Coffee is one of the world’s most widely consumed beverages, with a multibillion-dollar sector behind it spanning a lengthy value chain from the farm to the cafe table. As coffee production is largely in the hands of smallholder farmers, the livelihood value is immense, with an estimated 100 million coffee farmers worldwide. Global coffee trade relies on two species: Arabica (Coffea arabica) comprising c. 60% of traded coffee, and robusta (Coffea canephora), the remaining 40% . Liberica coffee (Coffea liberica), a third beverage species, is cultivated worldwide (and used as a grafting rootstock for Arabica and robusta) but is insignificant in terms of global trade . C. arabica, a product of the ancient hybridization of C. canephora and Coffea eugenioides, occurs naturally in Ethiopia and South Sudan; C. liberica and C. canephora occur wild across much of wet tropical Africa.

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Despite the overwhelming agronomic and economic success of Arabica and robusta, a myriad of new threats are now evident for the global coffee sector. These include climate change, especially the increasing incidence and duration of drought, the spread and escalating severity of devastating fungal pathogens, most notably CLR for Arabica in Central and northern South America, and coffee wilt disease (CWD; Gibberella xylarioides R. Heim & Sacca) for robusta in Africa, the emergence and/or spread of other diseases and pests, and social, economic, and market-based factors. Meeting these challenges will require clear vision, a broad range of interventions, and good governance. There will also be an increasing demand for germplasm: the raw material of crop development. Wild variants of Arabica and robusta will be of primary importance, but other wild coffee species [crop wild relatives (CWRs)] are likely to be required. Wild coffee species are once again coming into focus , reviving the considerable interest that existed during earlier eras of coffee research.

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Most consumers, and even many coffee sector representatives, are unaware that there are more than two or three coffee species. There are 124 coffee species known to science, occurring naturally (wild) in tropical Africa, the Indian Ocean islands (Madagascar, Comoros Islands, and Mascarene Islands), Asia, and Australasia. All Coffea species have the characteristic coffee bean (seed) morphology, and several of the noncommercial species are (or have been) used on a local or regional scale as a substitute for Arabica coffee. These species have useful traits for coffee development, such as climatic tolerance and especially drought tolerance, pest and disease resistance, low or zero caffeine content, and sensory (taste) amelioration.

Image result for Why are wild coffee species at a High extinction risk.

Most consumers, and even many coffee sector representatives, are unaware that there are more than two or three coffee species. There are 124 coffee species known to science, occurring naturally (wild) in tropical Africa, the Indian Ocean islands (Madagascar, Comoros Islands, and Mascarene Islands), Asia, and Australasia. All Coffea species have the characteristic coffee bean (seed) morphology, and several of the noncommercial species are (or have been) used on a local or regional scale as a substitute for Arabica coffee. These species have useful traits for coffee development, such as climatic tolerance and especially drought tolerance, pest and disease resistance, low or zero caffeine content, and sensory (taste) amelioration.

Image result for Why are wild coffee species at a High extinction risk.

Given the importance of coffee CWRs for coffee sector sustainability, two critical questions come into focus: What is the extinction risk of wild coffee species? And which species should be prioritized for conservation and crop development? To answer these questions, we report here a global assessment of extinction risk for all known coffee species by rigorously applying International Union for the Conservation of Nature (IUCN) Red List Categories and Criteria; a priority system for coffee CWRs, based on phylogenetic data and plant breeding information; and a gap analysis of ex situ conservation in germplasm collections and in situ conservation in protected areas.

At least 60% of coffee species are threatened with extinction

The application of the IUCN Red List Categories and Criteria resulted in 75 coffee species (60%) being assessed as threatened with extinction, including 13 Critically Endangered (CR), 40 Endangered (EN), and 22 Vulnerable (VU) species; 35 species were assessed as not threatened [Near Threatened (NT) or Least Concern (LC)], and 14 species were Data Deficient (DD). Information on individual species, including distribution range, habitat and ecology, threats, conservation actions, and assessment information, can be accessed via the IUCN Red List of Threatened Plant Species portal.

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The main drivers for coffee species extinction risk are small distribution sizes and low number of locations, i.e., “a geographically or ecologically distinct area in which a single threatening event will affect all individuals”, in conjunction with ongoing threats, particularly habitat loss. For almost all species, there is a continuing decline in the quality, area, and extent of available habitat. Habitat loss is mainly due to land use change, especially forest loss, predominantly because of agriculture (general), livestock farming, and settlement and development, mostly associated with farming.

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Timber collection is also a threat for many coffee species; coffee timber is often straight, hard, and termite resistant and frequently collected for minor construction purposes and fuelwood. On the basis of the research undertaken for this contribution, alongside other coffee research, and after more than two decades of field research, we propose that coffee species are extinction sensitive. Wild coffee species generally exhibit narrow climatic envelopes with restricted habitat (niche) specificity, have low adaptive potential, and are mostly forest dwelling. As with other members of the coffee family (Rubiaceae), they also require good quality habitat, have limited capacity for regeneration unless conditions are optimal, and do not act as pioneer species. There are, no doubt, other reasons for the prevalence of range restriction, including perhaps the presence of near-universal obligate outcrossing, due to strong gametophytic self-incompatibility

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Written by AfricaExplorerMagazine

African Explorer Magazine is a publication being run by African Media Professionals, Explorers, Scientists, Researchers and Writers. Our Media Platforms tells African Stories from an Africans Perspective.

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