Date of this Version
Published in Agriculture, Ecosystems and Environment 268 (2018), pp 162–170.
Although both managed and unmanaged bees are important pollinators of crops and wild plants, efforts to address questions about landscapes that best support pollinators often focus on either wild pollinators or honey bees. This study examined if there was concordance between the success of wild bee communities and managed honey bee colonies at sites varying in floral availability and disturbance level in a predominantly agricultural landscape. We also determined which agricultural land uses best supported wild bee communities. The study area in the state of North Dakota in Northern Great Plains in North America is home to understudied native bee communities as well as over ¼ of U.S. commercial honey bee colonies during the summer months. There is an assumption that honey bees can do well in agricultural areas but that wild bees need natural areas to thrive. We compared wild bee community success with health and survival of managed honey bees (data obtained from a related study) at six apiary locations over three years. We examined wild bee communities and surrounding land uses at 18 locations, three of which were spatially associated with each of six apiary locations. Wild bee abundance and species diversity were positively correlated with honey production, a measure of honey bee success, indicating that locations supporting successful honey bee colonies also supported successful wild bee communities. Grasslands, bee-forage crops, wooded areas, and wetlands were associated with increased abundance, species diversity, or functional diversity of wild bee communities. Crops not providing forage for bees, predominantly soybean, corn, and wheat, were associated with decreased functional diversity, decreased aboveground nesting bees and bees with shorter active season durations, and decreased honey bee survival. Pollinator conservation efforts retaining and enhancing grasslands, wooded areas, wetlands, and crops providing bee forage will likely support the growth, reproduction, and survival of diverse wild bee communities and the success of managed honey bees in areas dominated by intensive agriculture.
Includes supplemental materials.