Dr. Karl Andraczek

My research focuses on understanding biodiversity’s role in ecosystem functioning, particularly how their feedbacks respond to global changes. I explore how these relationships scale across space and time, including both aboveground and belowground dimensions. Using advanced quantitative tools, experiments, and observations, I aim to clarify the causal relationships and underlying mechanisms, while also exploring their potential for nature-based solutions.

In my current post doc project at sDiv, I am investigating biodiversity's role in ecosystem functioning, especially if belowground plant functional diversity can enhance our understanding of ecosystem functioning, including its stability in response to climate change.

• January 2024 - present: PostDoc at sDiv
• May 2020 - May 2024: PhD Biology; Supervisor: Assistant Professor Fons van der Plas (Wagening University, Netherlands) and Professor Alexandra Weigelt (University of Leipzig, Germany), Title: Reciprocal relationships between plant diversity and ecosystem productivity
• October 2017 - September 2019: MSc Biology, Title: Will “Insect Armageddon” affect ecosystem nutrient cycling?
• October 2014 - September 2017: BSc Biology, Title: The effect of tree height on the density and composition of Nematode communities living in the tree crowns of oak and ash trees in the Leipzig floodplain forest

Andraczek, K., Dee, L.E., Weigelt, A., Hinderling, J., Prati, D., Le Provost, G., Manning, P., Wirth, C., van der Plas, F. et al. (2024): Causal inference methods reveal weak reciprocal relationships between productivity and plant biodiversity in managed grasslands. Journal of Ecology. This study proposes a novel framework to unravel the feedback effects between plant diversity and productivity in natural systems. Our work offers key insights into one of the longest-running debates in ecology regarding the relationship between biodiversity and productivity in natural systems and provides an important next step for investigating these feedback effects.

Andraczek, K., Weigelt, A., Cantuarias, C., et. al. (2023): Relationships between species richness and biomass production are context dependent in grasslands differing in land-use and seed addition. Scientific Reports 13, 19663. doi.org/10.1038/s41598-023-47020-z. This study provides key insights into the underlying drivers of plant diversity effects on productivity in managed grasslands, potentially explaining the largely inconsistent findings of previous studies. Our findings emphasize the importance of land-use intensity in modifying these relationships. Additionally, our study has implications for conservation, as we demonstrate that seed addition can be used to restore biodiversity without significant losses in productivity.

Andraczek, K., Weigelt, A., Hinderling, J., et al. (2023): Biomass removal promotes plant diversity after short-term de-intensification of managed grasslands. PLoS ONE 18(6): e0287039. doi.org/10.1371/journal.pone.0287039. Our study offers unique insights into how different drivers of grassland management modify the indirect effects of productivity on plant diversity. We demonstrate that biomass removal (through mowing and grazing) promotes diversity by reducing the negative effects of productivity, primarily by alleviating light competition. However, we found that these indirect effects depend on environmental conditions, highlighting the importance of climatic factors in shaping diversity-productivity relationships.

Alexandra, W.*, Mommer, L.*; Andraczek, K. et al. (2023): The importance of trait selection in ecology. Nature 618, E29–E30. doi.org/10.1038/s41586-023-06148-8. (*shared first author). In this commentary, we reflect on the causes of the apparent discrepancy between two recently published global trait analyses (Carmona et al. 2021 and Weigelt et al. 2021). We emphasize the importance of trait selection, which can strongly influence the observed relationships, advocating for more careful ecological consideration based on knowledge of trait functionality.

Alexandra, W.*, Mommer, L.*; Andraczek, K. et al. (2021): An integrated framework of plant form and function: the belowground perspective. In: The New Phytologist 232 (1), S. 42–59. DOI: 10.1111/nph.17590. nph.onlinelibrary.wiley.com/doi/10.1111/nph.17590. (*shared first author). In this review, we propose a global framework for plant form and function from a whole-plant perspective by integrating root traits. We argue that above- and belowground traits are coordinated, while plant height and rooting depth form separate plant strategies—a hypothesis confirmed by our tests using global plant trait data. This highlights the multidimensional nature of plant trait variation, which better captures plant functioning across different environments.