The United Kingdom has lost 150 animals and plants this century, ranging from lichens to butterflies and birds.
Some animals, such as the osprey and the white-tailed eagle, have been reintroduced from the Continent, but many of the lost species can never be reclaimed.
Sir David Attenborough, the naturalist and television programme-maker, said: "At least half were found only in the United Kingdom and have therefore been lost to the world for ever."
The full list has been compiled by groups that include the RSPB and the World Wide Fund for Nature to remind the Government of its wildlife and biodiversity commitments made at Rio de Janeiro three years ago.
Until 1983, visitors to Widewater Lagoon at Shoreham, West Sussex, could have marvelled at Ivell's sea anenome, Edwardsia ivelli. The fawn and orange-spotted marine animal, less than an inch long and sporting 12 tentacles, has vanished from its only known home, the victim of pollution or the loss of its shrimpy food source. Dr Paul Cornelius, of the Natural History Museum in London, said: "It may exist as spores but people have looked very closely on several occasions and failed to find it."
He believes the loss of a single species should be deeply regretted. "It would take a new Earth and a new Universe to be created for it to be replaced," he said.
A similar act of creation would also be needed for some of the 59 spiders and other insects, including the delicate black-veined white butterfly, Aporia crataegi, not seen in Britain since 1925.
More than 50 species of algae, including the slimy fruited stonewort, are also believed to have disappeared, with seven mosses and 13 flowering plants. Nearly 50 fungi and slime moulds have been lost to pollution and the destruction of ancient meadows. Slime moulds feed on bacteria and their loss may make trees more vulnerable to infection.
The loss of parasitic fungi, several of which are believed to have also disappeared because of the use of pesticides, may appear cause for few tears. But Dr Roy Watling, of the Royal Botanic Gardens, Edinburgh, says: "You get a knock-on effect. The fungus may be the special food source for a beautiful butterfly or a hideous beetle, and you have killed a whole ecosystem."
Many lost species are humble creatures such as ground beetles, species of wild bee, burrowing wasps and flies, including the dainty, or Norfolk damselfly, which was recorded as extinct in 1957.
Others are more conspicuous. Blair's wainscot, a moth, was last recorded in 1966 after its only known site on the Isle of Wight was destroyed by draining and burning for agriculture.
Gary Roberts of Butterfly Conservation says that the large tortoiseshell was so common in the last century that Victorian collectors believed its homes were too numerous to record. But the butterfly, a lover of sheltered wooded areas, was declared extinct in the British Isles two years ago.
The mouse-eared bat joined the funeral procession three years earlier. The females in Britain's last colony in West Sussex all vanished in 1974 and the last male died in 1990 aged 19. The reason the females suddenly died could have been the felling of a single tree in which they were breeding.
Burbot, a once-common eel-like fish in eastern England, was declared extinct in the late 1970s. It is believed to have suffered from overfishing by anglers and by pollution. The Kentish plover, which once bred around Dungeness, has been lost as a British bird since the 1930s.
