Global agricultural productivity is threatened by increasing pollinator dependence without a parallel increase in crop diversification

AIZEN, MARCELO A.; AGUIAR, SEBASTIÁN; BIESMEIJER, JACOBUS C.; GARIBALDI, LUCAS A.; INOUYE, DAVID W.; JUNG, CHULEUI; MARTINS, DINO J.; MEDEL, RODRIGO; MORALES, CAROLINA L.; NGO, HIEN; PAUW, ANTON; PAXTON, ROBERT J.; SÁEZ, AGUSTÍN; SEYMOUR, COLLEEN L.

GLOBAL CHANGE BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 25 p. 3516 - 3527

1354-1013

The global increase in the proportion of land cultivated with pollinator‐dependentcrops implies increased reliance on pollination services. Yet agricultural practicesthemselves can profoundly affect pollinator supply and pollination. Extensive monoculturesare associated with a limited pollinator supply and reduced pollination,whereas agricultural diversification can enhance both. Therefore, areas where agriculturaldiversity has increased, or at least been maintained, may better sustain highand more stable productivity of pollinator‐dependent crops. Given that >80% of allcrops depend, to varying extents, on insect pollination, a global increase in agriculturalpollinator dependence over recent decades might have led to a concomitantincrease in agricultural diversification. We evaluated whether an increase in the area of pollinator‐dependent crops has indeed been associated with an increase in agriculturaldiversity, measured here as crop diversity, at the global, regional, and countryscales for the period 1961?2016. Globally, results show a relatively weak and deceleratingrise in agricultural diversity over time that was largely decoupled from the strongand continually increasing trend in agricultural dependency on pollinators. At regionaland country levels, there was no consistent relationship between temporal changesin pollinator dependence and crop diversification. Instead, our results show heterogeneousresponses in which increasing pollinator dependence for some countries andregions has been associated with either an increase or a decrease in agricultural diversity.Particularly worrisome is a rapid expansion of pollinator‐dependent oilseed cropsin several countries of the Americas and Asia that has resulted in a decrease in agriculturaldiversity. In these regions, reliance on pollinators is increasing, yet agriculturalpractices that undermine pollination services are expanding. Our analysis has therebyidentified world regions of particular concern where environmentally damaging practicesassociated with large‐scale, industrial agriculture threaten key ecosystem servicesthat underlie productivity, in addition to other benefits provided by biodiversity.