The decline in the population of wild bees threatens crops in the US, where fields that need these insects are at risk of not being pollinated this year, according to a report published by the journal "Proceedings of the National Academy of Sciences ".
Of the fields dependent on pollination, 39% "will suffer the mismatch between the increase in demand for pollination and the fall in the number of wild bees," says the study, conducted by researchers at the University of Vermont.
Wild bees, according to the report, "are disappearing in several counties that include the main farmland of the country." Likewise, its population has decreased by 23% in the period between 2008 and 2013, and although there are bee farms bred to pollinate, they do not satisfy the demand.
In the short term, farmers will see increased production costs and, in the medium-long term, "US agricultural production may be destabilized," warns the report, which includes maps of the affected areas.
"This is the first spatial portrait of the state of pollinators and their impact in the US," explained Insu Koh, leader of the research team at the University of Vermont.
The map identifies the hotspots, spread over 139 counties across the United States, and dedicated especially to almond, blueberry, apple and pumpkin crops.
With this information, "government agencies and private organizations can focus their efforts" and support "a more sustainable agriculture and natural landscapes," said Rufus Isaacs, co-author of the study.
One of the main causes of the disappearance of wild bees is precisely the increase in cultivated fields, which means the destruction of their natural habitat.
Fields dependent on pollination by bees contribute more than $ 3 billion annually to the US economy, according to a presidential report released by the White House in June 2014.
US President Barack Obama requested, in that same report, a national estimate of the contribution of wild pollinators and their habitats, a call to which this study responds.