Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Coffee: better harvest thanks to biodiversity

05.02.2014
Bees, birds, and bats make a huge contribution to the higher yields produced by coffee farmers around Mount Kilimanjaro – an example of how biodiversity can pay off.

A lot of coffee is grown on Kilimanjaro, the East African massif almost 6000 meters high. The most traditional form of cultivation can be found in the gardens of the Chagga people: there the sun-shy coffee trees and many other crop plants thrive in the shade of banana trees and other tall trees.


A fine net keeps pollinators away from coffee blossoms. This is fairly detrimental to the quality of the coffee.

(Photo: Alice Classen)


If birds and bats are prevented by a net from feeding on pests on coffee trees, this lowers the yield.

(Photo: Alice Classen)

However, the majority of the coffee is grown on plantations. Although these also have many shade trees still, they are being chopped down in ever greater numbers. The reason for this is that “conventional coffees, which rely on shade, are increasingly being replaced by varieties that tolerate lots of sun and are more resistant to fungi,” explains Professor Ingolf Steffan-Dewenter, a tropical ecologist at the University of Würzburg's Biocenter.

The hope is that this crop intensification will lead to higher yields. However, it is possible that the harvest on the plantations will be no better in the end: the very fact that there will hardly be any shade trees left there will mean that the habitat may become scarce for animals that pollinate the coffee, eat pests, and thereby help to improve the yield.

Approach taken by the researchers

Steffan-Dewenter and his doctoral student Alice Classen therefore wanted to know what contribution bees, birds, bats, and other animals make to pollination and to biological pest control in the coffee fields. They also wanted to find out whether intensified farming has an impact on these free services provided by the ecosystem. They worked closely on this with teams from the Biodiversity and Climate Research Centre (Frankfurt/Main) and the Institute of Experimental Ecology at the University of Ulm.

The tropical experts conducted experiments in all three cultivation systems (Chagga gardens, shade plantations, and sun plantations) in twelve areas on the slopes of Mount Kilimanjaro in Tanzania. They used nets to deny animals access to the coffee blossoms or even to entire coffee trees. Then they examined, among other things, how the presence or absence of the “animal service providers” affects the quantity and quality of the harvest.

Role played by animals in coffee-growing

It was revealed that where birds and bats had access to the plants, there was almost a ten percent higher fruit set. “We believe that this is down to the fact that the animals destroy pests that would otherwise feed on the coffee plants,” says Julia Schmack (Frankfurt). This reduction in leaf damage probably leads to fewer coffee cherries falling from the tree before they are ripe.

Looking at pollination was also interesting. Bees and other insects should actually be redundant here, since the examined coffee variety, Coffea arabica, can also self-pollinate. Yet, the researchers found that if pollinators have access to the coffee blossoms, the cherries are around seven percent heavier, which signifies that the coffee is of higher quality.

“So, the effects of pollination and pest control complement each other perfectly; both are important for higher yields,” says Steffan-Dewenter: Birds and bats provide more cherries; bees and other pollinators ensure better quality.

Same effect with all cultivation systems

To the surprise of the researchers, intensified farming does not have a negative effect: the impact that the services provided by the animals had on the harvest was equally good in all three cultivation systems, even in the sun plantations.

“We put this down to the mosaic landscape structure on Mount Kilimanjaro with its gardens, forests, and grasslands,” says the doctoral student, Alice Classen. Given that much of the landscape is divided into small parcels, pollinators, birds, and bats could still find a sufficient habitat with nesting places and swarm out from there into the plantations.

Shaky foundations in sun plantations

“However, it is likely that these seemingly stable ecosystem services rest on shaky foundations in the sun plantations,” believe the Würzburg scientists. This is because they registered virtually only one type of visitor to the blossoms there: honey bees.

On the coffee blossoms in the Chagga gardens, on the other hand, they also sighted wild bees, hoverflies, and butterflies. So, if honey bee numbers were to fall, as they might in a year that is climatically unfavorable for these insects, this could reduce the harvest in the sun plantations.

Findings of a DFG research group

These findings have been published in the journal “Proceedings of the Royal Society B”. They have been produced by a research group that focuses on the ecosystems of Mount Kilimanjaro and is funded by the German Research Foundation (DFG).

Homepage of the DFG research group:
http://www.kilimanjaro.biozentrum.uni-wuerzburg.de
“Complementary ecosystem services provided by pest predators and pollinators increase quantity and quality of coffee yields.” Alice Classen, Marcell K. Peters, Stefan W. Ferger, Maria Helbig-Bonitz, Julia Schmack, Genevieve Maassen, Matthias Schleuning, Elisabeth K. V. Kalko, Katrin Böhning-Gaese, Ingolf Steffan-Dewenter, Proceedings of the Royal Society B, 2014, February 5, DOI 10.1098/rspb.2013.3148

Contact

Alice Classen, Department of Zoology III (Animal Ecology and Tropical Biology), Biocenter, University of Würzburg, T +49 (0)931 31-82793, alice.classen@stud-mail.uni-wuerzburg.de

Robert Emmerich | Universität Würzburg
Further information:
http://www.uni-wuerzburg.de
http://www.kilimanjaro.biozentrum.uni-wuerzburg.de

More articles from Agricultural and Forestry Science:

nachricht Microalgae food for honey bees
12.05.2020 | US Department of Agriculture - Agricultural Research Service

nachricht Global trade in soy has major implications for the climate
07.05.2020 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

New 5G switch provides 50 times more energy efficiency than currently exists

27.05.2020 | Information Technology

Return of the Blob: Surprise link found to edge turbulence in fusion plasma

27.05.2020 | Physics and Astronomy

Upwards with the “bubble shuttle”: How sea floor microbes get involved with methane reduction in the water column

27.05.2020 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>