and other insects.