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Cocoa shortfall: Pollination curbs climate risk to cocoa

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Thomas C. Wanger at Westlake University
Thomas C. Wanger
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Correspondence
Pollination curbs
climate risk to cocoa
Cocoa yields will be 75,000
tonnes short of those predicted
for the 2013–14 growing season
(see go.nature.com/ob6eyt).
Supply deficits have been linked
to extreme weather events in the
cocoa-growing regions of Côte
d’Ivoire, Ghana and Indonesia,
so future production strategies
should take climate change into
account (see P.Läderach etal.
Clim. Change 119, 841–854;
2013).
The global trade in cocoa is
worth US$10billion per year,
Citation databases
omit local journals
South America’s research impact
is underestimated in the main
citation databases, as you suggest
(Nature 510, 202–203; 2014).
However, incorporating the
Scientific Electronic Library
Online (SciELO) Index into
Thomson Reuter’s Science
Citation Index will not rectify the
situation.
SciELO captures only a
fraction of the continent’s
peer-reviewed publications. For
example, it indexes papers from
just 267 of Brazil’s 1,909 journals.
Coverage by Elsevier’s Scopus
database is also inadequate.
According to Latin America’s
most comprehensive database on
scholarly journals, the Latindex
Catalog, 4,882 journals in South
America meet specified editorial
Forest devastated by
mining is reborn
Open-pit gold mining leaves
millions of hectares of wasteland,
particularly in the tropics. A
series of affordable, socially
inclusive and ecologically sound
forest-restoration projects in
Colombia could become a model
for rescuing mined lands around
the world.
Reforestation began in
2002 across 1,290 hectares in
Cácerces, one of Colombia’s most
conflict-ridden regions (see L.G.
Moscoso Higuita Reforestation: A
Natural Process; Editorial Colina,
2005). Projects using similar
techniques have since begun in
other areas of the country.
First the barren landscape
is reshaped using a bulldozer,
and the soil is enriched with
composted sewage sludge, benign
microorganisms and other
nutrients. Next, Acacia mangium
trees are planted (because of their
hardiness, fast growth and ability
to improve soil by fixing nitrogen
and providing abundant leaf
litter), along with 10–20 native
tree species.
After ten years, the
A.mangium trees are logged
and replaced with well-adapted
native species to encourage
diversity. The Cácerces site now
contains more than 120 different
Breast-screening
trials are ethical
The ethics have been questioned
of running new randomized
controlled trials to determine
the benefits and possible harms
of population screening for
breast cancer (see go.nature.
com/vw13jv). As an ethics
representative on the Swiss
Medical Board, I believe that there
is a moral requirement for this type
of study. We need to ascertain
whether advances in treatment
have cancelled out the benefits
of early diagnosis through
screening.
The random allocation of
women into groups that have
mammograms with different
detection thresholds (see
H.G. Welch The New York
Times 29December 2013;
go.nature.com/scyt6b) or no
mammogram would be ethically
problematic if we knew that
screening provided a significant
net benefit. But this has not
been established.
I contend that most women
would prefer to participate in
a trial that helps to clarify the
benefit of screening, rather than
continuing to be subjected to
screening of doubtful benefit
and with potential for significant
harm through overdiagnosis.
Nikola Biller-Andorno
University of Zurich, Switzerland.
biller-andorno@ethik.uzh.ch
native tree species and harbours
an impressive range of wildlife,
including jaguars, sloths and
several species of primate.
Local people are involved in all
steps of the restoration process,
and they share in the social and
economic benefits generated,
such as increased employment
and proceeds from timber sales
and carbon credits. These will
more than compensate for the
initial investment of US$3,000
per hectare.
Evert Thomas Bioversity
International, Cali, Colombia.
e.thomas@cgiar.org
and 50million people depend
on cocoa farming. Farmers
are under pressure to stabilize
yields, often by increasing
chemical inputs and removing
shade trees to increase the
productivity of cocoa trees. But
both strategies could kill vital
pollinators.
Farmers need to adopt more
sustainable ecological methods.
