Plant community composition, and community wide foliar N content
We related changes in carbon fluxes to foliar traits and plant community composition. Specifically, we examined how abundances of plant functional groups (C3 and C4 grasses, leguminous and non-leguminous forbs), and plant nitrogen (N) content (weighted average for the whole community) influenced mass specific GPP and Re. Species cover data were visually estimated in a 1m × 1m area within each subplot. Cover data were aggregated by plant functional type. Community weighted foliar N data was measured by homogenizing aboveground plant biomass and analyzing subsamples of homogenized biomass. For this, vegetation was clipped in 2 clip strips, 10cm wide × 6 m long. Samples were air dried at 40 degrees C, ground and homogenized, and subsequently analyzed using a C-N analyzer (NA1500, Carlo-Erba Instruments or ECS 4010, COSTECH Analytical Technologies Inc.).