Impact of Pollinator Diversity on Crop Productivity

Abstract

The loss of pollinator diversity is a global food security threat, yet the relationship between pollinator functional diversity and crop yield stability remains unknown. We tested the impact of pollinator diversity on crop yields at 60 agricultural sites with three crops, apple, oilseed rape, and strawberry, using hierarchical linear mixed-effects models, functional traits, and economic risk analysis. We found that functional diversity (Rao's Q) is a better predictor of marketable yield than species diversity (R² of the best-fitting non-linear saturating model is 0.734 and RMSE 1.76 t·ha⁻¹). We found that functional diversity stabilizes yields over time (stability exponent γ = -0.59), with a 10% increase in functional diversity reducing yield instability by 5.9%. We found a threshold of semi-natural habitat (18.4% cover) below which pollination service decreases non-linearly. Trait analysis showed tongue length (14.7% primary effect) and flowering synchrony (12.2%) with crop flowering are the most important functional traits for yield. We calculate that losing 30% of pollinators would generate $9.16 billion in annual crop losses, and losing all pollinators would reduce crop yield by 38-51% and generate $38.7 billion in annual losses. We recommend that conservation strategies focus on maintaining functional diversity, not just species diversity, to maintain crop productivity and stability, and therefore, landscape restoration to above the 18.4% cover threshold is required to avoid major economic losses and food security.