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.).