Global agriculture shows limited evidence of a pollinator-driven yield decline to date
Marcelo A Aizen, Gabriela Gleiser, Carolina L Morales, Agustín Sáez, Lawrence D HarderAbstract
Background
During recent decades, declines in the abundance and diversity of wild pollinators have been widely documented, largely driven by human-induced disturbance, such as agricultural expansion, land-use change, pesticide use, invasive species, urbanization, and climate change. Because deficits in animal pollination often limit fruit and seed production in both wild plants and cultivated crops —due to insufficient or ineffective pollen deposition on flowers’ stigmas— pollinator decline has raised concern about consequences for plant reproduction and agricultural yields. Expected increases in pollination shortfalls are frequently portrayed as a global pollination crisis, with potential implications for food security.
Scope
We evaluate evidence of pollinator decline and its relevance within agroecosystems. We then examine whether pollen limitation is common among pollinator-dependent crops and assess whether its severity increases with crop reliance on pollinators. Finally, we revisit previous analyses and reanalyze long-term data from the Food and Agriculture Organization (FAO) to assess whether yield growth has slowed more markedly in crops with higher pollinator dependence.
Conclusions
Our review and reanalyses reveal limited evidence for the existence of a pollination crisis that is increasingly limiting the yield of pollinator-dependent crops globally. This conclusion stands despite robust evidence of a global decline in pollinator diversity, frequent pollen limitation—whose severity increases with crop pollinator dependence—and numerous demonstrations that reduced pollinator abundance and diversity constrain crop yields at local and regional scales. This apparent contradiction arises from various mitigating factors, including improved management of wild and domesticated pollinators, the spread of invasive bee species, and advances in crop breeding and cultivation, which have so far buffered global agricultural yields against the impacts of declining populations of native pollinators. Ultimately, deepening our understanding of the factors driving pollen limitation is crucial to ensuring that future crop yields can sustain the dietary needs of a growing global population.