Exploring the effect of landscape composition and agroecological practices on wild bees in horticultural farms

Abstract

How farms and the surrounding landscape are managed locally substantially affects biodiversity, with consequent impacts on the supply of certain ecosystem services, such as pollination. Wild bees provide pollination services for small-scale horticultural farming, and are key to determining and improving farm production, as well as maintaining ecosystem-level diversity. Here, we investigated how landscape composition and agroecological practices affect wild bee community in small-scale horticultural farms. The study was conducted at 16 horticultural farms in the northern part of Madrid. The pan-trapping method was used to collect wild bees during the flowering period of horticultural plants. We interviewed farmers to identify which agroecological practices were primarily adopted to attain a resilient ecosystem. The most common practices adopted were weed control methods, natural fertilizer usage, pest control, and crop diversification. In total, 109 wild bee species were identified, and included individuals from all six bee families present on the Iberian Peninsula. One genus (Lasioglossum) was highly abundant, accounting for 68% of individuals, and is a known ground nester. Areas of sparse vegetation and bare soil and forested areas primarily enhanced the richness of bee species. On the other hand, abundance of wild bees is enhanced by pasture and forest areas. The presence of these habitats in areas surrounding farms might represent the potential nesting sites with important resources for wild bees. Small-scale horticulture production promotes landscape diversity, which strongly promotes the potential of different ecosystem services, including pollination and wild bees. Thus, implementing agroecological practices could transcend farms, and individual fields, to the landscape level, providing long-term sustainability of ecosystems.