Agroforestry transition increases insect diversity and reorganizes soil function in a Mediterranean orchard

Summary

Agricultural intensification has reduced biodiversity and weakened ecosystem functions essential for sustainable crop production. Agroforestry has been proposed as a regenerative strategy to restore these functions through vegetation diversification, yet its ecological effects at the farm scale remain insufficiently documented, particularly in Mediterranean perennial systems. Here, adaptive field monitoring and soil shotgun metagenomics were combined to investigate ecological responses across a 10 year agroforestry transition gradient in a Mediterranean citrus and olive farm. Mature agroforestry plots supported higher insect richness and functional diversity while maintaining stable pollinator communities. Plant insect interaction analyses suggested that potential pest activity was largely associated with spontaneous and supportive vegetation rather than crops. In contrast, soil communities showed limited changes in overall richness but substantial compositional and functional restructuring, including enrichment of the arbuscular mycorrhizal fungus Rhizophagus and proteins with nutrient cycling functions in advanced plots. Together, these findings suggest that agroforestry transition can promote functional diversification above and below ground and highlight the value of farmer led regenerative transitions coupled with integrative ecological monitoring for the development of more resilient agricultural systems.

Outcomes reported

Agricultural intensification has reduced biodiversity and weakened ecosystem functions essential for sustainable crop production. Agroforestry has been proposed as a regenerative strategy to restore these functions through vegetation diversification, yet its ecological effects at the farm scale remain insufficiently documented, particularly in Mediterranean perennial systems. Here, adaptive field monitoring and soil shotgun metagenomics were combined to investigate ecological responses across a 10 year agroforestry transition gradient in a Mediterranean citrus and olive farm. Mature agroforestry plots supported higher insect richness and functional diversity while maintaining stable pollinator communities. Plant insect interaction analyses suggested that potential pest activity was largely associated with spontaneous and supportive vegetation rather than crops. In contrast, soil communities showed limited changes in overall richness but substantial compositional and functional restructuring, including enrichment of the arbuscular mycorrhizal fungus Rhizophagus and proteins with nutrient cycling functions in advanced plots. Together, these findings suggest that agroforestry transition can promote functional diversification above and below ground and highlight the value of farmer led regenerative transitions coupled with integrative ecological monitoring for the development of more resilient agricultural systems.

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