Fig. 2

Square of the difference between the changing rates of unseen probabilities in the sampled area a and unsampled habitat h, for different threshold t values. We choose a cutoff point here as 10⁻¹⁰ (shown as the black horizontal dashed line), after which the square of the difference would approach zero and thus decrease very slowly. Different curves represent different sampling fractions (or local area size) of the entire BCI forest plot used to infer the area size of the species pool. The optimal threshold positions for different sampling sizes are highlighted with vertical arrows