Are there differences in the diversity of bees between organic and conventional agroecosystems in the Pampa biome?

Insect pollination is essential for the maintenance of ecosystems and for agricultural productivity. Bees are the main pollinator group and their assemblages are threatened by agricultural intensification. This study aimed to compare the diversity and structuring of bee assemblages between organic and conventional agroecosystems and to evaluate the influence of landscape composition on bee abundance in the Pampa biome. The study was carried out on three organic and three conventional family farms. Sampling was performed during the summer using pan traps. Four sampling units were placed on each farm, of which three were placed in crop field areas and one in native forest remnants. The diversity profile showed no significant difference between agroecosystems. Species abundance distribution indicates fewer dominant species in the organic system, suggesting the positive influence of polyculture on assemblage structure. Bee composition was different between agroecosystems. Notably, the species composition of bees in the forest edge of conventional farms was quite similar to that found in the organic habitats, indicating the importance of forested environments as a refuge for bees in conventional systems. The landscape analysis showed that the increase in the proportion of crop field areas negatively influenced the abundance of bees. We suggest that the maintenance of a heterogeneous agricultural landscape and smallholdings, composed of native and semi-natural habitats and organic practices on family farms can help to provide diverse niches for wild bees in the Pampa, contributing to biodiversity conservation and supporting ecosystem processes, like pollination.

Automated summary

This study compared the diversity and structuring of bee assemblages between organic and conventional agroecosystems and evaluated the influence of landscape composition on bee abundance. The results showed higher species richness in the organic system with different species composition. The species composition of bees in forest edges of conventional farms was similar to organic habitats, indicating the importance of forested environments as a refuge for bees in conventional systems. The increase in the proportion of crop field areas negatively influenced the abundance of bees.