Modeling the suitability of landscapes for managed honeybees - a case study in the northern Great Plains

Bees provide a crucial ecosystem service in crop pollination. Maintaining healthy managed and wild bee populations is critical to continue this important service that also affects many crops and thus the food we eat. This study focuses on the ecosystem service provided by managed bees in the Prairie Pothole region of North Dakota, an area characterized by intensive agriculture and remnant grassland, wetlands, and prairies. A spatially explicit model was used to determine the suitability of the landscape for managed bees using floral resource quality estimates, foraging distances, and land use land cover data for 2008-2012. The model outputs are akin to a floral resource quality index for managed bees. This index was compared with honey production, which is being used as an indicator of managed bee health. The results show a strong positive relationship between honey production and the floral resource quality index in 2008, and a weaker positive relationship in 2009 and 2010. Results for 2012 were inconclusive. A linear mixed effect model was used to account for the sampling of the same locations over multiple years. The models were better than the null models and proved to be statistically significant, indicating the importance of land use land cover suitability for managed bees. The presumed factors contributing to the variability of the relationship between land use land cover and honey production between years are discussed. These include land use land cover changes, Colony Collapse Disorder, pesticide application, beekeeper intervention, and interannual weather variations.