Comparing organic farming and land sparing: optimizing yield and butterfly populations at a landscape scale
J. A. Hodgson1*, W. E. Kunin1, C. D. Thomas2, T. G. Benton1 and D. Gabriel1
Organic farming aims to be wildlife-friendly, but it may not benefit wildlife overall if much greater areas are needed to produce a given quantity of food.
We measured the density and species richness of butterflies on organic farms, conventional farms and grassland nature reserves in 16 landscapes. Organic farms supported a higher density of butterflies than conventional farms, but a lower density than reserves.
Using our data, we predict the optimal land-use strategy to maintain yield whilst maximizing butterfly abundance under different scenarios. Farming conventionally and sparing land as nature reserves is better for butterflies when the organic yield per hectare falls below 87% of conventional yield. However, if the spared land is simply extra field margins, organic farming is optimal whenever organic yields are over 35% of conventional yields. The optimal balance of land sparing and wildlife-friendly farming to maintain production and biodiversity will differ between landscapes.
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Ecology Letters (2010) 13: 1358-1367
Author Locations and Affiliations
(1) Institute of Integrative & Comparative Biology, LC Miall Building, University of Leeds, Leeds LS2 9JT, UK
(2) Department of Biology Area 18, Wentworth Way, University of York, York, YO10 5DD, UK
* Corresponding author, E-mail firstname.lastname@example.org
Posted September 2010