The planning system is failing to protect England's wildlife and natural areas, many of which are facing major declines, a report has warned.
Developers should be required to ensure large construction projects deliver more benefits for wildlife than the harm caused by building on or near important natural sites, the study by the think tank Policy Exchange said.
Well-loved species such as hedgehogs and house sparrows have seen numbers halve in the past 25 years, while farmland bird numbers have fallen by four-fifths since the 1960s and three-quarters of butterfly species are in decline.
And 11 of the UK's 15 important types of habitats are declining, the report warned.
Some of England's land is highly protected, but this has led to "ghettoisation" of habitats, which are now isolated and fragmented, while high-value areas which do not have protection have been lost to intensive agriculture and development.
Under planning regulations, large developments should deliver an overall net gain for biodiversity "wherever possible", but the report warned the vague language meant the rules were being applied haphazardly.
A Freedom of Information request by Policy Exchange revealed that two-fifths (41%) of England's 354 local planning authorities were able to provide evidence that they had ensured developers compensated for damage to important habitats.
And when compensation measures were carried out, by providing new high-quality wild spaces to replace those that were lost, the sites were not properly monitored in almost three-quarters (74%) of cases.
The new sites were not making up for the land that was lost, with 0.58 hectares (1.4 acres) of new green space provided for every one hectare (2.5 acres) lost. In the US, projects must deliver a 29% increase in good land for wildlife.
Policy Exchange said the new guidelines on planning - the controversial National Planning Policy Framework (NPPF) - should state that all large developments must deliver an overall net gain for wildlife and habitats.
The Environment Department is conducting a pilot "offsetting" scheme, in which developers would pay wildlife charities or farmers to create new areas managed for conservation to make up for land that has been lost to construction schemes.
But the report calls for the pilot to be made compulsory, despite concerns over costs, in order to encourage organisations and farmers to invest in drawing up projects and to highlight how much developers should be paying for losses to wildlife.
It also suggests that a national compulsory offsetting scheme would add around £70 million to the cost of development, 0.1% of the total annual value of new construction, which would help to meet the shortfall in funding for nature.
Environmental impact assessments of the effects on nature of development, which are carried out by the developer and are often inconsistent and poor quality, should instead be commissioned by local authorities, the study urges.
This would ensure the value of nature on sites is properly assessed, which would encourage development to take place on lower value land.
Guy Newey, author of the report, said: "A failure to properly value biodiversity has led to the decline of many once-common species and the disappearance of important habitats over the past 60 years.
"However, sensible policy steps can encourage development while, at the same time, improving our natural environment.
"It is crucial that biodiversity protection is part of the decision on how we use land, rather than ignored, as is often the case now."
The Policy Exchange report also said EU subsidies paid to farmers to carry out conservation measures on their land had made some improvements to England's countryside.
But "auctions" where landowners can bid to provide protection for a share of a pot of money could be a more efficient way of spending subsidies, for example because it would allow neighbours to club together to run more complex and valuable projects.
Reform of the EU subsidy system is under way, and the report warns plans to require all farmers across the bloc to undertake the same environmental measures to get their payments were "clumsy" and would not deliver cost-effective benefits for wildlife.
A Department for Communities and Local Government spokesman said: "Planning reforms reinforce powerful environmental safeguards and put communities at the heart of deciding where development should go.
"They recognise the intrinsic value and beauty of the countryside, whether or not it is specifically designated, and allow communities to safeguard their natural and historic environment.
"Our wildlife sites and species are vitally important and we recently undertook a review of the implementation of the Habitats Directive to ensure that it was enabling the sustainable development of key infrastructure while maintaining a high level of environmental protection.
"Biodiversity offsetting could be another way of ensuring that business and wildlife can continue to co-exist. We are currently undertaking research into the impact of biodiversity offsetting in a number of pilot areas and will publish the results in due course."
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