Study alarms a "profoundly negative" impact of climate change on indigenous Arabica coffee in Ethiopia and world-wide
The Impact of Climate Change on Indigenous Arabica Coffee (Coffea arabica): Predicting Future Trends and Identifying Priorities
Excerpts
Source:
PLOSONE
(a peer reviewed open access journal)
Published
October 7, 2012
Abstract
Precise modelling of the influence of climate change on Arabica
coffee is limited; there are no data available for indigenous populations of
this species. In this study we model the present and future predicted
distribution of indigenous Arabica, and identify priorities in order to
facilitate appropriate decision making for conservation, monitoring and future
research. Using distribution data we perform bioclimatic modelling and examine
future distribution with the HadCM3 climate model for three emission scenarios
(A1B, A2A, B2A) over three time intervals (2020, 2050, 2080). The models show a
profoundly negative influence on indigenous Arabica. ...
Based on known occurrences and ecological tolerances of Arabica,
bioclimatic unsuitability would place populations in peril, leading to severe
stress and a high risk of extinction. This study establishes a fundamental
baseline for assessing the consequences of climate change on wild populations
of Arabica coffee. Specifically, it: (1) identifies and categorizes localities
and areas that are predicted to be under threat from climate change now and in
the short- to medium-term (2020–2050), representing assessment priorities for ex
situ conservation;
(2) identifies ‘core localities’ that could have the potential to withstand
climate change until at least 2080, and therefore serve as long-term in
situ storehouses for
coffee genetic resources; (3) provides the location and characterization of target
locations (populations) for on-the-ground monitoring of climate change
influence. Arabica coffee is confimed as a climate sensitivite species,
supporting data and inference that existing plantations will be neagtively
impacted by climate change.
Implications for
cultivated Arabica coffee in Ethiopia and world-wide
The outcome of climate
change for Arabica cultivation in Ethiopia, the only coffee grown in the
country, is also assumed to be profoundly negative, as natural populations,
forest coffee (semi-domesticated) and even plantations occur in the same
general bioclimatic space as indigenous Arabica. Forest coffee and semi-forest
coffee production systems account for c. 25% of total coffee production in
Ethiopia[4]. Production is likely to decrease
significantly in certain areas, and especially in locations that are presently
marginally suitable for coffee production. Most coffee cultivation in Ethiopia
is shade-grown and without irrigation, the latter being a practice that can
significantly influence the productivity and survival of Arabica in suboptimal
growing areas [60]. Unlike native forests, however, there
may be greater short term incentives to employ mitigation measures, such as
irrigation, particularly at the lower scales involved (e.g. at farm-level).
Our results provide
independent validation that Arabica is a climate sensitive species, supporting
data on recorded climate optima [3]–[6], results based on environmental envelope
methodologies [14],[15], and anecdotal information from coffee
farmers. The logical conclusion is that Arabica coffee production is, and will
continue to be, strongly influenced by accelerated climate change, and that in
most cases the outcome will be negative for the coffee industry. Optimum
cultivation requirements are likely to become increasingly difficult to achieve
in many pre-existing coffee growing areas, leading to a reduction in
productivity, increased and intensified management (e.g. the use of irrigation),
and crop failure (some areas becoming unsuitable for Arabica cultivation).
Detailed modelling of Arabica cultivation is required, on local and regional
scales, in order to inform famers and decision makers as to the requirements
for future-proofing the sustainability of their crop. The methodology used here
could be adapted for coffee plantations on a regional scale, by substituting
the location of plantations for indigenous populations, and by applying a
modified threshold approach based on the parameters encountered and employed in
cultivation.
Conservation of wild
Arabica coffee
Unlike cultivated
Arabica coffee, the distribution of indigenous populations is controlled almost
entirely by natural, biotic parameters, even though these factors are
influenced by anthropogenic actions. Assisted migration of wild Arabica could
be suggested as a possible means of mitigation, but in reality this option is
laden with constraints. Not least are the short-term financial implications
associated with resourcing a medium- to long-term and diffuse (i.e. involving
multiple populations) action of assisted migration. Re-locating coffee
plantations is likely to bring economic benefits within a realistic time frame;
the assisted migration of natural populations of Arabica coffee is not.
What we have shown
here is that under a range of emission scenarios some populations of Arabica
(occurring in optimal bioclimatic space) might be able to resist climate change
until 2080, at least in the absence of severely negative influences (e.g.
deforestation). We define these populations here as ‘core localities’ (Figure 7; high prediction totals across all
scenarios) and suggest that they should be assessed as candidates for the
long-term in situ conservation of Arabica in the face of
accelerated climate change. Examination of the main protected areas of Ethiopia
shows that some of the ‘core localities’ already fall within those established
protected areas [70] and have a reasonable to good degree
of protection (e.g. national parks and UNESCO biosphere reserves), although
many do not (Figure 7). Where there is a specific objective
for the in situ conservation of indigenous populations of
Arabica, such as the Yayu and Kafa Biosphere Reserves (Figure 7), the ‘core localities’ falling
closely outside these protected areas should be assessed and, if suitable, be
incorporated into protected area delimitation and long-term management. Other
‘core localities’ should be assessed on a case-by-case basis. Conversely, those
localities identified as marginally suitable for Arabica in the present-day (Figure 2B) and unsuitable in the short- to
medium-term (Figure 7), are suggested as priorities for ex
situ conservation.
Closely associated
with the need to identify populations for conservation will be the requirement
to assess the genetic variation of indigenous Arabica, and particularly in
relation to their bioclimatic profiles (either modelled or directly measured),
and physiological response to climate change. For example, genetic assessment
and monitoring of populations either side of the Great Rift Valley could be
rewarding, as they are already known to possess different bioclimatic
tolerances and other potentially valuable characteristics [30], [31]. These two main areas of distribution
receive the bulk of their rainfall from different directions and at different
times of the year [57]. In undertaking such work it might be
possible to identify local variants that have improved thermal and/or drought
tolerance, which can be used in the development of cultivated Arabica stock.
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Read the journal here: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0047981
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Editor: Brock Fenton, University of Western
Ontario, Canada
Received: May 18, 2012; Accepted: September 19, 2012; Published: November 7, 2012
Copyright: © 2012 Davis et al. This is an open-access
article distributed under the terms of the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original author and source are credited.
Funding: Part of this study was funded by the
Bentham-Moxon Trust (Royal Botanic Gardens, Kew) (http://www.kew.org/about-kew/policies-information/bentham-moxon/grants/index.htm).
Fieldwork in South Sudan was funded by the USAID JGMUST Project and World
Coffee Research (WCR) (http://worldcoffeeresearch.org/). Publication
costs were supported by World Coffee Research (WCR). The funders had no role in
study design, data collection and analysis, decision to publish, or preparation
of the manuscript.
Competing interests: The authors have declared that no competing
interests exist.