Coffee can give many species a boost - conversion of coffee shade plantations to sun plantations reduces protection for wildlife - Brief Article

Science News, August 31, 1996 by Tina Adler

Humans aren't the only creatures that rely on coffee to get through the day-so do a wide variety of wild birds, insects, and other animals, studies demonstrate.

Many animals live on traditional coffee plantations, in the abundance of trees and bushes that the farmers cultivate along with the coffee crop. Growers, however, are quickly converting to agricultural methods that produce higher yields but offer much less protection for wildlife, Ivette Perfecto of the University of Michigan in Ann Arbor and her colleagues explain in the September BioScience. They focused their report on Latin America, but they say that the trend is widespread.

The high-yielding approach grows coffee bushes in full sun, without the diverse ground cover and canopy that the old-fashioned farms feature. The so-called sun plantations have little food or shelter to offer wildlife. "Even the most cursory observation in sun plantations shows them to be almost devoid of birds," the researchers report.

Shade plantations, on the other hand, often serve as species-rich islands in otherwise deforested regions. They may feature more than 40 different types of trees, including fruit trees. Their canopies house epiphytes, parasites, mosses, and lichens, which themselves support insects, amphibians, and other animals, the authors note. The diversity of insects and migrant, forest birds on these farms rivals that seen in tropical forests.

By describing how quickly land is being converted from shade to sun plantations, Perfecto's report sounds an alarm, says ecologist Michael Huston of the Department of Energy's Oak Ridge (Tenn.) National Laboratory.

Growers began switching methods in the 1970s. In Brazil, the world's leading coffee producer, almost all farmers now grow the bean without shade. In northern Latin America, from Mexico to Columbia, farmers have converted almost half of their coffee production-about 1.1 million of the region's 2.7 million coffee-producing hectares, Perfecto and her colleagues report.

The growers originally switched to sun plantations, which have drier soil, to save their plants from a common leaf rust that thrives in moist conditions.

The rust never proved as destructive as anticipated, but now higher yields tempt farmers to convert. However, cultivating sun-grown coffee costs 39 cents per kilogram more than producing the shade-grown bean. Sun plantations spend more on chemical pesticides and fertilizers; on shade plantations, ants and spiders help control pests, and plant litter adds soil nutrients.