Dr Aaron Davis was not sure what he would find when he joined an expedition into the wilderness of Sierra Leone in December 2018 undefined
The Head of Coffee Research at the Royal Botanic Gardens, Kew travelled to West Africa to search for the fabled highland coffee of Sierra Leone, known to the scientific community as Coffea stenophylla.
The coffee had not been seen since the 1950s, and after lengthy communications with Professor Jeremy Hagar of the University of Greenwich, the men became determined to find it.
“This coffee from Sierra Leone is something that I’ve been interested in for many years, and so have other people,” Davis tells Global Coffee Report. “The interest is mostly founded on books from the late 1800s and early 1900s, which clearly state this is a coffee with an incredible flavour. There is one account that says it tastes better than Arabica.
“Immediately, the bells start ringing, ‘something better than Arabica? Really?’ That instantly makes anyone interested in coffee excited, and it’s a really compelling story. I’ve always wanted to go to Sierra Leone to see this coffee, where it grows, and as a coffee drinker, taste it.”
Davis and Hagar’s search began at farms in the area, where they hoped to find a fruiting coffee plant from which they could test the coffee. After multiple unsuccessful attempts, Davis knew they had to start looking in the wild to find the elusive coffee.
“There has been a lot of deforestation in Sierra Leone, so Jeremy and I knew we may not find it. We tried lots of different routes to reach the wild places where this coffee was last seen, and eventually, we found one plant,” he says.
“One plant is exciting, but if you remember your coffee biology, apart from Arabica, most species are self-incompatible, meaning it needs another individual to cross-pollinate with to produce fruits. You can’t produce coffee from one tree.”
The team continued its search, eventually discovering a small population of the highland coffee several hours east of the first location at the exact same altitude.
“The unfortunate thing was that there was no fruit, so we could not evaluate the sensory attributes of the coffee,” Davis says. “We were able to take some material, which is now being grown in Sierra Leone. It looks like we may have to wait at least four years before we can do our evaluation.”
C. stenophylla is one of the 75 wild coffee species Kew revealed was under threat of extinction in research published in Science Advances in January, 2019.
Two coffee species, Coffea arabica and Coffea canephora, commonly known as Arabica and Robusta, dominate coffee production, making up approximately 60 and 40 per cent of commercial crops respectively. But these are only two of the more than 120 species of coffee that can be found in the wild. Other species include Coffea ambongensis and Coffea pterocarpa, or the Ambongo and wing-fruited coffees of Madagascar.
Kew conducted an extinction risk assessment using the categories and criteria laid down by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species for all 124 confirmed coffee species. The study determined that 13 species are Critically Endangered, 40 are Endangered, and 22 are Vulnerable. Fourteen species were not assessed due to a lack of data and were unlocatable by Kew. Some of these 14 may already be extinct.
The study says the main drivers for the extinction risk are small distribution sizes and a low number of places where the species grows in the wild, in conjunction with ongoing threats such as habitat loss. Davis says the study also examines what this means for the future of commercial coffee production.
“Some people will say wild coffee species have little or nothing to do with [the coffee industry], but the coffee consuming and production landscape would look very different if we hadn’t been able to go back and supplement from wild stock to overcome problems like coffee leaf rust and other diseases,” he says.
“We’re looking at coffee species that could bring something to the development of better climate and disease resilience in Arabica and Robusta.”
Davis adds that climate resilience is not the only attribute wild coffee has to offer the industry.
“If you look at the history of coffee cultivation, we have adopted wild species to ensure the sustainability of the industry. A really good example is Robusta, a more or less unknown plant 100 years ago. Now it’s a multi-billion-dollar commodity,” he says.
“It’s something we often take for granted, but studies show that we’ve gone back every 30 years or so for something from the wild. In the case of Robusta, we went back to Africa and adopted a whole new species.”
Included among the coffee species under threat of extinction is the wild counterpart to Arabica coffee.
In a second report, published in Global Change Biology in January 2019, Kew and Ethiopian partners analysed the role climate change plays in the endangerment of wild Arabica.
When initially evaluated with the IUCN Red List, the assessment suggested Arabica was not threatened with extinction. However, after factoring in climate change, its status moved upwards from Least Concern to an Endangered species.
Kew has extensively studied the effect climate change will have on Arabica in Ethiopia. This provided much of the necessary information not available for the other 123 species to project how the plant will fare in the future.
In 2012, Kew predicted the number of locations where Arabica grows in the country could decrease as much as 85 per cent by 2080. In 2017, it turned its attention to the influence of climate change on coffee farming, showing that up to 60 per cent of the land used for Ethiopia’s coffee production could become unsuitable by the end of the century. The 2019 paper looked exclusively at the extinction risk for Arabica in the wild.
“If you applied that data to all other coffee species, you would almost certainly see them move up into a higher risk extinction category as well. Sixty per cent is alarmingly high, but it can be viewed as conservative because we haven’t factored in climate change to the same extent for all those other species,” Davis says.
Though the IUCN Red List deems 40 per cent of wild coffee species are not at risk of extinction, Davis says it is important not to prioritise strengthening these species over those in danger.
“They are generally species that have very wide distributions, like Robusta in the wild, which occur over very large areas. What you wouldn’t want to lose is a diverse genepool in the wild. It’s not just a question of losing a species, it’s about losing genetic diversity,” he says.
“For example, if you look at where Gesha occurs in Ethiopia, there’s almost no forest left. If we don’t do something soon, Gesha will be lost in the wild. These wild-type plants are almost unchanged since they began being commercially developed.”
Davis says protected areas and national parks need to incorporate and improve management plans so these species can be conserved, such as those established in Ethiopia.
“The Ethiopian government has designated reserves for the conservation of wild Arabica coffee,” Davis says. “They have production forests which surround pristine forest areas, conserving the most important reserves for wild C. arabica in Ethiopia.”
Kew works with Union Hand-Roasted Coffee in the UK to help farmers adjacent to these protected areas to improve the quality of their coffee. This results in higher prices that improve income, putting value into the forests where the coffee is grown, and buffering the wild Arabica coffee nearby.
“When we started talking to the farmers and the community in this protected area, they were saying ‘you’ve got your protected area, but what about us? We’re looking after the forest but there’s no payback for us.’ The objective [of this project] is to address that imbalance,” Davis says.
If conservation practices prove insufficient, Davis warns that greater lengths will need to be taken to protect wild coffee, such as assisted migration.
“If, for example, one forest was cut down or was faltering because of a changing climate, hypothetically you could move that coffee to higher altitudes of better suited areas,” Davis says. “This is largely theoretical, but it has been done with certain plant species. The problem is it’s very expensive and there is no financial incentive. Why we suggest it as a possibility is because it would be a last resort.”
Davis says that although he is unsure if under-studied wild species, such as the highland coffee of Sierra Leone, can assist in improving coffee crops’ resistance to disease and climate change, it is important the industry finds out, and quickly.
“[C. stenophylla] occurs in hotter, drier places than robusta. Could it have climate resistant potential? We don’t know, but unless we start looking at these things and other possibilities now, our options will rapidly diminish,” he says.