Figure 2.

Illustration of how the BEF relationship changes with spatial scale in cases I–IV. Panel (a) shows how the BEF slope, b_A changes relative to the mean local slope , at different spatial scales (see electronic supplementary material, figure S1 for raw values of b_A). Panel (b) shows the R² of this relationship. The four cases are shown in the different panels—no variation in local species richness or local b_i (case I), variation in local a_i (case II), variation in local S (case III) or variation in local b_i (case IV). The solid line shows the median across 100 replicate simulations each consisting of 2000 replicate regions at each scale. Inter-run variability omitted for clarity in panel (a), but shown in electronic supplementary material, figure S1. In panel (b), the interquartile range is smaller than the width of the lines and so is not shown. (Online version in colour.)