Even as more land is being used for agriculture, crop diversity has been on the decline.
Commercial farmers tend to grow crops that they can best profit from, yet this practice is leading to monocultures worldwide that could endanger global food security. In tandem, dominant farming practices are causing a loss of pollinators such as insects, which is also posing a threat to food supplies.
This is according to an international team of researchers who have examined global developments in agriculture over the half century between 1961 and 2016, based on data from the United Nations’ Food and Agriculture Organization (FAO). Global trends on the cultivation of field crops are clear, they say.
“The global increase in the proportion of land cultivated with pollinator‐dependent crops implies increased reliance on pollination services. Yet agricultural practices themselves can profoundly affect pollinator supply and pollination,” they write in a study published in the journal Global Change Biology.
“Extensive monocultures are associated with a limited pollinator supply and reduced pollination, whereas agricultural diversification can enhance both,” they elucidate. “Therefore, areas where agricultural diversity has increased, or at least been maintained, may better sustain high and more stable productivity of pollinator‐dependent crops.”
In other words, even as more and more land is being used for agriculture worldwide, crop diversity has been on the decline. This lack of diversity is a serious threat as crop failures can happen suddenly over large areas. Four-fifths of the 20 largest crops, for instance, require pollination by insects or other animals, yet other experts have reported alarming declines in the numbers of such pollinators in recent years.
One recent study has found that as much as 40% of the world’s insect species might go extinct over the next few decades. “Affected insect groups not only include specialists that occupy particular ecological niches, but also many common and generalist species,” the experts note. The causes include rampant pesticide use, the spread of pathogens, increased urbanization and climate change.
Such a massive loss of insects, which play essential roles in food chains and as pollinators worldwide, will deal a blow not only to natural ecosystems but to agriculture as well. With fewer pollinators around, crop yields will diminish.
However, researchers say, not all farms are or will be equally affected everywhere. By mapping geographical risks of crop failure based on FAO data, they point out that developing countries in South America, Africa and Asia are the most affected.
One reason is that in these regions monocultures are especially dominant with the majority of farms specializing in single crops such as oil palms and soybeans. “Soy production has risen by around 30 percent per decade globally,” explains Prof. Marcelo Aizen, a scientist at 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,” he adds.
Yet these poorer nations export much of their produce to richer ones and so crop failures in Asia, Africa and South America will have worldwide repercussions. “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 Robert Paxton, a member of the German Centre for Integrative Biodiversity Research.
To ward off chronic food shortages, diversifying agriculture worldwide is a must. So is cultivating crops in a more ecological manner. Farmers should “make the areas under cultivation more natural, for example by planting strips of flowers or hedgerows next to their fields and by providing nesting habitats on field margins,” the researchers say. “This would ensure that there are adequate habitats for insects, which are essential for sustainable and productive farming.”