Pollinator shortage and global crop yield

Abstract

A pollinator decline caused by environmental degradation might be compromising the production of pollinator-dependent crops. In a recent article, we compared 45 year series (1961–2006) in yield, production, and cultivated area of pollinator-dependent and nondependent crop around the world. If pollinator shortage is occurring globally, we expected a lower annual growth rate in yield for pollinator-dependent than nondependent crops, but a higher growth in cultivated area to compensate the lower yield. We have found little evidence for the first “yield” prediction but strong evidence for the second “area” prediction. Here, we present an additional analysis to show that the first and second predictions are both supported for crops that vary in dependency levels from nondependent to moderate dependence (i.e. up to 65% average yield reduction without pollinators). However, those crops for which animal pollination is essential (i.e. 95% average yield reduction without pollinators) showed higher growth in yield and lower expansion in area than expected in a pollination shortage scenario. We propose that pollination management for highly pollinator-dependent crops, such us renting hives or hand pollination, might have compensated for pollinator limitation of yield.

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Acknowledgements

We thank Sofía Gonzalez for useful comments and suggestions. This work was conducted partly within the framework provided by the Restoring Pollination Services Working Group supported by the National Center for Ecological Analysis and Synthesis, a Center funded by NSF (grant no. DEB-0072909). We acknowledged additional funding by the Argentina National Council for Research (PIP 5066) and the National University of Comahue (B126/04). Lucas A. Garibaldi holds a fellowship from the Argentina National Council for Research and Marcelo A. Aizen is a career researcher of the same agency. Alexandra M. Klein is supported by the Alexander von Humboldt Foundation.

Figures and Tables

Figure 1 Mean ± 1 SE of the annual relative growth in yield and cultivated area for crops differing in their pollinator dependence. The lines are linear regressions without considering the 95% dependence group and taking each crop as a replicate. In parenthesis is the number of crops within each group.

Table 1 Annual growth in yield (β_Δyield) and cultivated area (β_Δarea) during 1961–2006 for highly pollinator-dependent crops (i.e., 95% average reduction in yield in the absence of pollinators) in the developed and developing world

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