By Mark Kinver
Science and nature reporter, BBC News
UK scientists say they have developed a system that can predict the future impacts of farming on an area's biodiversity.
Scientists hope farmers and wildlife will benefit from the "health check"
The "health check" is based on an assessment of how changes to farming methods can affect farmland birds' diet, foraging and nesting habits.
Existing eco-stewardship schemes are likely to result in key UK biodiversity targets being missed, researchers warn.
The University of Reading group's findings appear in the journal Science.
Researchers from the university's Centre for Agri-environmental Research said the system would help strike a balance between the need for increased agricultural production and environmental protection.
Focusing on farmland birds, the team developed a risk assessment framework that linked species' conservation status and population numbers with changes in agricultural methods.
The paper's lead author, Simon Butler, said: "We use farmland birds... because they are the focus of biodiversity conservation; and an index of the populations of farmland birds is one of the 15 headline indicators of sustainable development in the UK."
"Each species has a set of requirements it needs from the environment," he explained. "For birds, this can be broken down as needing somewhere to nest, somewhere to feed, and food availability.
"Our framework assumes that agricultural change will impact on the birds if any of the changes affect the quality or quantity of the birds' ecological requirements," Dr Butler added.
They then assessed how these requirements had been affected by "six key components of agricultural intensification" over the past 40 years.
These included switching from spring to autumn sowing, increased use of agro-chemicals, and increased land drainage.
Explaining the consequences, Dr Butler said: "Species that feed on a wider range of prey, and live in a greater number of habitats will be less vulnerable to the impact of agricultural change than species that have specialist requirements."
Using the framework, the scientists found that the introduction of genetically modified (GM) crops might have less of an impact on biodiversity than originally thought.
Referring to the UK farm-scale trials of herbicide-tolerant (GMHT) crops, Dr Butler said: "Research shows that two-thirds of the species in our list have ecological requirements that make them susceptible to the possible impacts associated with the introduction of GM crops.
"But if those crops are introduced into the current UK farming landscape, only one species is likely to be reclassified to a less favourable conservation status," he revealed.
The introduction of GM crops could be bad news for the meadow pipit
The bird that would suffer a decline was the meadow pipit, he said, prompting it to shift from the Amber List on the UK's Farmland Bird Index (FBI) to the Red List.
Another conclusion from the paper suggested that the UK's Entry-Level Stewardship (ELS) scheme for farmers, designed to mitigate the detrimental effects of agriculture, was unlikely to achieve its goal.
"Our research identified a disparity between the source of population decline and the focus of mitigation measures under the ELS," Dr Butler said.
"Our validation process shows that degradation within cropped habitat is the key driver for population decline, but ELS uptake data shows that the focus of current plans is on (field) margin and hedgerow management.
"Unless greater emphasis is placed on improving the value of cropped area habitat to biodiversity, progress towards reversing declines in farmland birds and meeting the government's target is unlikely," he warned.
Although not included in the Science paper, Dr Butler said that similar risk assessment frameworks had also been developed for mammals, insects and plants found on farmland.
The research is part of a wider programme that has been carried out over the past two years, involving scientists from Rothamsted Research and Reading, Oxford and Southampton universities.