For example, shade trees can
make plantations more resilient
to drought and provide habitat
for pollinators. Increasing insect
pollination by as little as 10%
can double cocoa yields (see
J.H.Groeneveld etal. Perspect.
Plant Ecol. Evol. Syst. 12,
183–191; 2010).
Government and industry
sustainability initiatives akin to
those run by the World Cocoa
Foundation (see go.nature.
com/uj9nfh) could contribute
to cocoa-pollination research
and advise farmers on how best
to meet the world’s increasing
demand for chocolate.
Thomas C. Wanger* University
of Göttingen, Germany.
tomcwanger@gmail.com
*On behalf of 4 correspondents (see
go.nature.com/wh86eh for full list).
criteria (see go.nature.com/
lbrng2). Scopus includes only 726
of these journals (15%); regional
journals are not eligible (see also
go.nature.com/laywal).
That leaves 4,156 journals
whose impact is hidden
from Scopus. If we assume
conservatively that each of these
publishes only 20 articles per
year by South American authors,
then at least 83,120 articles are
being overlooked annually.
The commercial databases
should close this coverage gap
to properly reflect the impact of
research in South America.
Juan Pablo Alperin Stanford
University, California, USA.
juan@alperin.ca
Graduate admissions
test has some merit
We would like to clarify a
couple of points raised by Casey
Miller and Keivan Stassun
in their criticism of the US
Graduate Record Examination
(GRE) for selection of graduate
students (Nature 510, 303–304;
2014).
As documented in a meta-
analysis by independent
researchers, the GRE predicts
more than just first-year
graduate grades: it also predicts
higher-degree attainment,
time to complete, research
productivity and citation counts
(see N.R.Kuncel etal. Psychol.
Bull. 127, 162–181; 2001).
And although we acknowledge
that the GRE “reflects certain
demographic characteristics
of test-takers”, we reject any
implication that this is a fault in
the test: rather, test scores reflect
the reality that more educational
resources are available to students
from wealthier families.
We agree that graduate
admissions should be based on
multiple sources of information,
including standardized test
scores, undergraduate grades,
diligence and non-cognitive
factors such as ‘grit’.
Brent Bridgeman, David Payne,
Jacqueline Briel Educational
Testing Service, Princeton, New
Jersey, USA.
bbridgeman@ets.org
10 JULY 2014 | VOL 511 | NATURE | 155
© 2014 Macmillan Publishers Limited. All rights reserved
... Such initiatives primarily aim to both mitigate climate change impacts by preserving tropical rainforest, and to improve the livelihood of small-scale cocoa famers, which contribute 90% of the global cocoa production (Donald, 2004;Gockowski and Sonwa, 2011;Läderach et al., 2013;Schroth et al., 2017;WCF, 2018). While these sustainability initiatives promote sophisticated breeding technologies for climate-resistant varieties (MARS, 2018a) and improvements in fertilizer use (MARS, 2018b), they largely neglect alternative approaches such as enhancing pollination to improve cocoa yields sustainably (Young, 1982;Falque et al., 1995;Groeneveld et al., 2010;Wanger et al., 2014;Forbes and Northfield, 2017;Toledo-Hernández et al., 2017). ...
... Cocoa is a cross-pollinated plant that highly depends on specialized insects for successful pollination (Entwistle, 1972;Young, 1986;Toledo-Hernández et al., 2017). Pollen limitation, as less that 10% of flowers in a tree are successfully pollinated in natural conditions, appears to be a major factor to improve yields in Indonesia (Groeneveld et al., 2010;Wanger et al., 2014;Toledo-Hernández et al., 2017). In experiments in Ivory Coast, increased pollen deposition rates on the style enhanced the number of seeds per fruit (Falque et al., 1995). ...
... forest conservation) and farm management (e.g. shade canopy cover) practices for improving pollinator habitats can increase pollination rates, pollen deposition, and improve fruit set (Young, 1982;Wanger et al., 2014;Forbes and Northfield, 2017;Toledo-Hernández et al., 2017). ...
