Wild bees in the U.S. are declining across vast swathes of the country, especially in those regions used for growing corn destined for biofuel, according to a new investigation. The study is the first to look at the status of wild bees in the United States, and how their decline could affect farmers who depend on them for pollination. While the researchers weren’t able to pin down an exact cause for the decline, they are fairly certain that an intensification of agriculture plays a major role.
Between 2008 and 2013, the study found that wild bees declined across 23 percent of the country, and that these losses were associated with the conversion of wild habitat into intensive agriculture to feed the biofuel industry. The U.S. is the largest producer of biofuel in the world, as 40 percent of all corn grown in the nation goes into its production, so the fact that its manufacturing might be having an impact on such vital pollinators is a worrying finding. This then has knock-on effects for other crops, such as those used directly as food, which are also dependent on the bees' survival.
“We see striking mismatches in many places between the demand for pollination and the ability of wild pollinators to support that need,” explains Neal Williams, who coauthored the study published in the Proceedings of the National Academy of Science. “Indeed, it is crops where demand has most increased that we estimate greatest decline in wild pollinator supply.”
The researchers found that around 39 percent of pollinator-dependent crops in the U.S. had lower than expected numbers of wild bees. Many claim that because the numbers of managed honeybee colonies (which are just one species of bee pollinator) are on the up as farmers intervene to artificially bolster the number of bees, we, therefore, have nothing to worry about. Despite the fact that increasing the number of honeybee colonies is simply treating the symptoms and not the cause, the study also found that this increase has been insufficient to keep up with the demand for pollinators as the populations of their wild counterparts are crashing, as despite having more honeybees, the pollination-demand of crops still outstrips the supply.
With wild bees contributing an estimated $3 billion in ecosystem services through the pollination of crops, as their numbers decline it could lead to an increase in production costs for farmers, and could eventually destabilize the entire crop production in some regions. The new study comes as a result of the memorandum issued by Obama in 2014 to assess the country's pollinators and gain a better understanding of the situation they face.
While in Europe there has been much focus on how pesticides, such as neonicotinoids, are harming pollinators, the researchers were not able to confirm such a link in this study. They have, however, noted that the regions that have seen the largest decline in wild bee numbers are also those that have the most intense agriculture, and that that is probably not a coincidence. This could be a mixture of both the use of pesticides and habitat loss as wild areas are converted to farmland.
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