Grassland Ecosystems Become More Resilient with Age

Reduced biodiversity affects the stability of the entire ecosystem. A long-term experiment now shows that grassland plant communities with multiple species need about 10 years to adjust to each other and produce an even amount of biomass again.

Jena Experiment
Durch Evolution nimmt in vielfältigen Pflanzengemeinschaften im Laufe der Zeit die Arbeitsteilung zwischen den verschiedenen Arten zu. (Image: Alexandra Weigelt)

Recent experiments have shown that the loss of species from a plant community can reduce ecosystem functions and services such as productivity, carbon storage and soil health. This reduced functioning may also destabilize the ecosystem in its ability to maintain ecosystem functions and services in the long term. However, assessing this is only possible if experiments can be maintained for a sufficient length of time.

Stable biomass production after 10 years

In a new study, researchers from the University of Zurich and colleagues from Leipzig and Jena analyzed the stability of plant biomass production over two decades in one of the longest-running grassland biodiversity experiments in the world, the Jena Experiment in Germany. After more than a decade, plant species in more diverse experimental communities complemented each other in producing stable biomass at the community level. At low plant diversity, by contrast, this “compensatory” effect was observed and community biomass varied much more from year to year. During the first decade of the experiment, species-rich communities had not yet stabilized because of large fluctuations in species populations. This long-term research shows that biodiversity plays an increasingly important role in stabilizing ecosystem productivity over time as plant communities mature.

Diverse species communities sustain ecosystems in the long term

“We now realize that the mechanisms by which diverse species communities maintain ecosystem functioning in the long term are continually developing even after two decades,” says first author Cameron Wagg of the University of Zurich. Such findings in this study highlight the importance of long-term research studies to fully appreciate the invaluable role of biodiversity for supporting ecosystem functions and services into the future.

Bernhard Schmid, professor at the Department of Geography adds: “These novel results fit with other recent findings of our research group, suggesting that over time evolutionary processes in diverse plant communities select the most ‘collaborative’ plant genotypes among the different species, thus increasing division of labor, community productivity and ecosystem stability.” Because ecosystem stability incurs resilience in the face of environmental perturbations, it follows that in a changing world, older, more diverse ecosystems should be valued particularly highly.

Literature:

Cameron Wagg et al. Biodiversity – stability relationships strengthen over time in a long-term grassland experiment. Nature Communications, 14. Dezember 2022. Doi: 10.1038/s41467-022-35189-2.