EGU25-16403, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-16403
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Belowground niche partitioning and water uptake dynamics in temperate grasslands using stable isotopes
Sepideh Golshani1, Tomáš Hájek2, Undine Schöllkopf3, Johanna Harisson3, Hassan Jafari4, Barbora Rybová5, Katja Tielbörger1, and Maria Májeková1
Sepideh Golshani et al.
  • 1Eberhard Karls Universität Tübingen, Vegetation Ecology, Tübingen, Germany
  • 2Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
  • 3Landscape Ecology, University of Hohenheim, Stuttgart, Germany
  • 4Department of Biostatistics and Health Informatics, King's College London, United Kingdom
  • 5Centre for Energy Efficient Buildings, Czech Technical University in Prague, Bustehrad, Czech Republic

Belowground niche partitioning is a key mechanism for maintaining plant species diversity in grasslands. However, limited empirical data and precise methodologies restrict our understanding of plant belowground coexistence strategies. Here, we examined various scenarios of plant species niche overlap based on their water uptake depths. The study was conducted across 75 grassland plots within the Biodiversity Exploratories in three distinct German regions, using the natural abundance of oxygen stable isotopes (δ18O) to link the plant xylem water to its source depth in the soil (up to 50 cm). By applying plot-level and regional-level mixed model statistical methods, we first tested the accuracy of water uptake depth predictions of 25 species as one of the critical steps. These water uptake depth predictions were then used to calculate the overlap in resource uptake niches among single-species water uptake flexibility across regions, as well as different growth forms and root systems of species.

Our results demonstrate that water uptake depths strongly correlate with environmental factors such as soil type and the geographical gradient of the plots. Regional-level mixed models demonstrated higher accuracy, revealing similar variations in water uptake depths across regions and species compared to the plot-level approach, highlighting diverse water use strategies in grasslands. Furthermore, our niche overlap findings indicate that fibrous root systems generally show greater overlap than taproot systems. Additionally, the overlap calculations for single species across three regions showed diverse patterns, emphasizing the utility of stable isotopes in addressing various ecological questions. These findings enhance our understanding of belowground coexistence mechanisms and ecosystem dynamics, emphasizing the importance of precise measurement techniques in revealing the complex interactions that drive resource use in temperate grasslands.

How to cite: Golshani, S., Hájek, T., Schöllkopf, U., Harisson, J., Jafari, H., Rybová, B., Tielbörger, K., and Májeková, M.: Belowground niche partitioning and water uptake dynamics in temperate grasslands using stable isotopes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16403, https://doi.org/10.5194/egusphere-egu25-16403, 2025.