Global diversity has declined as monocultures of crops including soybean, canola and palm take up more land than ever.
These crops only provide nutrition for pollinators during a very limited window when they are in bloom. This makes them an unstable source of food for insects, whose global numbers are already rapidly in decline. Heavy use of fertilisers has exacerbated this trend.
“Farmers are growing more crops that require pollination, such as fruits, nuts and oil seeds, because there’s an increasing demand for them and they have a higher market value,” said David Inouye at the University of Maryland and a co-author of the research paper.
“This study points out that these current trends are not great for pollinators, and countries that diversify their agricultural crops are going to benefit more than those that expand with only a limited subset of crops.”
Researchers analysed data from the United Nations’ Food and Agriculture Organisation (FAO) on the cultivation of field crops between 1961 and 2016. They found that fewer pollinators could mean that yields are much lower or even that harvests fail completely.
Agriculture is most unstable in Brazil, Argentina, Paraguay and Bolivia where expansion of soybean farms has driven deforestation. Soy is often exported to Europe as cattle feed.
“Soy production has risen by around 30 per cent per decade globally,” said Professor Marcelo Aizen of the National Council for Scientific and Technological Research (Conicet) in Argentina, who led the study.
“This is problematic because numerous natural and semi-natural habitats, including tropical and subtropical forests and meadows, have been destroyed for soy fields.”
Palm farming in Malaysia and Indonesia is having the same effect, according to the study published in Global Change Biology.
Although countries replacing forests with monocultures are most vulnerable, other countries are also becoming too dependent on pollinators.
In Europe, for example, farmland is getting smaller as urban development takes the place of agriculture. Pollinator-dependent crops are replacing non-pollinator-dependent crops such as rice and wheat.
This is causing problems in places like the UK, Germany, France, Austria, Denmark and Finland.
Although it is mainly poorer regions that are most at risk the consequences of crop failure would be felt worldwide.
“This work should sound an alarm for policymakers who need to think about how they are going to protect and foster pollinator populations that can support the growing need for the services they provide to crops that require pollination,” said Professor Inouye.
“The bottom line is that if you’re increasing pollinator crops, you also need to diversify crops and implement pollinator-friendly management.”
Researchers say they hope the research will encourage policymakers to reduce insecticide use, and plant edge rows and flower strips to provide nest sites and food for pollinators.
Consumers should also also look out for specific standards such as shade-grown coffee which is grown under a canopy of trees and supports much greater biodiversity.