Coordination Funds

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The previous phase of the Jena Experiment provided novel empirical evidence that ecological and evolutionary processes are intertwined in determining biodiversity-ecosystem functioning (BEF) relationships, and long-term experiments are key not only to gain a basic understanding of the relative importance as well as interactions of these processes but also to apply these concepts to better provisioning of ecosystem functions and stability. However, this prior research predominantly focused on the magnitude of various ecosystem functions, rather than on their stability, and mechanistic insights into biodiversity-stability relationships are especially lacking. It is thus key to continue developing a whole-ecosystem perspective in BEF research. In this interdisciplinary project, we propose to focus on the biodiversity drivers of ecosystem stability in the second phase of the Research Unit, including temporal stability using unique time series and stability in response to extreme climate events, such as drought, flooding, hot spells, and exceptional frost periods. The main hypothesis is that (multifunctional) stability is highest in high-diversity plots and biodiversity-stability relationships increase over time, due to a variety of forms of ecological complementarity. We propose to utilize a combination of approaches, with experiments in the field, iDiv Ecotron, and microcosms, based on biodiversity-stability theory. In the Main Experiment, we have ~two decades of high-resolution, field-level (air temperature, air moisture, radiation), and plot-specific data (soil temperature and moisture) that will allow us to identify extreme climate events. Synthesizing data from the subplots of the ΔBEF Experiment allow us to study the role of soil history in long-term plant diversity effects on ecosystem functioning and stability. The unique database from multiple long-term experiments, combined with repeated measurements of a multitude of different ecosystem functions, allows us to study how biodiversity can buffer ecosystems as affected by climate extremes. We can also use these long-term plots and their assembled communities and excavate soil to expose them to certain environmental conditions like climate extremes in a controlled way in the iDiv Ecotron. Moreover, we can use soil (respectively selected microbial inocula which are used to form a synthetic microbial community) taken from the long-term Main Experiment to perform small-scale microcosm experiments, to test additional stressors or mechanisms under controlled laboratory or greenhouse conditions. All subprojects will closely collaborate in the field (Main Experiment) as well as in the iDiv Ecotron Experiment (ResCUE Experiment) or central microcosm experiment (DrY Experiment), while smaller teams of subprojects will work together in Complementary Microcosm Experiments (CoMic Experiments). Extensive synthesis work will integrate data and information across subprojects and research platforms.