Biodiversity-food trade-offs when agricultural land is spared from production

Biodiversity conservation in agricultural landscapes, the world's predominant land use, could involve sparing, or setting aside, agricultural land from production, implying biodiversity–food trade‐offs. Employing bird species and agricultural data in two panel data sets, we evaluate the extent of set‐aside's trade‐offs in England between 1992 and 2007. Mixed biodiversity outcomes are reflected in a marginal effect, of a 100 ha increase in set‐aside, associated with a 1%–2% increase in species abundance and richness, no impact on Shannon‐Wiener diversity, and a 0.03 standard deviation fall in phylogenetic diversity. Lower phylogenetic diversity indicates that populations of less genetically distinct bird species appear when set‐aside increases. These effects are discontinuous for abundance and richness, and larger in the long run than in the short run for richness and phylogenetic diversity. Set‐aside led, on average, to a 7%–9% fall in cereal land. In turn, this led to an up to 2% decline in cereal output. A yield increase of 5%–10% is likely due to the setting aside of mostly marginal land. Biodiversity–food trade‐offs in agricultural landscapes could be minimized with a carefully targeted set‐aside policy, based on clearly defined biodiversity goals, and in settings where there is still scope for intensification.