Research Projects

Long-term biodiversity experiments have shown that the strength of the mostly positive biodiversity effect on ecosystem functioning increases over time. With the highly interdisciplinary work in the Jena Experiment, we could empirically demonstrate that community assembly, biotic interactions, and eco-evolutionary processes are intertwined and determine long-term biodiversity-ecosystem functioning relationships.

Following on from these mechanistic insights, in the second phase of the DFD Research Unit in the Jena Experiment (FOR-5000/2 from 2024 to 2027), we are now focusing on the biological determinants of ecosystem stability, including temporal stability using unique long-term time series and stability in response to extreme climate events such as droughts, floods, heat waves, and severe frosts. The main hypothesis is that ecosystem stability is highest in plant communities with high biodiversity and that the relationships between biodiversity and stability increase over time, reflecting a broad range of ecological complementarity.

In the current Research Unit, a total of eleven subprojects (SPs) are working together on three different leading research platforms: in the field (Main Experiment), in the iDiv Ecotron (ResCUE Experiment), or in microcosm experiments (e.g. DrY Experiment). Here, the SPs are organised into three closely linked main research areas, all of which aim to investigate long-term relationships between biodiversity and the stability of various ecosystem functions. The subprojects in area (1) ‘Plant stress resistance and physiological stability’ mainly focus on the interactions between plants and their abiotic and biotic environment; the subprojects in area (2) ‘Soil stability and nutrient dynamics’ investigate the effects of plant diversity on the stability of ecosystem functions and soil nutrient dynamics; while the subprojects in area (3) ‘Stability of multitrophic communities and food webs’ focus primarily on communities and functions determined by higher trophic levels (microbes to invertebrates) both above and below ground. Ultimately, the data and information from all sub-projects and research platforms will be integrated into a comprehensive synthesis.

Contact: Nico Eisenhauer

More information: The Jena Experiment

MyDiv is an open experimental platform for tree diversity experiments. It is located at the UFZ field research station in Bad Lauchstädt. MyDiv investigates the role of mycorrhiza and its different types in tree diversity-ecosystem functioning relationships and belowground carbon flow. We expect tree species communities of different mycorrhizal types to act complementarily compared to communities of only one type and that this effect is even stronger in more diverse tree communities. Further, tree communities with diverse mycorrhizal associations may foster more diverse soil animal communities. On 80 plots, we planted tree species in monocultures, 2-species, and 4-species mixtures in March 2015. At each of the tree diversity levels, we established communities with only ectomycorrhiza, only arbuscular mycorrhiza or mixtures of both mycorrhizal types.

TreeDivNet is a global network of tree biodiversity experiments. The network comprises several experiments in different parts of the world and forms the largest project on ecosystem research worldwide. In total, over 1 Million trees were planted in the 32 experiments. MyDiv is a member of TreeDivNet and regularly samples its site in the framework of large global campaigns. It also contributes data to large synthesis studies.

Contact: Olga Ferlian

More information: MyDiv

The iDiv Ecotron is a mesocosm facility that provides infrastructure for experimental manipulation of biotic communities (aboveground and belowground) and abiotic environments (e.g. precipitation, nutrients) in terrestrial ecosystems. Established in 2017, based on a collaboration between UFZ and iDiv, the iDiv Ecotron has hosted multiple unique experiments and is now a key feature of many current project proposals by iDiv members and beyond. Each of 24 EcoUnits can be divided into four subunits allowing for 96 experimental units with either intact soil monolith cores or a filled soil profile. The main objective of the iDiv Ecotron is to evaluate the role of multitrophic above-belowground diversity in food webs and study the consequences for multiple ecosystem functions. We welcome proposals from scientists who wish to test hypotheses in various plant and animal systems.

For feedback on feasibility and match of interests on potential proposals, please contact Nico Eisenhauer.

All proposals are reviewed by the Ecotron Board.

In the framework of the TreeDì international research training group, we are studying the effects of tree-tree and tree-shrub interactions on soil biodiversity-ecosystem functioning within the BEF-China experimental platform. By studying tree functional dissimilarity, we aim to understand the mechanisms behind tree diversity’s effects on soil ecosystem functioning. In more detail, we investigate the effects of tree-tree and tree-shrub functional dissimilarity and local neighbourhood diversity on soil functioning. Therefore, soil nitrogen and carbon dynamics modelling is used, as well as measurements of microbial community composition and functions.

Contact: Nico Eisenhauer, Simone Cesarz

The Global Change Experimental Facility (GCEF) is a large-scale field experiment aimed at understanding the impacts of climate change on ecosystem processes under various land-use scenarios. Established in 2014 at the UFZ field research station, the experiment consists of 50 plots, half of which are subjected to simulated future climate conditions anticipated for Central Germany.

These conditions involve higher temperatures and altered rainfall patterns, with increased spring and autumn precipitation and reduced summer rainfall. Climate conditions are carefully controlled using automated roofs and side panels that close during rain or at night, along with an integrated irrigation system. The experiment covers a range of land-use practices, including conventional farming, organic farming, intensive grassland management, extensive meadows, and extensive sheep grazing.

Each plot is managed according to typical agricultural practices, such as standard crop rotations, fertilisation, and the use of agrochemicals where necessary. The large plot sizes and realistic management techniques ensure that the findings are highly applicable to real-world agricultural settings. The primary goal of the GCEF experiment is to explore how these projected climate conditions, when combined with different land-use methods, will influence ecosystem processes. The insights gained from this research are intended to inform strategies for sustainable land management in the face of a changing climate.

