Agroforestry Systems Enhance Farmland Biodiversity and Ecosystem Services in Subtropical Agricultural Landscapes

Abstract:

Subtropical agricultural landscapes are facing severe biodiversity loss and degradation of ecosystem services due to intensive monoculture. Agroforestry systems (AFS), which integrate trees with crops and/or livestock, have been proposed as a sustainable alternative to monoculture. This study evaluated the effects of three typical AFS (alley cropping, silvopasture, and forest garden) on farmland biodiversity (plant, insect, and soil microbial diversity), key ecosystem services (pollination, pest control, soil carbon sequestration, and water regulation), and crop yield in subtropical agricultural landscapes across four countries (Brazil, India, China, and Spain). Results showed that compared to monoculture, AFS significantly increased plant species richness by 47%, insect species richness by 38%, and soil microbial biomass carbon by 34%. AFS also enhanced pollination service (29% higher pollinator visitation rate), pest control service (35% lower pest abundance), soil carbon sequestration (31% higher soil organic carbon content), and water regulation (26% higher soil water-holding capacity). Additionally, AFS improved crop yield by 12% and yield stability by 23%. Structural equation modeling revealed that AFS indirectly improved crop yield through enhancing biodiversity and ecosystem services. These findings demonstrate the potential of AFS to mitigate biodiversity loss and enhance the sustainability of subtropical agricultural landscapes.