On The Side

The European Union needs to rethink its abandonment of a policy that required farmers to let up to 15% of their land sit fallow for years at a time. That’s the conclusion of new review of the biodiversity benefits of the policy, which was abolished in 2008.

In 1988, EU officials began asking farmers to rest of some their fields, in large part to prevent crop surpluses that tended to drive down farm incomes. In 1993, the set-asides “became an obligation for any farmer receiving EU subsidies,” note Teja Tscharntke and Péter Batáry of Germany’s Georg-August University and Carsten F. Domann of the UFZ Centre for Environmental Research in the journal Agriculture, Ecosystems and Environment. Roughly 5% –15% of arable land was rotated out of production, with some farmers encouraged to seed the land with annual and perennial plants. “During this period, landscapes were often colorful, due to set-aside sowings,” the authors report.

The fallow land provided more than just pretty scenery, however: Studies found it also provided habitat for plants, insects and birds. As the grasslands aged, even small mammals benefited. The biodiversity benefits tended to be highest in “simple” landscapes with little ecosystem diversity.

The abolition of the set-aside scheme three years ago, however, “caused a sudden loss in habitat availability and biodiversity in agricultural landscapes.” The one exception is Switzerland, “where farmers are still obliged to set aside at least 7% of their farmland as ecological compensation.” Although researchers have done few studies to see how the shift has affected biodiversity, “there is little doubt about the generally negative effects,” the authors conclude.

Given the benefits of fallow land, it’s time to reverse course, they argue. “The demonstrated potential for conservation and ecosystem service benefits demands a revision of EU policy,” they conclude. And any new policy, they add, should reflect studies showing that setting aside about 20% of “seminatural noncrop habitat appears to be a rough threshold” for providing “sustaining services such as biodiversity conservation… as well as pollination and biological control.” – David Malakoff | February 13, 2011

Source: Tscharntke, T., Batáry, P., & Dormann, C. (2011). Set-aside management: How do succession, sowing patterns and landscape context affect biodiversity? Agriculture, Ecosystems & Environment DOI: 10.1016/j.agee.2010.11.025

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