Resilient bees brighten coffee’s climate-change outlook

Predictions of dramatic decreases in coffee supply thanks to climate change may be overblown, and salvation may come from resilient bees.

That’s the prediction arising from new modelling from a team of researchers from the US, Panama, Vietnam, Costa Rica, Peru and France, and published in the Proceedings of the National Academy of Sciences.

The team, led by David Roubik of the Smithsonian Tropical Research Institute took a fresh run at models used to predict habitat and biodiversity in coffee-growing areas of Latin America.

A number of studies over the past few years have found that climate change will negatively impact the coffee industry, particularly in Central America and in parts of South America. 

“Globally, we predict decreases in climatic suitability at lower altitudes and high latitudes,” concluded a 2015 study led by Oriana Ovalle-Rivera of the International Centre for Tropical Agriculture in Colombia, and published in the journal PLOS One

Roubik and colleagues, however, decided to re-examine the data by including an extra assumption. “Traditional models don’t build in the ability of organisms to change,” he explains. 

“They’re based on the world as we know it now, not on the way it could be as people and other organisms adapt.”

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Building resilience into the models produced a new result that, while not contradicting earlier conclusions, was significantly less pessimistic.

Previous studies have forecast steep declines in numbers for a bee species in Latin America. The new study, by incorporating the idea that some species will show a measure of adaptation to changing conditions, found a far less uniform outcome.

In all scenarios modeled by the team, at least five bee species remained in coffee-growing regions, and in some circumstances the number was as high as 10.

In some of these scenarios the total bee population, as well as species numbers, may decrease, but the scientists suggest that this effect could be countered by changing cultivation practices. Planting trees and shrubs favoured by native bees, for instance, can bolster numbers – and exploit the preference for coffee bushes to grow in sheltered conditions.

Perhaps ironically, one of the hero species to emerge from the modelling is the African honey bee (Apis mellifera) – an exotic species accidentally introduced in the 1970s. Ever since, some ecologists have been predicting that the aggressive interloper would out-compete native species and damage the environment.

Roubik has studied the impact of the bee in Panama, and as early as 2001 reported in the journal Population Ecology that its effect was, contrary to expectations, largely positive for native species. By pollinating plants at a faster rate than its competitors it ended up fostering a greater abundance of flowers, thus providing more, not less, feeding opportunities for the natives.

In the same way, if Roubik’s team is on the money, the same bee could end up being the saviour of the coffee industry. It is an outcome that is, in one respect, entirely fitting.

“Africanised honey bees in the Western Hemisphere both regulate their nest temperature and their own body temperature using water,” Roubik says. 

“When the climate is hotter – unless it’s too dry – they’re better adapted to endure climate change and pollinate coffee – an African plant.”

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