Mixed effects of honey bees on pollination function in the Tibetan alpine grasslands.

The global expansion of domesticated plant and animal species has profoundly impacted biodiversity and ecosystem functions. However, the spillover effect of non-native honey bees from mass-flowering crops into adjacent natural vegetation on pollination function within plant communities remains unclear. To address this, we conduct field experiments to investigate the ecological impacts of honey bees (Apis mellifera) and a mass-flowering crop (Brassica rapa var. oleifera) on pollinator communities, plant-pollinator interactions, and reproductive performance of wild plants in 48 pollinator-limited alpine grasslands. Our findings indicate that the transition of dominant pollinators from flies to honey bees enhances visitation fidelity of pollinator species and reconfigures pollination interactions due to an increase in competition between honey bees and native pollinator species. Additionally, honey bees increase, decrease or do not alter plant reproductive success, depending on the plant species. Here, we report the mixed effects of honey bees on pollination function in pollinator-limited alpine grasslands.