Rainforest agriculture preserves bird biodiversity in India
Jeremy Hance, mongabay.com
November 4, 2008
A new PNAS study offers hope that agroforestry can conserve tropical forest biodiversity.
Conservation of biodiversity and agriculture have long been considered conflicting interests. Numerous studies have shown that when agricultural replaces a forest, biodiversity greatly suffers. However a new study finds it doesn't have to be that way.
In a paper published this week in PNAS, researchers found that Indian farmers in the Western Ghats grew a successful and economically beneficial crop while largely preserving the bird biodiversity of a pristine forest. Agricultural areas planted with arecanut palm retained 90 percent of the bird species from the adjacent forest. The researchers believe such biodiversity may be preserved long-term, since the study area has been continuously cultivated for two millennia.
According to the authors there are two fundamental reasons why this agricultural area has retained such a rich avian biodiversity. First, the crops leave a “high vertical structural complexity” of the forest intact, providing varied homes for many different bird species. Second, the crops are grown near forests, which the farmers use to collect leaf litter for mulch.
Great Hornbill, one of the species found both in forest and arecanut plantations. This magnificent bird is the largest in the hornbill family.
The researchers found that arecanut possessed even more conservation importance than retaining bird biodiversity. Requiring large amounts of water, arecanut is grown in increasingly threatened lowland forest. In this area of India lowland forests are often cleared for rice production, which does not preserve biodiversity. The authors note that "this production system sustains a rich avifauna compared with many other agricultural areas cleared from tropical forests (e.g., oil palm plantations)".
Arecanut crops produce betel nut, a mild stimulant consumed by 10 percent of the world. The crop has high economic benefits and is grown in such a way that allows for other corps to be planted in the same area, such as vanilla, pepper, banana, and coconut.
The researchers believe that there findings have importance not just for Asia but Central and South America as well. Shade grown coffee is becoming increasingly important in these regions, and like arecanut palm, shade grown coffee retains biodiversity because of the preservation of the vertical forest system.
How biodiversity can live with agriculture. Jai Ranganathan, R.J. Ranjit Daniels M.D., Subash Chandran, Paul R. Ehrlich, and Gretchen C. Daily. PNAS, November 3rd, 2008.