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How tree extinction affects the food web

German Research Foundation approves international research group headed by biologist Alexandra-Maria Klein

Freiburg, Jun 02, 2022

How tree extinction affects the food web

The Blue Golden Wasp Trichrysis cyanea is a foraging parasite in spider-hunting digger wasps, which use trap nests but also bee houses in China and Germany and are buiding an important link in food webs. Photo: Felix Fornoff

The German Research Foundation (DFG) has approved the Research Group 5281 “Multitrophic Interactions in a Forest Biodiversity Experiment in China,” or in short MultiTroph, headed by Prof. Dr. Alexandra-Maria Klein from the Institute of Earth and Environmental Sciences at the University of Freiburg. The goal is to investigate the interactions between tree extinction and food webs in the forests. Klein is coordinating eight projects of the international research group on the world’s largest forest biodiversity experiment in China. Scientists from various German and Austrian universities are working closely with the Chinese Academy of Sciences and Beijing Forestry University in China. The team will receive funding of around three million Euros for four years in the first project phase starting in October 2022.

How many tree species does a forest need?

“We aim to understand what happens to the food webs when tree species become extinct or are introduced to the forest ecosystem,” Klein explains. “How many tree species does a forest need to function? What characteristics do these tree species need so that the forest can cope with climate change? When do food webs collapse or shift so much that forest ecosystem services are negatively affected?”

Interdisciplinary research

Researchers from different disciplines are collaborating in MultiTroph. Experts in soil science, botany, molecular biology, ecological networks, animal ecology and nature conservation are working on eight projects with different focal points.

The scientists are investigating deadwood degradation in the Chinese forest area. They are also analyzing the effects of trophic interactions, tree diversity and soil erosion on the stoichiometry of soil and plants. Another focus is the study of food webs between plants, herbivores, and predatory insects, such as linking food webs between bees and flowers, and wasps and prey in nesting structures. Furthermore, the research team is interested in trophic interactions at different stages of tree regeneration. The partial aspects will be combined to form a large food web.

Supplementing research data on forest biodiversity

“We are convinced that our research group will critically supplement existing forest biodiversity research data and lead to a sound understanding of multi-trophic food webs in forests,” says Klein.

In addition to scientists from Freiburg, the project team consists of researchers from the University of Bayreuth, the Technical University of Darmstadt, the University of Göttingen, the Martin Luther University Halle-Wittenberg, the University of Hohenheim, the Kiel University, the University of Tübingen, the University of Würzburg, the Paris Lodron University Salzburg in Austria and the Pennsylvania State University in the US. On the Chinese side, scientists from the Chinese Academy of Sciences and Beijing Forestry University/China are collaborating.

Overview of facts:

  • Klein has headed the Chair of Nature Conservation and Landscape Ecology at the University of Freiburg since 2013. Her research focuses on bees and crop pollination and biodiversity restoration in agricultural landscapes.
  • Since 2015, Klein has been Vice President of the Ecological Society for Germany, Switzerland and Austria (GFÖ).
  • Klein is a member of the DFG Permanent Senate Commissions on Fundamental Issues of Biodiversity and the DFG Permanent Senate Commissions on Key Questions of Genetic Research and serves on several advisory boards for the State government in Baden-Württemberg.


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Prof. Dr. Alexandra-Maria Klein
Chair of Nature Conservation and Landscape Ecology
Institute of Earth and Environmental Sciences
University of Freiburg
Tel.: 0761/203-67770
Twitter: @naturealexk

Franziska Becker
Office of University and Science Communications
University of Freiburg
Tel.: 0761/203-54271