Native shade trees in coffee plantations vital for diversity, abundance of birds, says study

‘Alteration of canopy, woody plant composition can influence pattern of functional composition of resident birds’

Verdant coffee and tea plantations are more than an ideal backdrop for photos; they support a thriving avian population. In a study that underscores the need to understand the patterns and drivers of bird species composition and diversity outside Protected Area (PA) networks to develop landscape-level conservation strategies, researchers found that they varied in differently-managed plantations.

The findings were the result of collaborative work by Kannur University, Kerala, Salim Ali Centre for Ornithology and Natural History, Coimbatore, Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru, and Ferns Nature Conservation Society, Wayanad. It was published in July 2021.

Focussing on the coffee plantations in the Western Ghats, which are an important agro-ecosystem and help maintain a significant portion of regional avian diversity, the researchers compared the composition and functional diversity of resident birds between shade and open coffee plantations.

They counted 3,846 birds of 87 species, and found species richness to be higher in shade (78 species) than in open coffee plantations (55 species). “Interestingly, 32 species were unique to shade and nine were unique to open coffee plantations, with 46 species found in both types of plantation. Species richness and abundance were higher in shade coffee,” the study says, adding that the results reveal that different farm management practices can affect functional bird richness and its abundance in coffee plantations. They have made a case for retaining shade-trees of native varieties in coffee plantations to support high functional diversity, richness, and abundance of birds in the coffee plantation of the Western Ghats.

The study, ‘Resident birds show different patterns in species composition and functional diversity in differently managed coffee plantations in the Western Ghats, India’, was published by the Ornithological Science journal in July 2021.

Speaking to The Hindu, Santhanakrishnan Babu, one of the authors, said the study was conducted between May and August, 2016, in the northern part of Wayanad district. “Wayanad is a major coffee producer, producing 90% of the Kerala’s coffee. Our study aimed to understand how resident birds respond to differently-managed coffee plantations – shade and open,” he said.

The Kerala government recently passed an order to chop all resident trees on private land except sandalwood. This will lead to extensive chopping of resident trees from the coffee plantations which will affect biodiversity, he added.

Another author Athira S. Variar and Mr. Babu said retaining shade trees of native varieties in coffee plantations is important for supporting high functional diversity, richness, and abundance of birds. “Shade plantations support several habitat specialists and range-restricted birds, and alteration of the canopy and woody plant composition can influence the pattern of the functional composition of resident birds. Since our study covered only one season, year-round study in these plantations may shed more light on the composition of resident, breeding and migratory bird species,” they said.

Conservation strategies

They have called for landscape-level conservation strategies. Author Anoop N.R. pointed out that the Forest Department has little authority over the plantations located outside forest areas, and trees in these plantations are increasingly being replaced with exotic trees such as Grevillea robusta. “To promote the protection of large native trees in coffee plantations, we recommend initiating programmes to provide financial incentives to private landowners. Education programmes will also help to improve community support for retaining texisting indigenous tree varieties and promote planting more of the same,” he recommended, adding that a framework needs to be developed with regard to which species can be planted and which must be maintained, or removed, from the plantations.

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