Biodiversity on Earth, including the diversity of species, genetic diversity within species, and the diversity of ecosystems, is the basis of life of all organisms, including humans. Fundamental processes depend on biodiversity, such as plant growth and the stability of material cycles. However, biological diversity is decreasing continuously. According to researchers, this loss has meanwhile reached an alarming extent. For this reason, numerous scientific studies and experiments cover the importance of biodiversity to the functioning of ecosystems and their use for humans.

Species Loss Has Direct Consequences for Humans

One of the biggest and longest projects on biodiversity is the Jena Experiment that was funded by the German Research Foundation from 2002 to 2019 (DFG; research groups FOR 456 and FOR 1451) and coordinated by Jena University. In the experiment researchers from different scientific institutions studied the effects of biodiversity on grassland. Through comprehensive quantification of cycles of major chemical elements and investigation of above-ground and underground processes, they determined basic mechanisms. Professor Wolfgang Wilcke, Head of the Geomorphology and Soil Science Group of KIT's Institute of Geography and Geoecology (IFGG), and Dr. Sophia Leimer, scientist and member of this group, participated in the experiment and studied the relationship between plant diversity and the nitrogen and phosphorus cycle.

"The findings of the Jena Experiment confirm that current species loss has directly consequences for humankind," Wilcke says. "As a result, functions of nature that may apparently be taken for granted break off." According to the geoecologist, examples are the production of biomass for food, fabrics, construction materials, and fuels as well as water and nutrient cycles. Their changes have severe impacts, such as floods, drought, or groundwater pollution. "To stop this development and to protect species diversity, further research and practical measures on all levels are needed, from the individual consumer to national governments to international bodies," Wilcke continues.

Significance of Biodiversity Can Only Be Determined by Interdisciplinary Research

In a series of three publications in Nature Ecology & Evolution, the Jena consortium published major results between 2018 and 2020: The more ecosystem functions, such as a closed nutrient cycle, and resulting ecosystem services (e.g. biomass production) are to be achieved, the more plant species are needed, the scientists say.

Together with the BioDIV Experiment in the USA, the Jena consortium found that the results of artificial experiments, in which mixes of plant species were usually composed randomly, are stable and may be transferred to the natural world.

In its most recent publication, the Jena Experiment concludes that ecosystem functions and services cannot only be predicted from the properties of plants. It is rather necessary to consider the entire complexity of biotic and abiotic interactions of an ecosystem, i.e. all interactions in the living and non-living nature.

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Journal References:

1. Fons van der Plas, Thomas Schröder-Georgi, Alexandra Weigelt, Kathryn Barry, Sebastian Meyer, Adriana Alzate, Romain L. Barnard, Nina Buchmann, Hans de Kroon, Anne Ebeling, Nico Eisenhauer, Christof Engels, Markus Fischer, Gerd Gleixner, Anke Hildebrandt, Eva Koller-France, Sophia Leimer, Alexandru Milcu, Liesje Mommer, Pascal A. Niklaus, Yvonne Oelmann, Christiane Roscher, Christoph Scherber, Michael Scherer-Lorenzen, Stefan Scheu, Bernhard Schmid, Ernst-Detlef Schulze, Vicky Temperton, Teja Tscharntke, Winfried Voigt, Wolfgang Weisser, Wolfgang Wilcke, Christian Wirth. Plant traits alone are poor predictors of ecosystem properties and long-term ecosystem functioning. Nature Ecology & Evolution, 2020; DOI: 10.1038/s41559-020-01316-9
2. Malte Jochum, Markus Fischer, Forest Isbell, Christiane Roscher, Fons van der Plas, Steffen Boch, Gerhard Boenisch, Nina Buchmann, Jane A. Catford, Jeannine Cavender-Bares, Anne Ebeling, Nico Eisenhauer, Gerd Gleixner, Norbert Hölzel, Jens Kattge, Valentin H. Klaus, Till Kleinebecker, Markus Lange, Gaëtane Le Provost, Sebastian T. Meyer, Rafael Molina-Venegas, Liesje Mommer, Yvonne Oelmann, Caterina Penone, Daniel Prati, Peter B. Reich, Abiel Rindisbacher, Deborah Schäfer, Stefan Scheu, Bernhard Schmid, David Tilman, Teja Tscharntke, Anja Vogel, Cameron Wagg, Alexandra Weigelt, Wolfgang W. Weisser, Wolfgang Wilcke, Peter Manning. The results of biodiversity–ecosystem functioning experiments are realistic. Nature Ecology & Evolution, 2020; DOI: 10.1038/s41559-020-1280-9
3. Sebastian T. Meyer, Robert Ptacnik, Helmut Hillebrand, Holger Bessler, Nina Buchmann, Anne Ebeling, Nico Eisenhauer, Christof Engels, Markus Fischer, Stefan Halle, Alexandra-Maria Klein, Yvonne Oelmann, Christiane Roscher, Tanja Rottstock, Christoph Scherber, Stefan Scheu, Bernhard Schmid, Ernst-Detlef Schulze, Vicky M. Temperton, Teja Tscharntke, Winfried Voigt, Alexandra Weigelt, Wolfgang Wilcke, Wolfgang W. Weisser. Biodiversity–multifunctionality relationships depend on identity and number of measured functions. Nature Ecology & Evolution, 2017; 2 (1): 44 DOI: 10.1038/s41559-017-0391-4