One of Britain 's best-known seabirds, the puffin, is being wiped out by invading fast-growing alien plant species because of global warming.

Scientists have discovered the tree-mallow is choking puffin breeding sites on Scottish islands and have warned that the plant could soon start killing off other seabirds, such as herring gulls and cormorants.

Tree-mallow, Lavatera arborea, which grows mainly in Mediterranean countries, was once confined to only a few UK outcrops. But now the plant has begun to spread as a result of global warming. This year was the northern hemisphere's hottest on record. Polar bears and Arctic seals are suffering. In southern England frogs have started to spawn and autumn leaves have failed to fall.

'The plant has already covered a couple of islands so quickly that puffins cannot make their nests on the ground,' said Dr René van der Wal, of the Centre for Ecology and Hydrology, in Banchory. 'They cannot burrow in the soil and make nests. The result has been a catastrophic decline in puffin breeding. On Craigleith, near North Berwick, the numbers of burrows in which puffins breed plunged from 28,000 in 1999 to 14,000 in 2004 and the drop has continued this year. This is now the most dramatic example of an alien plant invader affecting wildlife in Britain,' he told The Observer.

The Atlantic puffin, Fratercula arctica, has a black back and white underparts, a flattened, brightly-coloured bill, and red and black eye-markings with bright orange legs. It is one of the nation's most distinctive and popular birds and is often photographed with sand eels - its favourite food - hanging out of its bill. The record is held by one bird which was found with 61 eels in its beak. But the advancement of the tree-mallow has added new fears for the future. First Craigleith succumbed to the plant, now the plant has started colonising other Scottish isles.

'The puffin only makes things worse for itself,' added van der Wal. 'It breaks up the ground, providing a perfect place for tree-mallow seeds to take root. The bird provides a home for tree-mallow which then prevents them breeding. Nature can be cruel.'

At present, only puffins have been affected by the tree-mallow's spread. However, researchers warn other ground-nesting seabirds could soon be affected, including herring-gulls, black-backed gulls and cormorants.

'There is a lot the public can do to help,' added van der Wal. 'They can send us photos of coastal areas where tree-mallow is growing, for example. We need to find out how quickly it is spreading.'

Getting rid of the plant may be tricky, although scientists do have a cunning plan: import neutered rabbits. 'Islands with rabbits do not have tree-mallow. Rabbits rip up their shoots before they can take proper root. And rabbits and puffins get on pretty well. However, too many rabbits could cause real damage and erosion - so we would neuter them first. It's simple really.'