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Dam puts wild coffee species at risk of extinction

Coffee may be one of the world’s most popular hot (and cold) drinks, however few coffee drinkers may know that there are dozens of different coffee species in the world and some are even endangered. Only discovered in 2004, Kihansi coffee (Coffea kihansiensis), makes its home in the Udzungwa Mountains of Tanzania. A new study in mongabay.com’s open-access journal Tropical Conservation Science finds that the Kihansi coffee is nearing extinction due in part to a hydroelectric dam built upstream that has severely impacted the Kihansi River.



“Increasing evidence indicates that a range of animal and plant taxa, and the gorge ecosystem in general, have been severely disrupted by diversion of the river. The after-effects include changes in community composition and structure of birds, insects, and plants in the gorge wetlands,” the authors of the paper write. Already, the dam has pushed the Kihansi spray toad (Nectophrynoides asperginis) to extinction—although fortunately the species still survives in captivity—but now researchers fear it will do the same to Kihansi coffee, which is listed as Critically Endangered by the IUCN Red List.



The new study finds that less moisture from the river has impacted plant growth, essentially stalling growth at a particular height. In addition half of the plants surveyed showed evidence of parasites. In light of these threats the authors recommend ongoing monitoring of the population, additional research, identification of the plant’s seed dispersers, establishing a new population, and growing the species in a seed bank.



The authors argue that Kihansi coffee “could potentially be useful as a genetic resource to improve coffee production, for instance by incorporating disease resistant strains from other species, thus contributing greatly to improved coffee production in rural communities.”






CITATION: Rija, A. A., Mwamende, K. A. and Hassan, S. N.. 2011. The aftermath of environmental disturbance on the critically endangered Coffea kihansiensis in the Southern Udzungwa Mountains, Tanzania. Tropical Conservation Science Vol. 4(3):359-372.








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