Projects

Modelling diversity-functioning relationships in grasslands

Scientist(s): Tanja Reinhold(PhD), Christian Wirth (PI)
Funding: DFG, Forschergruppe Biodiversität "The Jena Experiment" TP15 and Agence Nationale de la Recherche, France (DISCOVER project)
Duration: 2006-2007

Background: The Jena Experiment is one of the largest diversity experiments world-wide. Mixtures of grassland species were established to form a gradient in species diversity and functioning diversity to explore relationship between diversity and a range of ecosystem functions such as net primary production, soil carbon accumulation, nitrogen mineralization etc.

Objectives: We use the process-based grassland model GEMINI to identify the main mechanisms shaping the observed diversity-functioning relationships in the Jena Experiment. The mechanisms considered are - complementarity: diverse mixtures consisting of species with different strategies of resource acquisition and different phenology, exploit the available resources better than less diverse mixtures and therefore exhibit higher rates of functioning. - selection effect: diverse mixtures have a higher probability of harbouring highly productive and competitive species - plasticity (plasticity of plants in their traits related to resource acquisition ensures that complementarity is possible with a limited number of species).

The model approach will allow us to assess the relative importance of these individual mechanisms and further to identify the key traits of grassland species promoting such mechanisms. It also enables us to quantify the amount of functional diversity required to obtain positive diversity-functioning relationships and to study how robust these relations are under variable climate and varying management regimes.

Partners: Jean-Francois Soussana (INRA, Clermont-Ferrand, France), Jens Schumacher (MPI BGC), Hans Dähring (MPI BGC)

Link: http://www.the-jena-experiment.de/