November 7, 2008
UPDATED--In India, traditional farming method helps sustain bird diversity, study finds
A remote area of southwest India provides evidence that farming can support species conservation, according to a new study.
Published Nov. 3 in the Proceedings of the National Academy of Sciences, the study reveals that an agricultural landscape in this region contains the vast majority of native bird species found in adjacent forests.
The researchers focused on lands in the Western Ghats region that have been continuously farmed for more than 2,000 years, providing concrete evidence that under the right conditions, agriculture can co-exist with native species.
Relatively few species have been eliminated from this region since cultivation began, the study finds, citing two sources. One source are survey of records from the 1880s, which describe essentially the same species found in the region today. The second is a comparison of regional species to lists of species that inhabit similar but relatively undeveloped parts of India. The comparison suggests that the diversity of species in the Western Ghats region has remained largely undiminished over a vast period of time, Ranganathan said.
This conservation success is largely due to a supportive role that forests play in local agriculture production. "If it wasn't for the areca nut palm, the forests wouldn't be there," said Jai Ranganathan, lead author of the article, who earned a PhD in biology at Stanford in 2007. He is now a postdoctoral fellow at the National Center for Ecological Analysis and Synthesis.
Fallen branches and leaves from nearby forests are collected and transported to areca nut plantations where they are used as fertilizer and mulch to prevent soil erosion. Because farmers rely on these natural materials to maintain their land, the forests remain intact.
The forest-like structure of the areca nut plantations in the region also allows threatened species, such as the Great Hornbill and the Malabar Grey Hornbill, to exist there, adding to the crops' biodiversity value.
"This could be an important part of the conservation story for the entire Western Ghats region," Ranganathan said. The region extends 1,000 miles from north to south, running parallel to the west coast of India.
The area is a biodiversity hotspot, host to more than 1,000 vertebrate species, including birds, mammals, reptiles and amphibians.
Furthermore, the areca nut, also known as the betel nut, may prove to be a very valuable tool for conservation over a much broader area; it is grown throughout south and southeast Asia, a region facing some of the most severe conservation pressures in the world.
The areca nut palm not only supports species biodiversity by conserving bird communities, but also supports the economic livelihoods of local inhabitants, Ranganathan said. He called this a win-win situation for conservationists.
Many people living in the region maintain economic sustenance by harvesting and selling the fruit produced by the palm.
The areca nut grows in small, coconut-size clusters at the top of a slender palm tree. It is used by 10 percent of people in the world, primarily in Southeast Asia, who chew the nut to release chemicals that produce a mild, coffee-like alertness.
A high-value cash crop, it provides people living in the region with an economic incentive to keep the forests intact, Ranganathan says, instead of developing the land for other human use that would result in wiping out large numbers of species.
Without incentives, people are inclined to follow the economic drivers that prevail today without thinking about what effects it might have on the future, said Gretchen Daily, a biology professor and co-author of the paper.
In partnership with the Center for Conservation Biology, Daily, who is also a senior fellow at the Woods Institute for the Environment at Stanford, has been researching tropical biodiversity conservation for more than 15 years by conducting studies around the world in places such as Hawaii and Costa Rica.
She advocates a "game-changing view" of conservation that gets people thinking about going beyond nature reserves to contemplating ways of harmonizing human activities with conservation.
Traditional conservation philosophy supposes that in order to protect species from extinction, habitat areas have to be fenced in and locked away from human contact. But according to Daily, this strategy alone is "doomed to fail."
"Even if we ambitiously expand reserve areas in the future, it is likely that we'd protect in the long run only 3 to 5 percent of the Earth's plants and animals," Daily said. "That's such a tiny fraction, no one would call that a success."
"Our research helps to increase the potential for success in tropical species conservation by expanding the playing field," Ranganathan said. "Along with protecting pristine habitats, we can also include the vast agricultural areas that surround them in our conservation planning."
The research was funded by a David L. Boren Graduate Fellowship, the Winslow Foundation and Peter and Helen Bing.
This is an updated version of a release sent out earlier today (Nov. 7), including a clarification in the third graf.