Hand pollination, not pesticides or fertilizers, increases cocoa yields and farmer income
Article
  • Aug 2020
  • AGR ECOSYST ENVIRON
Increasing demand for cocoa and climate-related yield declines have sparked a multi-stakeholder debate on cocoa production strategies. Agrochemical inputs and pollination enhancement through hand pollination are two strategies to increase yields. Here, we test both strategies with field experiments in Indonesia. We show that even partial hand pollination (13% of easily accessible flowers/tree), and not fertilizers or insecticides, increases yield/tree by 51%. The more laborious 100% hand pollination of the entire tree increases yield/tree by 161%, and farmer's annual net income from 994 USD/ha up to 1,677 USD/ha, or 69% in the study area, after accounting for farm operational, hand pollination labor, and opportunity costs. Thus, intensifying cocoa pollination appears to be a potential solution for closing cocoa yield gaps and should be considered in the current industry-led discussion of designing farms for mitigation of climate change.
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... Cocoa bean (Theobroma cacao L.) and its derivatives are widely used as important materials on food and other industries because it contains theobromine (Martínez-Pinilla et al., 2015). The global trade in cocoa is worth US$10 billion per year (Wanger et al., 2014). Indonesia is the third largest global cocoa producer with a total production of 0.59 million tons (Dirjenbun, 2016). ...
... There are numerous studies reporting the impact of rainfall and temperature on vegetative growth, flowering, pollination and bean production in cocoa (De Almeida and Valle, 2007;Omolaja et al., 2009;Adjaloo et al., 2012;Läderach et al., 2013;Afoakwa, 2014;Wanger et al., 2014;Teixeira et al., 2015;Towaha and Wardiana, 2015;Schroth et al., 2016). The rainfall and temperature are also utilized to predict crop production (Santosa et al., 2011;Purwanto and Santosa, 2016;Irfanda and Santosa, 2016). ...
... Unlike general problems faced in cocoa production by increasing temperature and shortage of rainfall, the fluctuation on temperature and rainfall became prominent in this study. Therefore, generic tools to improve production stability could include enhanced number of shade tree that produce more pollen as pollinator rewards, creating micro climate stability, and providing shade trees (Wanger et al., 2014;Schroth et al., 2016;Medina and Laliberte, 2017). ...
Cocoa Production Stability in Relation to Changing Rainfall and Temperature in East Java, Indonesia
Article
  • Feb 2018
Climate change as indicated by rising temperature and changing rainfall pattern has been known to affect cacao production in many production countries. However, studies on the effects of rainfall and temperature variability on the cacao production are rarely reported in Indonesia. Hence, the objective of this study is to evaluate the stability of cocoa production in relation to rainfall and temperature variability in order to develop sustainable production under climate change scenario. Research was conducted at a state owned company in Jember District, East Java, Indonesia from February to June 2015. Production and climatic data of 2010-2015 were evaluated using simple regression and correlation analysis. Results revealed that productivity fluctuated among months and among years. However, the fluctuation among months (s2 = 117.076) was lower than among years (s2 = 311.225). Rainfall and temperature showed variability among months and among years; and the fluctuation among months was lower in both rainfall and temperature. Rainfall at one to four months before harvest correlated with production (r=0.400-0.671; P= 0.000 to 0.001) and temperature at two to four months before harvest determined cocoa production (r=0.371-0.412; P=0.001-0.003). High monthly cocoa production coincided with decreasing temperature and rainfall for 4 to 5 months during pod development. The presented study implies that both short and long term strategies should be implemented under climatic variability to sustain cocoa production. It is recommended to apply production technology to stabilize micro climate temperature and to minimize the impact of high rainfall such as shade plant and canopy manipulation.
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... For example, yield gaps in small-scale agricultural systems can be reduced by enhancing pollination services (Garibaldi et al., 2016). Simple management improvements such as the addition of shade trees can have positive effects on both pollination and yield while also likely reducing climate risks (Wanger et al., 2014). Indeed, pollination success rather than nutrient limitation determines cocoa fruit set and yield in Indonesia (Groeneveld et al., 2010). ...
... However, these programs may fail in the long term if the necessary practices, such as shade tree management, to buffer climate impacts are not implemented, or if the costs of adopting such strategies exceed the overall farm profit (Leakey, 2014). Thus, cost effective farm-based management adaptations to counteract climatic risks, to reduce yield gaps, and to secure farm income are urgently needed (Wanger et al., 2014;Schroth et al., 2016). ...
