Authors: Michelle Luiz
This is the second article from our three-part series titled Biodiversity Outside Protected Areas.
A study by scientists at NCBS and CWS found that coffee agroforests in Karnataka contain at least 86 different butterfly species. This supports the idea that agricultural areas can serve as a refuge for biodiversity.
It is common knowledge that globally, wildlife habitats are facing alarming rates of deforestation and fragmentation. Protected areas only cover around 15% of Earth’s land, leaving the remaining areas vulnerable to human exploitation. What is perhaps lesser known is that many species reside in the human-dominated agricultural spaces outside protected areas. Agroforestry plantations especially have been found to contain high amounts of biodiversity, as the main crop is grown alongside a variety of trees and shrubs.
Scientists at NCBS and CWS evaluated the role of coffee plantations in sustaining biodiversity using butterflies as indicators. They counted the number of butterfly species in 12 agroforests near Bhadra Tiger Reserve in Karnataka.
Traditionally, coffee is grown as an understory shrub beneath a native tree canopy. In recent years, however, farmers have taken to planting the faster-growing silver oak (Grivillea robusta) which is not native to the region. The result is a mixed agroforest consisting of coffee bushes, native trees and silver oak. The scientists analyzed the effects of factors like canopy cover and plant composition on butterfly diversity, expecting silver oak to have a negative impact.
By laying traps of rotten fruit, rum, and sugarcane juice, the research team identified as much as 86 different butterfly species living within the farms. As one would expect, diversity increased closer to Bhadra Tiger Reserve where likeness to the native forest is highest.
Interestingly the presence of the exotic silver oak had no overall effect on butterfly diversity. Nevertheless, the scientists are wary: the high proportion of native trees currently in plantations may have buffered the effects of silver oak. It is yet to be seen what happens as silver oak increases.
By demonstrating the potential of coffee plantations to serve as an effective habitat for butterflies, this study points to the importance of recognizing human-dominated landscapes as a viable home for native species. This may be particularly true in the case of the Western Ghats, where the large land area of agroforests potentially harbours a significant amount of biological diversity. To better understand the underlying ecological dynamics, the authors recommend research into why certain species seek plantations as habitats and whether this varies with season.
Research Article: Adult butterfly communities in coffee plantations around a protected area in the Western Ghats, India – J. Dolia, M. S. Devy , N. A. Aravind, and A. Kumar – Animal Conservation, 2007
You can find the original research article here.
You can find the Kannada translation here
