Generalized linear models (GLM) were used to assess the effect of grazing treatment on the two biodiversity metrics, richness and unicity, and on forb:graminoid ratio and litter amount, while considering block, topographic position and treatment. Block was nested in topographic position, which was either hill or marine foreland. GLM with Poisson errors and log link function was used for species richness and for litter (standing dead intercepts), whereas ordinary Gaussian regression was used for the forb:graminoid ratio.
For litter and for forb:graminoid ratio, the procedure was run for raw intercept counts and for calibrated biomass in parallel.
Results
Biomass calibration model