The number of species on the endangered list in Britain has almost doubled in 13 years, according to a new study.
Otters are among the species on the list of endangered mammals
There are now 1,149 species of plants, mammals, birds and insects, and 67 different types of habitat under threat from climate change and human activity.
Grahame Madge, of the RSPB, said there must be serious action to restore a "healthy countryside rich in wildlife".
Among the species at risk are the skylark, dormouse, red squirrel, grass snake and several species of bat.
The list has been compiled by the UK Biodiversity Action Plan (UK BAP) and was the result of two years research by more 500 wildlife experts and a large number of volunteers.
They blame a range of factors including farming techniques and inappropriate rural and urban planning.
DEFRA say the increase is largely due to the fact that "more accurate information on threatened species has been gathered".
The number of endangered habitats has gone up from 49 in the last survey done in 1994. Among those under threat are hedgerows, orchards, pine woodlands, meadows and sand dunes.
The Priority Species and Habitats list also includes 14 kinds of freshwater fish like the common sturgeon and Atlantic salmon, and 18 mammals, such as pine martens and water voles.
But the largest proportion of species are invertebrates like insects and spiders, with more than 400 at risk.
Matt Shardlow, director of Buglife, told the BBC's Today programme that species like the moonshiner beetle, glutinous snail and Viking sword fly must be protected.
"What we need to do is to address the habitats as well as the species, start to put some of these habitats back into the countryside, get them into good condition so that the species are able to spread and thrive," Mr Shardlow said.
"Every public office holder has to have a regard for what is on this list and make sure they're doing their bit to conserve it."
Researchers looked at the rate of decline of a species, in particular where the UK was responsible for a large proportion of the entire international population.
Fifty-nine species and sub-species of birds (up from 27) are now said to be endangered, including the lesser spotted woodpecker and the black grouse.
Mr Madge said much of the decline was due to the intensification of farming and the swallowing up of marshes, hedgerows and other areas for agriculture.
"Take the grey partridge - it should be on every farm in Britain. You should be able to walk less than a mile anywhere in the countryside and hear one," he said.
"It's a bird that our rural ancestors would have heard every day and now you have to make a real effort to find one.
"That's why our ultimate aim must be to restore a healthy countryside rich in wildlife."
UK BAP is a partnership of government bodies and wildlife charities set up after Britain signed the international Convention on Biological Diversity in 1992.
As well as monitoring species levels, it suggests ways to protect them, such as new legislation and physical habitat improvements.
The 1994 report listed 577 species at risk.
A spokeswoman for the Department for Environment, Food and Rural Affairs (DEFRA) said the list would now go before ministers for consideration.
"When finalised we hope it will provide a springboard for protecting threatened species for at least the next decade," she said.