Neglected pollinators: Can enhanced pollination services improve cocoa yields? A review
Article
  • Sep 2017
  • AGR ECOSYST ENVIRON
The negative effects of climate change on cocoa production are often enhanced through agricultural intensification, while research institutions and enterprises try to minimize yield gaps with production strategies mitigating climate risk. Ecological intensification is such a production strategy, whereby yield increase is promoted through reduced agrochemical inputs and increased regulating ecosystem services such as pollination. However, we still know little about cocoa pollination ecology and services, although they appear to be key to understand yield functions. Here, we provide an extensive literature review on cocoa pollination focusing on three main aspects: non-plant (external) and plant regulated (internal) factors affecting pollination, pollinator agents, and ecological intensification management for enhancing pollination success and yield. Pollination services by many arthropod groups such as ants, bees, and parasitic wasps, and not only ceratopogonids, may be a way to increase cocoa productivity and secure smallholders income, but their role is unknown. Several environmental and socioeconomic factors can blur potential pollination benefits. Current knowledge gaps preclude our understanding of how to (i) identify the major pollinator species, (ii) disentangle the direct or indirect role of ants in pollination, (iii) design effective habitat improvements for pollination (by litter and shade management), and (iv) quantify the yield gaps due to pollination limitation. Optimizing cocoa pollination alone appears to be a powerful ecological tool to increase the yield of smallholders, but experimental research is required to validate these results in a realistic setting. In general, industry, governments and smallholders need to develop more joined efforts to ecological production strategies. In particular, farm-base management innovations based on robust scientific evidence must be designed to meet the increasing demand for chocolate and to mitigate cocoa yield gaps. This review suggests that diversified systems and associated ecosystem services, such as pollination, can help to achieve such goals.
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... Demand for cocoa, the third largest trade commodity globally (1), is increasing in China, Russia, India, and Brazil by 2.5% per year (2), while production has declined by an average 1.5% annually for the past decade (3). Climate change is further exacerbating this trend through increasing drought events and pest outbreaks diminishing yields (4). The three major cocoa producing countries are Ivory Coast, Ghana, and Indonesia. ...
Cocoa pollination, biodiversity-friendly production, and the global market
Preprint
Full-text available
  • Dec 2021
Production of cocoa, the third largest trade commodity globally has experienced climate related yield stagnation since 2016, forcing farmers to expand production in forested habitats and to shift from nature friendly agroforestry systems to intensive monocultures. The goal for future large-scale cocoa production combines high yields with biodiversity friendly management into a climate adapted smart agroforestry system (SAS). As pollination limitation is a key driver of global production, we use data of more than 150,000 cocoa farms and results of hand pollination experiments to show that manually enhancing cocoa pollination (hereafter manual pollination) can produce SAS. Manual pollination can triple farm yields and double farmers annual profit in the major producer countries Ivory Coast, Ghana, and Indonesia, and can increase global cocoa supplies by up to 13%. We propose a win win scenario to mitigate negative long term price and socioeconomic effects, whereby manual pollination compensates only for yield losses resulting from climate and disease related decreases in production area and conversion of monocultures into agroforestry systems. Our results highlight that yields in biodiversity friendly and climate adapted SAS can be similar to yields currently only achieved in monocultures. Adoption of manual pollination could be achieved through wider implementation of ecocertification standards, carbon markets, and zero deforestation pledges.
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... Cocoa (Theobroma cacao L.) is the third largest export crop commodity worldwide (Donald, 2004), but faces yield declines associated with limited resilience to climate change (Wanger et al., 2014). Increasing temperatures, prolonged drought, and increased pest and disease outbreaks are affecting cocoa yields, jeopardizing the livelihood of small-scale farmers in the main producing regions of West-Africa (Läderach et al., 2013;Schroth et al., 2016), South East Asia (Bunn et al., 2017) and South America (Gateau-Rey et al., 2018). ...