More information: Global Change Experimental Facility

Nutrient Network (NutNet) is an international research project focused on exploring the effects of nutrient enrichment on grassland ecosystems. Established in 2015 at the UFZ field research station in Bad Lauchstädt, this experiment includes several plots where nitrogen, phosphate, and potassium sulfate fertilisers are applied in varying combinations to study the impact of these nutrients on ecosystem functions. This setup allows researchers to investigate the interactions between different nutrients and their effects on both aboveground and belowground processes. This involves annual assessments of plant community composition, aboveground biomass, soil characteristics, and light availability. These data are crucial for understanding how nutrient inputs influence grassland ecosystems over time. The NutNet experiment follows a standardised methodology applied across more than 130 sites globally, ensuring that data collected at Bad Lauchstädt is comparable with other research locations worldwide.

As a part of this extensive global network, NutNet is dedicated to providing a deeper understanding of how human activities, such as fertilisation and land use change, impact grassland ecosystems across different regions. The network aims to unravel the complex relationships between nutrient availability, ecosystem productivity, and biodiversity. By participating in this collaborative effort, NutNet supports the development of strategies to mitigate biodiversity loss and promote sustainable ecosystem management.

More information: Nutrient Network

Drought-Net is a global field experiment designed to understand the effects of drought and nutrient addition on terrestrial ecosystems. Established in 2016 at the UFZ field research station in Bad Lauchstädt, the experiment features 25 plots where 55% of natural rainfall is drained to simulate extreme drought conditions. Additionally, some plots receive full NPK fertilisation, enabling the exploration of the interaction between drought and nutrient addition to assess the combined effects of these stressors. The project investigates both aboveground and belowground ecosystem processes, with annual measurements of plant functional composition, aboveground biomass, microbial respiration and biomass, as well as soil water content.

As part of a larger global network, Drought-Net contributes to a comprehensive analysis of ecosystem sensitivity to drought events. This network exposes diverse terrestrial ecosystems worldwide to extreme drought scenarios expected to occur only once every 100 years. The ultimate goal is to identify and understand the mechanisms driving the varied responses of ecosystems to drought, thereby enhancing our ability to predict and mitigate the impacts of climate change.

More information: Drought-Net

The Bug-Network (BugNet) is a global collaborative research initiative led by researchers from the University of Bern, Switzerland, to study the impact of invertebrate herbivores and pathogenic fungi on plant communities and ecosystems. Arthropod herbivores, molluscs, and fungal pathogens will be excluded from different plots to study their impact. Our experimental site, “BadBug”, was established in late 2021 at the field research station of the Helmholtz-Centre for Environmental Research in Bad Lauchstädt, Germany. BadBug is jointly led by Dr. Lotte Korell (UFZ) and Prof. Dr. Malte Jochum (University of Würzburg), with support by Dr. Harald Auge, Dr. Martin Schädler, and Prof. Nico Eisenhauer. At BadBug, we aim to assess the responses of the plant community, arthropod community, and soil conditions to the experimental treatments. From 2023 a PhD student, Ioannis Constantinou, has been employed for this project.

Contact: Malte Jochum, Nico Eisenhauer

Soil organisms and ecosystem functions are poorly represented in macroecological analysis, with extensive geographic and thematic gaps undermining our assessment of soil ecosystems worldwide. In this context, in 2018, an international group of researchers decided to establish the first global soil biodiversity observation network to not only reduce the geographic gaps in knowledge but also to support the development of new monitoring systems and assess trends in soil biodiversity and ecosystem functions.

Constituted as the global Soil Biodiversity Observation Network (Soil BON), this group works in partnership with the Global Soil Biodiversity Initiative (GSBI) and other global and regional partners to make available the soil biological and ecosystem observations needed to ensure living soil resources are sustainably conserved and managed and can support essential human needs. Soil BON partners represent a range of stakeholders, including researchers, educators, and policy advisors from academic, governmental, and private sectors. The goal is to further connect multinational partners and initiatives worldwide to understand soil biodiversity, document how it changes, how these changes affect people who rely on soil living resources for their well-being and livelihoods, and how sustainable use of ecosystems can safeguard soil biodiversity.

With support from iDiv, several sampling campaigns are already programmed, and collaborations with other global initiatives (Global Crop Microbiome, Biodesert, iSBio, among others) will improve our scope and enlarge our capacity to understand global soil systems and their contribution to biogeochemical cycles.

Contact: Soil BON Team

In collaboration with the European Soil Data Centre from the Joint Research Center, iDiv members from different institutions (FUB, UFZ, UL) started a project to assess European soil functions. This project emerged from the soil sampling campaign within the Land Use and Coverage Area frame Survey (LUCAS) supported by the Eurostat and aims to process ~1000 soil samples collected across all European countries.

Together with the Joint Research Center, we will be able to assess not only the patterns of soil ecosystem functions but also their drivers and the links to biodiversity. This significant effort from iDiv and the Joint Research Center will allow a deeper view of belowground dynamics in Europe for the first time and assess the impacts of human activities on soil systems.

Contact: Romy Zeiss

The iSBio Consortium was created in 2018 in collaboration with theTeaComposition network. It consists of 106 institutions distributed across 35 countries on six continents and aims to establish a long lasting global collaboration among partners to study soil macro-ecological biodiversitypatterns and how these relate to important soil functions, such as litter decomposition, soil carbon sequestration, aggregate stability, and nutrient cycling. With its global perspective, it focuses on (i) understanding the macro-ecological patterns related to soil biodiversity and ecosystem function relations, (ii) supporting global soil biodiversity distribution models, and (iii) publishing scientific papers and reports and disseminate soil biodiversity data in global databases.

Contact: Guillaume Patoine, Carlos Guerra