A new study published in the December 23rd issue of Current Biology, a Cell Press publication, reveals another "eco-friendly" reason to select shade-grown coffee over beans that were grown in the sun: Shade coffee farms not only harbor a diverse array of birds and bats, but they also help to maintain the genetic diversity of native tree species.
"Shade coffee farms allow birds and bats to move and disperse seeds throughout the coffee landscape, promoting plant gene flow," said Shalene Jha of the University of Michigan. "This is unlike most agricultural systems, which do not provide habitat for seed dispersers, and thus limit the distance plant seeds can move. By supporting important seed dispersal processes, shade coffee farms maintain plant population gene flow across fragmented habitats."
Gene flow refers to the transfer of genes from one population to another by interbreeding. The maintenance of gene flow is an important conservation measure since fragmented populations are effectively smaller and therefore more susceptible to inbreeding and further declines or extinction.
Coffee is grown across millions of hectares of land within the world's richest centers of biodiversity, the researchers said. In tropical America, that coffee is traditionally grown under a diverse canopy of shade trees, which supports a broad spectrum of pollinators that increases coffee yield. Unlike sun coffee grown in monoculture, shade coffee also provides habitat to a wide array of other animals, including bats and migratory birds that aid farmers by picking off insects. Earlier studies had suggested that birds and other animals within shade coffee farms might have additional ecological benefits.
Now, the researchers have confirmed that notion through genetic analyses revealing recent colonization and extensive gene flow of native understory tree species in shade coffee farms of Chiapas, Mexico. The findings show that traditional coffee farm
|Contact: Cathleen Genova|