Trophic cascades drive sustainability in the agricultural heritage rice-fish coculture system

Biodiversity-mediated trophic cascades are well established for plant diversity, but the role of biodiversity in the millennia-old Asian rice-fish agroecosystems has not been synthesized. We show in a meta-analysis of 113 studies worldwide that rice-fish coculture increases yields by 12.5%, while enhancing the abundance of invertebrate natural enemies (predators/parasitoids) by 99.3% and suppressing pest invertebrate herbivores (24.1%), disease (38.8%), and weeds (45.7%), compared with rice monoculture. These effects persist across organic and non-organic systems, as well as temperate and tropical zones. Biological pest control played a dominant role in enhancing crop production, with enemy-driven top-down effects suppressing herbivore populations. Four-year field experiments confirmed these patterns, demonstrating biological control and top-down effects. Behavioral assays further show fish preferentially target herbivores (e.g., planthoppers) while sparing predatory spiders, reinforcing trophic cascades. Our findings validate rice-fish coculture as a highly productive, sustainable agricultural system that enhances biodiversity, crop yields, and provides significant fish harvests for animal protein and additional farmer income. This approach aligns with the Food and Agriculture Organization (FAO) goals by harnessing biodiversity for ecological intensification and natural pest regulation, offering viable solutions for global food security and nutritional challenges.