Philpott, S. M., P. Bichier, R. A. Rice, and R. Greenberg. 2008. Biodiversity conservation, yield, and alternate products in coffee agrosystems in Sumatra, Indonesia. Biodiversity Conservation 17:1805-1820.
The vast majority of field research on biodiversity conservation in coffee agrosystems has taken place in Latin America. For that reason, there has been some criticism that using “shade coffee” for conservation may not apply to coffee growing regions in other parts of the world. So this paper, by well-known coffee researchers currently or formerly associated with the Smithsonian Migratory Bird Research Center, is a welcome addition to the literature.
This study took place in and around Bukit Barisan Selatan National Park in Lampung province, southwestern Sumatra. Last year, the World Wildlife Fund reported that 30% of the park has been lost to illegal agriculture, mainly coffee which was documented as having been purchased by Kraft and other large roasters (this post summarizes the report’s findings; more on the status of these farms later in this post).
This study looked at differences in vegetation, ants, birds, and crop characteristics between forest in the park, and coffee plots both within and outside the park. These farms all cultivate robusta, not arabica, coffee. Robusta is typically grown in full sun, but it has been shown to benefit (via higher yields) from some shade, especially in poor soil conditions.
Not surprisingly, and consistent with other studies, coffee plots, whether inside or outside the park, had fewer species of trees, ants, and birds than the forest. The forest had far more canopy cover, denser canopy thickness, taller trees, and more epiphytes than any of the coffee plots.
The Oriental White-Eye (Zosterops palpeborsus) was one of the most commonly encountered species in forest, but it was not found in coffee plots either within or outside the park.
Various metrics between coffee plots within or outside the park were actually quite similar, including amount of canopy cover (around 32%), and number of species of trees, ants, and birds. However, although the number of species was similar, there was very little similarity in the species composition of all taxa between coffee plots and forests. This is in contrast with studies looking at the same variables in Chiapas, Mexico, which found much higher similarity between forests and coffee plots. It indicates that these robusta coffee farms in Sumatra do not maintain most forest species.
There are some contributing factors that make coffee farms in this area poor reserves for biodiversity. Sumatran coffee farms use very few species of shade trees, including the non-native Gliricidia sepium, which may not provide proper resources for native fauna. In general, the farms had very poor soil conservation practices, no use of organic fertilizers or compost, and minimal ground cover. Farmers will need help in sustainable agriculture management to help alleviate these problems.
This will be challenging enough for the legal farms outside the park. As for the ones inside, some of the 15,000 families which have illegal plots in the park have been there for up to 20 years, and there is little place in the surrounding landscape for them to farm if they are removed — even if they are provided incentives for farming outside the protected area. Sadly, other studies have indicated that even if they are removed, forest recovery is slow in this area and expensive restoration efforts would likely be required in order to rehabilitate agricultural encroachments.
It sounds like the bulk of this coffee is sold to the large multinational roasters for grocery store blends, who could well afford to assist in developing sustainable agricultural in the area that supports biodiversity and farm family income. These results also suggest to me that consumers should be looking to buy sustainably-grown arabica coffee from Sumatra, purchased via roasters who have relationships with their farmers.
Photo by Lip Kee under a Creative Commons license.
Revised on October 30, 2020