Landscape and farm-level management for conservation of potential pollinators in Indonesian cocoa agroforests
Article
  • Apr 2021
  • BIOL CONSERV
Cocoa (Theobroma cacao L.), a major commodity globally, depends on insects for pollination. However, the cocoa pollinator identity is largely unknown and there are important knowledge gaps regarding landscape and farm-level management driving pollinators. Here we analyzed flower visitation with two approaches to quantify how landscape and farm-level factors affect potential pollinators (flower visitors) of cocoa in Central Sulawesi, Indonesia. In the first approach (landscape and farm-level) we selected 18 farms and focused on the relative importance of distance to forest (m), potential-pollinator habitats surrounding the farm (i.e. secondary forests and cocoa agroforests [%]), canopy cover (%), leaf-litter amount (kg/m²), and cocoa flower abundance for flower visitors. In the second approach (experimental farm management) we manipulated leaf-litter in 24 farms, because high leaf-litter is suggested to enhance flower visitors. We found that ants and Diptera were the most common flower visitors, and although previous studies suggest ceratopogonids as main cocoa pollinators, none were captured in this study. In the landscape and farm-level approach, potential-pollinator habitats surrounding the farm, and increased canopy cover enhanced ant and Diptera abundance, whereas distance to forest had no effect. In the experimental farm management approach, potential-pollinator habitats surrounding the farm rather than leaf-litter manipulation increased Diptera and ant abundance. In summary conservation of forests and agroforests surrounding the farm, maintaining canopy cover and minimum leaf-litter enhance cocoa flower visitors. Thus, farms with shade trees embedded in a biodiversity-friendly landscape are important for conservation of potential pollinators and pollination services and, thereby, promotion of sustainable cocoa.
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... vulnerable to climate change(Wanger, 2014): altered weather patterns put these environments at increased risk of prolonged drought during dry seasons (Intergovernmental Panel on Climate Change, 2014). Our findings indicate that dry periods reduce cocoa midge abundance acutely, but more information is needed to extrapolate the implications were the regions under study to suffer multiple successive extreme dry seasons. ...
The significance of climate in the pollinator dynamics of a tropical agroforestry system
Article
Full-text available
  • Nov 2017
  • AGR ECOSYST ENVIRON
Even though many globally important tropical agroforestry crops are partially or completely dependent on insect pollination, the conditions influencing pollinator abundance in these systems are often incompletely understood. This is particularly the case for cocoa midges (Diptera: Ceratopogonidae), which are essential for cocoa pollination and thus yield, but agro-ecological management frequently neglects them. We report the first assessment of cocoa midge population dynamics from two Caribbean countries across a full year, and relate this to seasonal climate variables. We used static suction traps along transects to sample insects monthly, from six cocoa farms across three Caribbean islands, with a particular focus on known pollinators of cocoa. A total of over 87,000 insects were captured, including more than 1800 cocoa midges. Midges were present in all months of the survey and on all sites, but typically comprised less than 2% of the total insects caught. At least twelve different species of cocoa midges were identified from this survey. The previous month's rainfall positively predicted cocoa midge absolute abundance and further analysis also revealed a relationship between rainfall and relative midge abundance. In particular, during drought periods, midge numbers were very low, consistent with their larval ecology. Humidity and mean daily maximum and minimum temperatures did not relate to midge abundance. Rainfall negatively influenced the Shannon-Weaver index. The findings highlight the possible threat of droughts to cocoa pollination services and the importance of proactive farm management to support them.
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Effects of Ecosystem Services Provided by Birds and Bats in Smallholder Cacao Plantations of Central Sulawesi: Summary of research results, management recommendations and farmer workshops from cacao agroforestry landscapes in Indonesia
Book
Full-text available
  • Jan 2018
This book is based on close and multi-year communication between ecologists and local cacao farmers and can therefore serve as a valuable tool to build a bridge of communications between farmers and scientists about ecosystems, biodiversity and land use strategies. As described in the book, birds and bats can make an economically beneficial contribution to cacao yield in Central Sulawesi and might therefore represent a valuable alternative to intensive farming practices, which impair the health and sustainability of cacao agroforestry systems. Thus, the findings and results presented in this book can help farmers to consider more biodiversity-friendly practices in the management of their farms
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Cocoa Production: Monocultures are Not the Solution to Climate Adaptation - - Response to Abdulai et al. 2017
Article
  • Dec 2017
Cocoa is a major trade commodity that is seeing increasing demand, but also climate-related yield declines1 . There has been an ongoing discussion whether both, the effective adaptation of plantations to climate change and a long term increase of cocoa yields, can only be achieved with shaded agroforestry or also with full-sun monocultures2 . Abdulai et al. 3 investigated the climate adaptation potential of full-sun cocoa monocultures and shaded agroforestry in Ghana West Africa. This article is protected by copyright. All rights reserved.
