THEY have become a familiar - and often misunderstood - feature of the Worcestershire countryside for more than a decade, but now the county's areas of set-aside land could disappear, thanks to the EU.

Often in the form of wide headlands around the edges of arable fields or sometimes whole fields left to grass over, set-aside was first introduced in the early 1990s as a way of dealing with over production of cereals.

Landowners were compensated for not planting all their available land, thereby reducing the total cereal production.

This led to uninformed criticisms of farmers being paid "for doing nothing". But a beneficial effect of the legislation was the creation of thousands of new nature reserves', where flora and fauna flourished on newly set-aside land.

Now, Worcestershire Wildlife Trust is concerned this wildlife could suffer as a result of plans to remove the set-aside requirement for agricultural land. Under current legislation, a percentage of a farm's land must be left fallow or set-aside. Current EU set-aside targets stand at eight per cent.

However, in response to rising food prices, a zero per cent set-aside target has been proposed, from October this year, by the EU commissioner for agriculture, Mariann Fischer-Boel. The Department for Food, Environment and Rural Affairs (Defra) is currently considering whether any mitigating environmental requirements might need to be introduced, in the short term, if the European Commission's proposed zero per cent level of set-aside is agreed for 2008. Nationally, the wildlife trusts are pressing Defra to determine this with some urgency.

Both conservationists and landowners recognise the set-aside system has delivered many environmental benefits. If fully implemented the zero per cent proposal could result in up to 400,000 hectares of set-aside being removed from the countryside. Included in this figure are more than 100,000 hectares of field margins, buffer zones and small fields - vital refuges for wildlife.

Caroline Corsie, Worcestershire Wildlife Trust's farms and agriculture officer, explained: "Worcestershire Wildlife Trust farms at Lower Smite Farm, near Hindlip and Hill Court Farm, Longdon, near Tewksbury, show that fallow field margins and set-aside land become wildlife havens supporting increasing populations of small mammals, butterflies, crickets, many other insects and farmland birds. If the European proposals are introduced with no provision or mitigation for wildlife, the potential loss of set-aside land from Worcestershire's agricultural landscape will be a worrying step backwards for wildlife conservation and biodiversity in the county."

Studies have shown set-aside land has become an important habitat for endangered birds and insects, allowing farmland birds such as skylarks, whose numbers have been in steep decline, to benefit from the supplies of wild seed found there.

The natural regeneration of wild plants in spring and early summer also provides an ideal habitat and food sources for a wide range of wildlife including many birds, mammals like brown hares and field mice and insects such as bumblebees, plus the reduced use of fertilisers and pesticide on set-aside has benefits for wildlife while improving water quality by reducing diffuse pollution.

Under set-aside, fallow areas can provide connectivity corridors for species across large areas of land, mitigating the effect of climate change as wildlife is forced to adapt and move.

John Cousins, the wildlife trusts' head of agricultural policy, said: "The overnight loss of hundreds of thousands of hectares of set-aside could have serious consequences for wildlife. These plans jeopardise commitments from the European Union to halting biodiversity loss by 2010.

"Farmers have done a fantastic job benefiting the environment through management of set-aside land. We need to continue to provide environmental fallow areas such as buffer zones and six-metre field margins as vital habitat for endangered wildlife. We want to work together with Defra and farmers to help find mechanisms to keep the biodiversity benefits accrued through set-aside.

"If set-aside is to be phased out under the Common Agricultural Policy it must be done so gradually. We must ensure that gains for farmland biodiversity are not lost while taking into account the need to provide realistic support for farmers to deliver such environmental benefits. The trusts believe this can be achieved through modification to existing measures."