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Wednesday, July 18, 2018

The Birds and the (coffee) Beans: any variety will do

The survey results suggest that coffee cultivation in the Western Ghats has not been inimical to the ecosystem or the endemic avian population.

By: Express News Service | Published: February 20, 2018 4:38:23 am
Changeable hawk-eagle, Coppersmith barbet.

In recent years, the consumption of coffee has grown worldwide, even as production has dropped significantly in the tropical American regions and Africa. In India, coffee acreage has increased by 150% between 1990 and 2015. Most of this expansion has taken place in the Western Ghats, the bean’s preferred home in the country.

As the area under coffee has expanded, increasingly larger numbers of planters have been choosing the hardier, less resource-intensive Robusta variety of the bean — even though the clear consensus among coffee connoisseurs is that the other variety, Arabica, is more flavourful.

But does this preference have an impact on the environment? The question is important because conservationists have often expressed concern that coffee shrubs damage the vibrant tropical ecosystems in which they typically grow. And the Western Ghats, where the bulk of India’s coffee is grown, is an especially fragile ecosystem.

To test the differential impact of Robusta and Arabica coffee cultivation on the local ecology, researchers carried out a survey of bird species in the plantation areas, looking out for trends in numbers and varieties of species. “We evaluated whether or not the two species of coffee grown globally — Coffea arabica and C. canephora (denoted “robusta”) — had equivalent avian conservation value in the Western Ghats, where Robusta production has become increasingly dominant,” the researchers wrote in their paper, published online on Friday.

The study found that while Arabica was more profitable, Robusta farms generally had the same abundances of bird species, “largely due to dense canopy and landscape-level forest cover”. Also, “farming practices, chiefly pesticide use, may affect the suitability of coffee agroforests as habitat” for birds, the study found — “at present, Robusta farmers tended to use less pesticide”.

Nilgiri wood pigeon, Grey-headed bulbul

Despite increasing preference for Robusta over the past two decades, Arabica still accounts for about 60% of the global coffee production; Robusta for the bulk of the remaining 40%. While Arabica is generally grown in shaded, low-intensity areas, full sun monocultures are common for Robusta cultivation.

The researchers, from the Wildlife Conservation Society, Princeton University, and the University of Wisconsin-Madison, surveyed 61 agroforests in the Chikmagalur, Hassan and Kodagu districts of Karnataka. These included 30 Arabica and 31 Robusta plantations. The median canopy density score for the Arabica plantations was 94.6%, that for Robusta was 79.2%. Across the plantations, as many as 204 species of birds were counted, including three IUCN Red-Listed species.

While the Arabica plantations were more avian species-rich, bird communities in the Robusta agroforests included many fruit-eating species that help in dispersing seeds. Significantly, only 19% of Robusta plantation owners used insecticides as compared to 75% of Arabica farmers.

The survey results suggest that coffee cultivation in the Western Ghats has not been inimical to the ecosystem or the endemic avian population. Although plantations often lead to a significant transformation in the landscape, a concerted effort to maintain canopy cover will continue to attract diverse avian species, the study suggests.

Environment Assessing impact: Published in Scientific Reports, on February 16, 2018; Authors: Krithi K Karanth, Charlotte H Chang, and Paul Robbins

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