A Western honey bee on a honeycomb. Credit: Matthew T Rader, MatthewTRader.com, CC-BY-SA
Key points:
- Honey yields in the U.S. have been declining since the 1990s.
- A new study shows herbicide application, land use and weather anomalies are to blame.
- The researchers stress the importance of identifying regions and landscapes with enough flowers to make them bee-friendly.
Honey yields in the U.S. have been declining since the 1990s. Now, a new study by Penn State researchers has uncovered clues in the mystery of the missing honey.
Using five decades of data from across the U.S., researchers analyzed the potential factors and mechanisms that might be affecting the number of flowers growing in different regions—and, by extension, the amount of honey produced by honey bees.
The study, recently published in Environmental Research, found that changes in honey yields over time were connected to herbicide application and land use, such as fewer land conservation programs that support pollinators. Annual weather anomalies also contributed to changes in yields.
Overall, researchers found that climate conditions and soil productivity—the ability of soil to support crops based on its physical, chemical and biological properties—were some of the most important factors in estimating honey yields. States in both warm and cool regions produced higher honey yields when they had productive soils.
The study results show that the eco-regional soil and climate conditions set the baseline levels of honey production, while changes in land use, herbicide use and weather influenced how much is produced in a given year.
While scientists previously knew that many factors influence flowering plant abundance and flower production, prior studies were conducted in only one region of the U.S.
One of the biggest stressors to pollinators is a lack of flowers to provide enough pollen and nectar for food. Because different regions can support different flowering plants depending on climate and soil characteristics, the researchers stress the importance of identifying regions and landscapes with enough flowers to make them bee-friendly.
“What’s really unique about this study is that we were able to take advantage of 50 years of data from across the continental U.S.,” said co-author of the paper Christina Grozinger, professor of entomology and director of the Center for Pollinator Research. “This allowed us to really investigate the role of soil, eco-regional climate conditions, annual weather variation, land use and land management practices on the availability of nectar for honey bees and other pollinators.”