A new landmark study conducted by researchers from WWF, Stanford University, and others finds that a forest in Costa Rica serves as home to bees that provide pollination services worth 7% of income ($62,000 on average) to a nearby coffee farm.
A new landmark study conducted by researchers from WWF, Stanford University, and others finds that a forest in Costa Rica serves as home to bees that provide pollination services worth 7% of income ($62,000 on average) to a nearby coffee farm. Coffee is one of the five most valuable agricultural exports from developing nations, its cultivation employs more than 25 million people worldwide. About 42,000 square miles (11 million HA) of the Earth are planted in coffee, an area larger than Virginia, and more are converted each year. Like two-thirds of the crops we eat, coffee plants depend at least partly on animal pollination to produce fully. Without bees and other animal pollinators, coffee yields around the world would be reduced substantially. This fact was recently confirmed by a World Wildlife Fund researcher, Taylor Ricketts, working together with a number of scientists from Stanford University and other academic institutions. In fact, Ricketts and his colleagues found that for one coffee farm in Costa Rica the pollination services provided by bees that make their home in a nearby tropical forest was worth around $62,000, or 7 percent of the farm’s annual income. The study, which appeared in the Proceedings of the National Academy of Sciences [see http://www.worldwildlife.org/forests/results/coffee.cfm], is the first to quantify in such detail the value of pollination services from native habitats. “The results show that natural ecosystems have very real economic value,” says Ricketts. “Even fragmented forests can have a significant value to an operation like a coffee farm but the forest needs to be nearby. With locally-provided services like pollination, location is key.” The study was conducted at a large coffee farm in the Valle General in Costa Rica, one of that nation?s most important coffee growing areas. The farm spreads across 1065 hectares (2361 acres) and is adjacent to two large fragments of tropical forest. Ricketts and his co-researchers were interested in seeing whether pollination levels ?and resulting yields? were higher for coffee plants that were closer to the forests compared to those farther away. Five coffee plants were selected at 15 sites on the farm, each farther away from forest patches than the next. On each plant, four branches were selected for study. Two were pollinated by hand, ensuring complete pollination, and two were left to be pollinated naturally. Yields on the two sets of branches were then compared to each other. The results proved to be most interesting: First, the study found that both coffee quality and quantity increased with proximity to the forest. This is not surprising given that researchers also found that the flowers near the forests received twice as many bee visits and twice as much pollen deposition compared to the flowers far from forests. This increased natural pollination translates into 20 percent greater yields and 27 percent fewer “peaberries,” ?which are small, misshapen seeds that are the result of incomplete pollination. The findings match well with previous studies which found that yields on coffee plants decreased by anywhere from 15 to 50 percent when bee visitation was prevented. At the research site in Costa Rica, the increase in yields was provided courtesy of 11 species of bees ?the non-native feral honey bee and ten species of native stingless bees? all of which depend on forests for their survival. “These wild bees don?t live on coffee farms,” explains Ricketts. “There just aren?t as many places for them to nest and there isn?t enough food to sustain them there throughout the year. So if coffee farms want pollination from wild bees, they need to provide a home for them and that means at least relatively intact forest.” While all the species of bees make their homes in the forest, they differed in how far they were willing to travel for food, and therefore in their effectiveness as pollinators. Wild bees, for instance, have a relatively short flight range, and therefore typically were found at coffee flowers near the forest. Honeybees, on the other hand, have longer ranges and were therefore responsible for a greater proportion of visits to coffee plants located farther away from the forest. Recent declines in non-native honey bees in many parts of the world ? affecting up to 80 percent of some populations – have many farmers concerned. As pollination by honey bees decreases, farmers are increasingly looking to wild bees to take up the slack. Previous studies have found that native bees are better pollinators than honey bees since they typically deposit more pollen on coffee flowers per visit. For this reason, maintaining a diverse community of pollinators provides insurance against population declines and is likely to increase pollination and crop yield. In the study that Ricketts and his colleagues conducted, they found that natives did indeed pick up the slack, but only in the areas near forest. In an opportune coincidence, honey bee populations around the study farm abruptly dropped in the middle of the study. In the sites far from forest, where honey bees were almost the sole pollinators, coffee flowers received 54 percent fewer visits by bees. But in sites near forest, some native species increased that same year to compensate, and visitation rates dropped hardly at all. And pollination isn?t the only service provided by forests and other native ecosystems. A study published in 1997 by economist Robert Costanza et. al. entitled The Value of the World’s Ecosystem Services and Natural Capital estimated that the planet?s ecosystem services are worth more than $33 trillion per year, nearly twice the global gross domestic product. That study, and others like it that have since followed, involved complicated sets of economic calculations. Ricketts? calculations, by comparison, were quite simple. “Earlier studies that looked at ecosystem services on a global scale were watershed events for conservation science,” says Ricketts. “They powerfully introduced the concept of ecosystem services to people in an understandable way. But they are not so useful for land managers, who typically face decisions at local scales, like whether to convert a forest to a coffee farm.” In order to bring these sorts of calculations down to a local scale that was of some utility to local farmers, Ricketts et. al. combined the data from the study with market prices for coffee. Their result ? that the pollination services provided by nearby forests were worth on average $62,000 per year for the farm?exceeds the value of many other common land uses. For instance, if the forest were turned to pasture for cattle, it would likely only earn some $24,000 per year. Indeed, because the farm does not own the patches of forest that are home to the pollinators on which its business depends, the pollination constitutes a sort of subsidy to the farm; a subsidy from the forest that is not valued and for which its owner is not compensated. The idea of paying forest owners for the services their ecosystems provide is not as novel as it may seem at first. In fact, Costa Rica is somewhat of a pioneer in this regard: owners of tropical forest in the country are compensated for conserving land through an innovative program of Payment for Environmental Services. Although the program is laudable, it still undervalues the services provided by forests, and would only pay the owner of the forest studied by Ricketts and his colleagues about $6,600 a year, one-tenth the estimated value of its pollination services to one coffee farm alone. The impact of the Ricketts et. al study remains to be seen, but Ricketts himself hopes it will be used by land planners responsible for tropical forests to make better conservation decisions. After all, proving that one ecosystem service alone is worth $62,000 to a single farm may boost conservation; especially in areas where competing land uses have been shown to be worth considerably less. “The challenge now is to find ways to compensate land owners for the services their lands provide,” concludes Ricketts. “Most ecosystem services are not valued until they disappear along with the income they generate. If the forest we studied were clear-cut, the coffee farmer would be $62,000 poorer.” What?s more, Ricketts is quick to point out that his calculations are almost certainly low, since he only looked at one farm ? others are also adjacent to the forest? and at one of the many services the forest provides. Water and air purification, carbon storage and other ecosystem services, were also not added into the equation. In the coming months Ricketts will visit Costa Rica to discuss his study and promote the benefits of interlacing farms and forests to environment ministers and land managers. Tom Lalley is Senior Communications Officer at the World Wildlife Fund, US. He can be reached at [email protected]
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