Community History and Ecosystem Functioning

Background

It is conceivable that specific interaction networks among species develop over time in natural plant communities, making them more productive and more stable than newly assembled communities. The aim of this project is to test if such effects of community history can be detected after 8 years in experimental grassland communities of the "Jena Experiment", a large biodiversity research platform in Germany.

Methods

In a fist subproject we test if selection for increased combining ability occurs if different species are growing together in mixed communities for a prolonged time. We compare this selection regime providing a common community history with the results of selection of the two species in separate monocultures. In addition, we expect that newly established mixed communities will have higher yield if they contain plants that have been selected in mixtures rather than monocultures. If the tests were positive, it would suggest that 8 years of differential survival and reproduction in mixtures vs. monocultures can select for genotypes with high vs. low interspecific combining abilities.

In a second subproject we re-assemble the same experimental communities as established 8 years ago on the original plots of the Jena Experiment with plants taken from the 8-year old communities of the same plot (common plant history) or from the supplier which provided the original seeds in 2001 and with unsterilized (common soil history) or sterilized soil taken from the same plots. Here the prediction is that biodiversity effects based on complementary resource use and interactions with soil organisms will be stronger in re-assembled communities with common history. These communities should also be more stable temporally (in terms of invasibility, species abundances) than those without common history.

Measurements will focus on plant individuals and communities (survival, growth, morphology, reproduction, biomass); soil abiotic and biotic variables will be assessed in collaboration with other groups. Data will be analyzed with general linear models and mixed-model analysis of variance. The proposed research should contribute to the basic questions of how tightly integrated plant communities are and whether integration increases during community development (evolution of combining ability, plant–soil community assembly processes). A better understanding of these questions is essential because they are related to the management of biodiversity and ecosystem functioning.

Participants

Prof. Dr. Bernhard Schmid (Project Leader)
Varuna Yadav (Ph.D.)
Debra Zuppinger-Dingley (Ph.D.)
Terhi Hahl (Ph.D.)
Sofia van Moorsel (Ph.D.)

Co-operation partners

Dr. Gerlinde de Deyn, The Netherlands Institute of Ecology, Heteren
Dr. Nico Eisenhauer, Göttingen University, Germany
PD Dr. Pascal Niklaus
Dr. Jana Petermann, University of British Columbia, Vancouver, Canada
Prof. Wim van der Putten, The Netherlands Institute of Ecology, Heteren
Prof. Stefan Scheu, Göttingen University, Germany

Publications

Petermann, J.S., Fergus, A.J., Turnbull, L.A., Schmid, B. (2008). Janzen-Connell effects are both widespread and strong enough to maintain functional diversity in grasslands. Ecology 89: 2399-2406.

Petermann, J.S., Fergus, A.J., Roscher, C., Turnbull, L.A., Weigelt, A., Schmid, B. (2010). Biology, chance or history? The predictable re-assembly of temperate grassland communities. Ecology 91: 408-421.

Lipowsky, A., Schmid, B., Roscher, C. (2011). Selection for monoculture and mixture genotypes in a biodiversity experiment. Basic and Applied Ecology 12: 360-371.