Hedgehogs and house sparrows have been included on an updated list of species and habitats which need protection.
Tidier gardens and urbanisation are blamed for hedgehogs' decline
The new Biodiversity Action Plan (BAP) has identified 1,149 species and 65 habitats in the UK as being in need of conservation and greater protection.
When the action plan was launched in 1997, it listed 577 species - half the number included in the updated version.
Wildlife experts said this was a result of wider research and not necessarily down to more habitat being destroyed.
Other animals added to the list for the first time include the grass snake and the garden tiger moth; while otters, bottlenose dolphins and red squirrels are deemed to remain in need of habitat protection.
BAP PRIORITY SPECIES
Birds - 59 species
Fish (freshwater) - 14 species
Reptiles/amphibians (herptiles) - 10 species
Lower plants and fungi - 337 species
Marine fauna and flora - 88 species
Invertebrates - 411 species
Terrestrial mammals - 18 species
Vascular plants - 212 species
(Source: UK Biodiversity Action Plan 2007)
But the latest BAP shows that a number of species have benefited from being featured on the original list 10 years ago. The numbers of ladybird spiders and lady's slipper orchids are at a 50-year high.
The BAP is considered to be one of the most authoritative reference sources for the state of the UK's wildlife.
The result of more than two years of research by more than 500 wildlife experts and a large number of volunteers, it brings together key scientific data on all the listed species in one document.
As well as outlining the state of British species, it also contributes to global conservation commitments, outlined in the UN's Convention on Biological Diversity (CBD).
Biodiversity Minister Joan Ruddock said the updated action plan would help shape the government's conservation policy.
"Conserving biodiversity is essential if we are to pass on a healthy environment to the next generation," Ms Ruddock said.
"The new list will help us target our resources and efforts where they are needed, and demonstrates our commitment to publish new priorities, targets and plans for halting biodiversity loss by 2010."
'Cause for alarm'
The Royal Society for the Protection of Birds (RSPB) said that as well as the house sparrow, the starling was another familiar garden bird to feature on the BAP list of 59 bird species.
"The fact that the bird list now includes more than a fifth of all the UK's regularly occurring birds is a cause for alarm, " said Mark Avery, the RSPB's conservation director.
House sparrows are one of the new additions to the action plan
"We will have to act fast if we are to meet obligations of halting the loss of biodiversity by 2010."
But Dr Avery added that the BAP had focused efforts on stemming the decline in a number of vulnerable species.
"To its credit, we have seen dramatic increases in key species, like bittern, stone-curlew, corncrake, nightjar, cirl bunting and woodlark."
A separate study, also published on Tuesday, also highlighted the decline in the UK's hedgehog population.
The study by the University of London for the People's Trust for Endangered Species and the British Hedgehog Preservation Society listed tidier gardens and urbanisation as key factors affecting the fall in the number of the small mammals.
Nigel Bourne, chairman of the Wildlife and Countryside Link's biodiversity working group, welcomed the updated list and called it a "major boost".
"The list will focus efforts on the real, shared conservation priorities in the UK.
"The conservation charities that make up Link... look forward to continuing to work in partnership with the government," Dr Bourne added.
"Together we can turn the list into targeted action to deliver the conservation of our very special habitats and species."