ALBERT

Description: This dataset contains stomatal conductance, leaf greenness, and height of species in the Jena-Ecotron Experiment in 2012. This experiment was conducted in the Montpellier European Ecotron (CNRS, France), an advanced controlled environment facility for ecosystem research, and aimed at understanding the impact of plant species richness (4 vs. 16 species) for ecosystem carbon and water fluxes. The soil monoliths used in this experiment contained plant communities originating from the long- term Jena Experiment (50°57.1' N, 11°37.5' E, 130 m above sea level; mean annual temperature 9.3°C, mean annual precipitation 587 mm) established in May 2002. Twelve plots were selected for the Jena-Ecotron study according to the following criteria: (1) the four functional groups grasses, legumes, small and tall herbs were present, (2) realized species numbers were close to sown species richness, and (3) plots were equally distributed across the experimental field site to account for different soil textures. Large monoliths (2 m² surface area, diameter of 1.6 m, 2 m depth with a weight of 7 to 8 tons) including intact soil and vegetation were excavated in December 2011 and placed in lysimeters. In March 2012, before the start of the vegetation growth, the lysimeters were transported and installed in the Macrocosms platform of the Montpellier European Ecotron. Stomatal conductance (gs, mmol/m²/s) was measured with a portable leaf porometer (SC-1 Leaf porometer, Decagon Devices, Pullman, USA). Measurements were done in the auto mode using the first 30 s of stomatal conductance data to predict the final stomatal conductance under true steady state conditions. Leaf greenness (SPAD; unitless), an estimate of chlorophyll concentrations, was obtained by measuring the absorption of two different wavelength (650 nm and 940 nm) with a portable chlorophyll meter (SPAD-502; Konica-Minolta, Osaka, Japan). The growth height of three shoots (Ind h; cm) per species and unit was measured with a ruler. Values of stomatal conductance, leaf greenness and growth height of the individual measurements were averaged per species per plot.

Description: This data set contains aboveground plant biomass (Sown plant species, Weed plant biomass, the biomass of dead plant material, and the biomass of unidentified plant material) per plots collected in 2012 from a grassland trait diversity experiment (the Jena Trait Based Experiment). The experiment consists of 20 plant species that were assigned to one of three species pools: 1. Species that vary along a gradient of spatial leaf and root trait similarity, 2. Species that vary along a gradient of phenological trait similarity and 3. Species that vary along a gradient of both spatial and phenological similarity (see Ebeling et al. 2014). The experiment consists of 138 grassland plots 3 x 3 m in size that was established within the Jena Experiment, Germany, in 2011. Plots vary in plant species richness (1, 2, 4, or 8 species) and functional diversity (1, 2, 3, 4 functional diversity levels, where 1 indicates species are most similar and 4 being most dissimilar in functional traits). Plots were maintained by manual weeding in March, July and September. Biomass was harvested twice in 2012 (during peak standing biomass in late May and in late August) on all experimental plots. Plots were mown to the same height directly following biomass harvest. Plant biomass was harvested by clipping the vegetation at 3 cm above ground in two 0.2 x 0.5 m quadrats per plot. The location of these rectangles was assigned prior to each harvest by random selection of coordinates within the core area of the plots (i.e. the central 10 x 15 m). The positions of the rectangles within plots were identical for all plots. The harvested biomass was sorted into categories: individual species of the sown plant species, 'Weed' plant species (species not sown in a plot), detached 'Dead' plant material, and remaining plant material that could not be assigned to any category ('Rest'). All biomass was dried to constant weight (70°C, 〉= 48 h) and weighed. The data from individual quadrats were averaged.