Industrial agriculture’s growing dependence on single, pollinator-dependent crops is jeopardising global food security and economic stability, according to a large multinational study.
The research, published in the journal Global Change Biology, is based on 50 years of global and regional data from the UN Food and Agriculture Organisation.
Results show that while the world’s total agricultural area increased by 40.6% over that period, land covered by crops reliant on pollination from bees and other insects grew by a massive 137%.
Despite this, crop diversity only increased by 20.5% overall, and even declined in some places.
The researchers did not expect to find this trend, says study lead Marcelo Aizen, from the National Council for Scientific and Technological Research (CONICET) in Argentina.
They had hypothesised that because 85% of dominant crops depend to varying degrees on animal pollinators for high yield, their expansion over the past five decades could have resulted in more crop diversification.
Drivers of the problem include rapidly expanding industrial farming of oilseed crops such as soybean, canola and oil palm in South America, Africa and Asia, to meet market demand.
Soy production, for instance, has increased by about 30% per decade globally, says Aizen. “This is problematic because numerous natural and semi-natural habitats, including tropical and subtropical forests and meadows, have been destroyed for soy fields.”
Because these pollinator-dependent crops are farmed over large areas as monocultures, a two-fold problem arises: reduced pollinators alongside increased demand. The resulting low yields lead to further land-clearing to extend the harvests.
Crop diversity provides a stable food source for pollinators all year round. But if only one or two crops are grown, the available pollen is limited to certain times of the year.
Added to this, monocultures impact biodiversity, habitats and natural pest control, increasing reliance on pesticides and herbicides. These factors all impact the survival of pollinators, which are declining worldwide.
“Just a few months ago, the World Biodiversity Council, IPBES, revealed to the world that up to one million animal and plant species are being threatened with extinction, including many pollinators,” says co-author Robert Paxton, from Martin Luther University in Germany.
This includes an alarming decline in wild bees: essential pollinators that face threat of extinction if urgent action is not taken.
Declining crop diversification is most worrying in this regard.
“Habitat homogenisation due to, for instance, monoculture expansion could be one of the most important drivers affecting bee abundance and diversity,” the authors write.
In turn, pollinator-reliant single crops impact a nation’s economic and food security.
Poorer areas will be most affected. But the impacts of crop failure would be felt worldwide, as developing nations grow them for affluent countries.
“If, for example, the avocado harvest in South America fails, people in Germany and other industrial nations may no longer be able to buy them,” says co-author Robert Paxton, from the German Centre for Integrative Biodiversity Research.
Taking all this into account, the results are an “alarm call” for agriculture to use more ecological and pollinator-friendly practices, according to the paper.
Improving bee habitats is a key solution, says Aizen. Among other strategies, this can be achieved by cultivating more diverse crops on a single piece of land and rotating them.
Other recommendations include intercropping with native flowers and hedgerows and restoring natural areas next to crops.
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Natalie Parletta is a freelance science writer based in Adelaide and an adjunct senior research fellow with the University of South Australia.
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