Alexandra M. Klein, Georg-August University, Bernard E. Vaissičre, Institut National de la Recherche Agronomique, James H. Cane, USDA-ARS, Ingolf Steffan-Dewenter, Göttingen University, Saul Cunningham, CSIRO, Claire Kremen, University of Berkeley, and Teja Tscharntke, Georg August University.
The extent of our reliance on animal pollination for world crop production for human food has not been previously evaluated and previous estimates for countries or continents have seldom used primary data. In this review, we expand previous estimates using novel, primary data from 200 countries and found that fruit, vegetable or seed production from 87 of the leading global food crops is dependent upon animal pollination, while 28 crops do not rely upon animal pollination. Global production volumes give a contrasting perspective, however, since 60% of global production comes from crops that do not depend on animal pollination, 35% from crops that depend on pollinators, and 5% are unevaluated. Using all crops traded on the world market and setting aside crops that are solely passively self-pollinated, wind-pollinated or parthenocarpic, we then evaluated the level of dependence on animal-mediated pollination for crops that are directly consumed by humans. We found that pollinators are essential for 13, production is greatly pollinator-dependent for 30, moderately 27, slightly 21, unimportant for 7, and are of unknown significance for the remaining 9.
We further evaluated whether local and landscape-wide managing for natural pollination services could help to sustain crop diversity and production. Case studies for nine crops on four continents revealed that agricultural intensification jeopardizes wild bee communities and their stabilizing effect to pollination services at the landscape scale.