The team project that a combination of conventional farming and nature reserves would be better for butterflies if the organic yield per hectare falls below 87 per cent of conventional yield. But if the uncultivated land is not specifically managed for wildlife - being more like unmanaged field margins - organic farming would be better whenever organic yields rise above 35 per cent of conventional yields. The relative yield of organic farming is often somewhere between 35 per cent and 87 per cent of conventional yield, depending on the type of crop and landscape. The trade-off might also be different for other types of wildlife: for example wildflowers benefit more from organic farming than butterflies, and many birds do not benefit at all. The results suggest that organic farming will be better when organic yields are high and when spared land has low value to wildlife. Conventional farming will be better when organic yields are low and spared land is of high wildlife value.
Lead author, Dr Jenny Hodgson, of the Department of Biology at York, said: "This research raises questions about how agri-environment schemes and incentives could be improved. There could be much more scope for restoring and maintaining permanent, high-quality wildlife habitat. This might involve neighbouring farmers clubbing together to achieve a larger area of restored habitat, or setting up a partnership with a conservation organisation."
Author Prof Tim Benton highlights the fact that "More effective agri-environment methods will strengthen the case for conventional farming. The real challenge is to develop better ways to manage AES areas on conventional farms, so they can come closer to nature reserve standards. The spared land could be in nature reserves, but if properly managed, the spared land could also be in strips at the margins of fields."
One premise of this study was that we aim to maintain food yield and
|Contact: David Garner|
University of York