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Spatially resolved transcriptomics and beyond
Article
Full-text available
  • Dec 2014
Considerable progress in sequencing technologies makes it now possible to study the genomic and transcriptomic landscape of single cells. However, to better understand the complexity of multicellular organisms, we must devise ways to perform high-throughput measurements while preserving spatial information about the tissue context or subcellular localization of analysed nucleic acids. In this Innovation article, we summarize pioneering technologies that enable spatially resolved transcriptomics and discuss how these methods have the potential to extend beyond transcriptomics to encompass spatially resolved genomics, proteomics and possibly other omic disciplines.
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Predicting the future climatic suitability for cocoa farming of the world's leading producer countries, Ghana and Côte d'Ivoire
Article
  • Aug 2013
Ghana and Côte d’Ivoire are the world’s leading cocoa (Thebroma cacao) producing countries; together they produce 53 % of the world’s cocoa. Cocoa contributes 7.5 % of the Gross Domestic Product (GDP) of Côte d’Ivoire and 3.4 % of that of Ghana and is an important cash crop for the rural population in the forest zones of these countries. If progressive climate change affected the climatic suitability for cocoa in West Africa, this would have implications for global cocoa output as well as the national economies and farmer livelihoods, with potential repercussions for forests and natural habitat as cocoa growing regions expand, shrink or shift. The objective of this paper is to present future climate scenarios for the main cocoa growing regions of Ghana and Côte d’Ivoire and to predict their impact on the relative suitability of these regions for growing cocoa. These analyses are intended to support the respective countries and supply chain actors in developing strategies for reducing the vulnerability of the cocoa sector to climate change. Based on the current distribution of cocoa growing areas and climate change predictions from 19 Global Circulation Models, we predict changes in relative climatic suitability for cocoa for 2050 using an adapted MAXENT model. According to the model, some current cocoa producing areas will become unsuitable (Lagunes and Sud-Comoe in Côte d’Ivoire) requiring crop change, while other areas will require adaptations in agronomic management, and in yet others the climatic suitability for growing cocoa will increase (Kwahu Plateu in Ghana and southwestern Côte d’Ivoire). We recommend the development of site-specific strategies to reduce the vulnerability of cocoa farmers and the sector to future climate change.
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Experimental evidence for stronger cacao yield limitation by pollination than by plant resources
Article
  • Aug 2010
  • PERSPECT PLANT ECOL
Both pollination and resource limitation may cause low fruit:flower ratios in plants, but pollen and resource limitation have never been contrasted in commercially important crop species. Here we experimentally investigated the relative effect of pollen limitation and resource limitation in Theobroma cacao. In Central Sulawesi, Indonesia, we applied different relative levels of hand pollination (10%, 40%, 70% and 100% of available flowers up to 2 m height) to mature cacao trees in two separate experiments encompassing (1) different light (shade roofs) and nitrogen (fertilizer application) treatments, and (2) water availability (throughfall displacement) treatments. None of the resource availability treatments had a significant effect, while number of mature pods and yield increased non-linearly with pollination intensity up to 200% of current yield levels. The largest benefits were reached by increasing pollination from 10% to 40%, with non-significant increases beyond that level. Despite an increase of fruit abortion with pollination intensity, T. cacao yield is determined, at least on the short term, by the number of flowers pollinated. This suggests pollination deficit in crops can be very large and that a better knowledge of pollen and resource limitation to devise adequate pollinator management strategies may be critical for increasing production.
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