Evaluating the significance of native vegetation surrounding orange orchards for the pollinator community

Abstract

Recognizing the importance of native vegetation close to agricultural fields in sustaining biodiversity and ecosystem services, this study aimed to evaluate the influence of native forests on the floral visitor’s community and provision of pollination services. We assessed floral visitor communities and conducted pollination-tests within orange orchards, in both Atlantic Forest and Cerrado biomes, in SP, Brazil. We selected four farms, with two experimental areas, with orange orchards adjacent to native vegetation. Floral visitors survey and pollination-tests were performed in five transects distant from the forest at: 0 m, 100 m, 200 m, 300 m, and 400 m. Floral visitors survey was performed by active collection. Pollination-tests were executed by three treatments: open pollination, pollinator exclusion and supplementary cross pollination. The experimental areas were mapped according to their coverage and land use and the Generalized Additive Models was employed to verify any correlation between the landscape metrics and the floral visitors. We recorded 3084 individuals from 30 taxonomic groups visiting orange flowers, with Apis mellifera L. being the most abundant species. While floral visitors’ richness showed no biome-specific differences, the abundance was higher in Cerrado. Species richness declined significantly with distance from forest edges, and abundance increased with greater landscape-scale forest cover. Despite demonstrating the critical role of forest remnants in maintaining biodiversity, we observed suboptimal fruit set likely attributable to anomalous climatic conditions rather than pollination deficits. These findings highlight the dual importance of local (proximity) and landscape (coverage) forest conservation for sustaining orchard pollinators, and the necessity of multi-year studies to disentangle climatic effects from true pollination service dynamics.