Scientists have found that good coffee needs trees – and bees to pollinate it.
Around the world, from Brazil to Ethiopia to Vietnam, small farmers depend on coffee for a livelihood. But as highlighted in C&CI on numerous occasions, a warming climate could adversely affect the coffee supply chain.
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Changes in temperature and rainfall may reduce coffee production in some areas, while making new places suitable for the crop, but scientist believe that climate change could also affect bees that pollinate the trees that produce coffee.
There is, however, some good news for coffee lovers. Scientists also believe that maintaining healthy forests close to coffee farms could help keep the buzz in your morning joe. That’s what a new study published in the Proceedings of the National Academy of sciences (see box), which was highlighted by the Centre for International Forestry Research (CIFOR)*.
“At a time when agricultural production is threatened by climate change, the ecosystem services provided by forests – in this case, pollination – can help farmers cope and adapt,” said Bruno Locatelli, an expert on ecosystem services and climate change adaptation at CIFOR and a co-author of the study.
Other studies have shown that climate change is likely to affect agriculture. Some farmers may have to shift crops to higher ground, while others may need to change to other products that are more suitable to their new growing conditions.
However, few studies have examined the combined impacts of climate change on crops and the ecosystem services important to farmers, said Pablo Imbach, a climate and ecosystems scientist at the International Center for Tropical Agriculture (CIAT).
Although people generally associate forests with ecosystem services such as maintaining water quality or moderating temperatures, their role as a home for bees often flies under the radar, Imbach said.
“We wanted to take a different approach,” he explained. “Our idea was to look not only at how conditions suitable for coffee crops might change with climate change, but how that would couple with changes in ecosystem services – pollination services, in this case.”
Because Arabica coffee, which accounts for two-thirds of the world’s coffee production, is self-pollinating, technically it doesn’t need bees at all, Imbach said.
Giving coffee trees a boost
But bees, especially native species, give coffee trees a boost. As the number of bee species – known as ‘species richness’ – found on a coffee farm increases, so does the farm’s productivity. The trees set more fruit, the fruit weight is higher, and yield is greater.
With climate change in Latin America, though, the places where coffee is grown and where bees thrive today could shift in future. In a region where 80 per cent of coffee is grown on plots of less than four hectares, that could have a big impact on small-scale, low-income farmers.
Area suitable for coffee expected to shrink
Areas currently suitable for coffee production in the region will shrink by 73 per cent to 88 per cent under scenarios of moderate to high warming, according to the study, which examined the impact of 19 climate variables on areas suitable for coffee crops and 39 bee species in Latin America.
Meanwhile, up to 30 per cent of areas suitable for coffee production in the future will be places where coffee is not currently cultivated, giving other farmers a chance to grow an important cash crop.
In 10 per cent to 22 per cent of future coffee-producing zones, coffee suitability will increase and the number of bee species will increase, an effect known as ‘positive coupling.’ That is especially true in Central America, the study found.
The opposite – negative coupling, or a decrease in both coffee suitability and bee species richness – is likely to occur in 34 per cent to 51 per cent of future coffee-producing zones.
Some areas will be more suitable for coffee growing
About one-third of future coffee-growing zones show an increase in coffee suitability and a decrease in bee species, while no more than 10 per cent show more bee species in areas that lose suitability for coffee production.
Overall, the average number of bee species per hectare could plummet to no more than three in Latin America.
The news is better for coffee farmers, though, as virtually all coffee-producing areas are still likely to maintain at least five bee species, and about half the areas will be home to 10 species, the study found.
Plan now for future scenarios
Scientists see the changes as a wakeup call. Good planning now could help farmers adapt in the future, enabling some to maintain their coffee trees whilst giving others, in less suitable areas, time to shift to other crops.
Most areas suitable for coffee crops, both now and in future scenarios, were within 1,600m of forests. That’s a strong argument for maintaining or restoring mosaic landscapes that combine forest and agriculture.
“In order to attract bees when the coffee is flowering, you need bee communities to be around the whole year,” Imbach said. “The way to increase productivity is to have forests close to coffee plantations, so bees can nest in trees and survive all year.”
Healthy forests have other benefits too
Keeping bees buzzing in forests will bring other benefits, too, Locatelli said. “Patches of forest that host bees can provide many other ecosystem services. The microclimate regulation, water regulation and erosion control that are provided by forests in the landscape are also important for agriculture.”
Farmers and planners should think not only about keeping forests intact, but also about restoring forest patches to help reduce future climate impacts on coffee crops and bee habitat, Imbach said.
Forest restoration with native species can protect biodiversity and create corridors for animals that disperse seeds. Corridors in mountainous areas can give both tree species and animals room to migrate toward cooler conditions uphill.
Although there is plenty of evidence that climate change will affect agriculture, there is an urgent need for research that will help smallholders, especially those in poor, rural areas, prepare for future impacts, the researchers said.
“We focused on looking at areas suitable for coffee cultivation, but we don’t know how that will affect the productivity, in terms of tons of coffee production,” said Imbach.
Species richness increases productivity
And although studies show that greater bee species richness increases coffee productivity, scientists still don’t know enough about the relationship between coffee and pollinators to make precise predictions.
“We need more research on agricultural management to help farmers mitigate the effects of climate change, not just on crops, but also on ecosystem services,” said Imbach.
“Many people think they will be able to adapt crops to future conditions, but that might not always be the case,” he concluded. “There is a big question of how to plan for development in areas where crops that are currently grown will no longer be suitable.”
Those are the kinds of studies that will create a buzz among farmers and climate scientists in the future.
The research highlighted here forms part of the CGIAR Research Programme on Forests, Trees and Agroforestry.
For more information on this topic, please contact Bruno Locatelli at .■ C&CI
Coupling of pollination services and coffee suitability under climate change
Climate change will cause geographic range shifts for pollinators and major crops, with global implications for food security and rural livelihoods. However, little is known about the potential for coupled impacts of climate change on pollinators and crops.
Coffee production exemplifies this issue, because large losses in areas suitable for coffee production have been projected due to climate change and because coffee production is dependent on bee pollination.
“We modelled the potential distributions of coffee and coffee pollinators under current and future climates in Latin America to understand whether future coffee-suitable areas will also be suitable for pollinators,” said the authors of the study (see below).
“Our results suggest that coffee-suitable areas will be reduced 73-88 per cent by 2050 across warming scenarios, a decline 46-76 per cent greater than estimated by global assessments.
“Mean bee richness will decline 8-18 per cent in future coffee-suitable areas, but all are predicted to contain at least five bee species, and 46-59 per cent of future coffee-suitable areas will contain 10 or more species.
“In our models, coffee suitability and bee richness each increase (positive coupling) in 10-22 per cent of future coffee-suitable areas.
“Diminished coffee suitability and bee richness (negative coupling), however, occurs in 34-51 per cent of other areas.
“Finally, in 31-33 per cent of the future coffee distribution areas, bee richness decreases and coffee suitability increases. Assessing coupled effects of climate change on crop suitability and pollination can help target appropriate management practices, including forest conservation, shade adjustment, crop rotation, or status quo, in different regions.”
Authors: Imbach, P.; Fung, E.; Hannah, L.; Navarro-Racines, C.E.; Roubik, D.W.; Ricketts, T.H.; Harvey, C.A.; Donatti, C.I.; Läderach, P.; Locatelli, B.; Roehdanz, P.R.
Publication Year: 2017
Source: Proceedings of the National Academy of Sciences (PNAS) 114(39): 10438-10442
DOI: 10.1073/pnas.1617940114 ■ C&CI