The role of biodiversity for element cycling and trophic interactions: an experimental approach in a grassland community

The focus of a new experiment, set up in Jena in spring 2002, are the effects of biodiversity on element cycles and the interaction of plant diversity with herbivores and soil fauna. The experimental design explicitly addresses criticisms provoked by previous biodiversity experiments. In particular, the choice of functional groups, the statistical separation of sampling versus complementarity effects, and testing for the effects of particular functional groups differ from previous experiments. Based on a species pool of 60 plant species common to the Central European Arrhenatherion grasslands, mixtures of one to 16 (60) species and of one to four plant functional groups were established on 90 plots (20 in x 20 m) with nested experiments. In order to test specific hypotheses 390 additional small-area plots (3.5 m x 3.5 m) were set-up. Exact replicates of all species mixtures serve to assess the variability in ecosystem responses. In a dominance experiment, the effects of interactions among nine selected highly productive species are studied. Each species is grown as monoculture replicated once.