Endangered heathland species in England could become extinct because of the poor condition of their habitat, conservationists have warned.
Natural England says wildlife, such as the stone curlew, nightjar and sand lizard, could disappear if lowland heathland is not protected.
It found all of the 104 sites surveyed were in poor condition, even those which were in conservation schemes.
Heathland is currently a priority for the UK Biodiversity Action Plan.
Until about 100 years ago, heathland was a valuable resource for local communities. Trees were felled for fuel, animals grazed the land and the wildlife that favoured such open areas flourished.
Now, due to the expansion of urban areas and arable land, only 60,000 hectares (148,263 acres) remain covered by lowland heathland in England.
But even these do not meet the standards set for protected Sites of Special Scientific Interest, the latest survey for Natural England, the RSPB, the Joint Nature Conservation Committee and the Department for Environment, Food and Rural Affairs has found.
Sir Martin Doughty, chairman of Natural England, said such habitats needed to be protected to ensure the plant and animal species they support were "not lost forever".
"There is clear evidence that many of the larger heathlands - such as the Devil's Punch Bowl in Surrey and the East Lizard peninsula - managed for conservation and recreation are in better condition.
"To help restore other sites to these high standards we must ensure that they are properly targeted through stewardship schemes to secure appropriate management."
Birds such as the stone curlew and stonechat, which require bare ground, short heather and grasses, the Dartford warbler, which needs gorse and short vegetation, and the nightjar, which nests in open habitat, are in danger, the report warns.
Sand lizards, which only live on heathland and sandy areas and have disappeared from much of the UK, and plants, such as the marsh gentians and marsh clubmoss, are also under threat, it adds.
Lowland heathland is one of a number of habitats being prioritised under the UK Biodiversity Action Plan, 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.