Total species richness (γ) explained by alpha and beta components of diversity at three spatial scales: the mean species number per plot (α₁), the mean species number per site (α₂), the mean species number per management category (α₃), the average addition of species from plots to sites (β₁), the average addition of species from sites to management categories (β₂), the average addition of species from management categories to the total species number (β₃) and the total species number (γ).

<p>The grey bars correspond to the observed values and the black bars to the expected values based on a null model. The asterisks indicate the levels of statistical significance (* corresponding to <i>p</i><0.001) for a difference between observed and expected values.