Migratory beekeeping impacts native bee species in China
Native pollinators play a critical role in ecosystems across the world for stability of forests and grasslands, and agricultural productivity. A global decline in pollinator populations, which can be attributed to a number of human-caused ecological disturbances puts their ecosystem services at risk. This recent study in China indicates that in particular situations, beekeeping poses a disturbance that changes the habitat and impacts the population dynamics of native bee species.
Due to the demand for pollination services, large commercial beekeeping operations are used in agricultural areas that don’t have sufficient native pollinators. In many areas of the world including North America, the Western honeybee is an introduced species. Between pollination contracts, beekeeping operations move hives into non-agricultural areas that are rich in floral resources to build colony strength. However, the impact that apiaries have on native pollinators and ecosystems in these areas is a concern.
Anthony Vaudo, biological scientist at the Rocky Mountain Research Station, and his team of researchers carried out a study in the open meadows of the Qinghai-Tibet Plateau in China. This was a unique location to study the impact of honeybee apiaries on native pollinators because it was independent of other ecological disturbances such as pesticide use or reduced floral resources. They were also able to study the short-term effects of small-scale honeybee introduction at new hive locations at present, as well as the long-term impacts on sites that had previously contained hives but no longer did because of local ordinance.
Vaudo and his team found that that low-density, migratory beekeeping in this ecosystem presents an intermediate ecological disturbance. In areas with current hives, the abundance of native bee species is reduced, but rebounded a year after the hives were removed. However, there were lasting changes to the community composition. The greatest difference was found in the abundance of the most dominant native bee species. Both present and previous sites had much lower abundance of this species than sites that never had apiaries. These results indicate that the presence of honeybees decreased the abundance of the dominant native species and potentially allowed other bee species to occupy limited nesting or foraging sites. This restructured the native bee community composition and led to an increase in phylogenetic diversity.
The team emphasizes that these results should be interpreted in context: the ability for native bee species to recover their population numbers at these sites is likely dependent on a number of factors, including that the environment was vast and full of wildflowers, free of other stressors and disturbances, and beekeeping was at low-density. Therefore, these results cannot be generalized to other environments or ecosystems where large scale beekeeping practices are operating but represent the isolated impact of apiaries on native bee species. This study is helping scientists and practitioners build the body of knowledge necessary to decide the best path forward for commercial beekeeping, one that maintains the integrity of native pollinator communities while still meeting agricultural needs.