Biofuel crops might bee harming pollinators, study says

Increasing biofuels production in the US could be posing a threat to the country’s already troubled bee population, a new study finds.

The Northern Great Plains of North and South Dakota, which support over 40%of US commercial honey bee colonies, are quickly becoming less conducive to commercial beekeeping as a result of land use changes, according to a US Geological Survey (USGS) study.

The USGS scientists found that landscape features favoured by beekeepers for honey bee colony – or apiary – locations are decreasing in the region, and crops actively avoided by beekeepers, such as corn and soybeans, are becoming more common in areas with higher apiary density.

Areas that showed high levels of grassland loss and high apiary density were mostly in central and southern North Dakota and the eastern half of South Dakota.

The study was published in the journal Proceedings of the National Academy of Sciences.

“Insect pollinators are critically important for maintaining global food production and ecosystem health, and US insect pollination services have an estimated annual value of $15 billion (€13.4bn),” said Clint Otto, a scientist at the USGS Northern Prairie Wildlife Research Center and the lead author of the report.

The scientists investigated changes in biofuel crop production, including corn and soybeans, and grassland cover surrounding approximately 18,000 registered commercial apiaries in the Dakotas from 2006-2014.

Results show a continual increase in biofuel crops, totalling 1.2 million hectares or almost 3 million acres, around apiaries mainly located in the Prairie Pothole Region of the Dakotas.

These crops were avoided by commercial beekeepers when selecting apiary sites in the region.

The conversion of pasture, conservation grasslands, and bee-friendly cultivated crops to biofuel crops likely impact both managed and wild pollinators, because it reduces forage availability and increases the use of chemicals that negatively affect pollinators and their ecosystem services.

“Our study identifies areas within the Northern Great Plains that managers can target for honey bee habitat conservation,” Otto said. 

The scientist underline the research’ importance as one of the key goals of the Pollinator Health Task Force strategy is to establish 7 million acres of pollinator habitat by 2020.

Most of the commercial honey bee colonies that spend the summer in the Dakotas provide pollination services for crops such as almonds, melons, apples, and cherries elsewhere in the US.

According to the study, the Northern Great Plains have served as an unofficial refuge for commercial beekeepers because of their abundance of uncultivated pasture and rangelands, and cultivated agricultural crops such as alfalfa, sunflower, and canola that provided forage for bees.