The 2011 State of Britain's Mammals study says the species are still under threat despite efforts to protect them.
But it says conservation schemes have benefited otters, polecats and water voles and half of the monitored species have stable or rising populations.
Animal charity the People's Trust for Endangered Species commissioned the report from Oxford University.
It provides an overview of research by wildlife and conservation experts across the UK.
Researchers from the university's Wildlife Conservation Research Unit (WildCRU) found the hedgehog population had dropped from some 30 million in the 1950s to 1.5 million.
Report author Professor David Macdonald said the impact of agricultural management and environmental schemes on hedgehogs would be monitored over the next few years and used to influence agri-environment schemes.http://www.blogger.com/img/blank.gif
The report found that red squirrels were almost extinct in England.
"We expect the future of red squirrels to be confined to a few islands, such as Anglesey and the Isle of Wight, or in the Highlands of Scotland," Prof Macdonald said.
He expressed the benefits of land being taken out of agricultural use and allowed to grow wild and called for the reintroduction of extinct species such as the beaver. Beavers have been brought back in a trial scheme in Scotland.
Republished with acknowledgements to BBC News.
