FIGURE 2. Scale effects on patterns of altitudinal species richness and testing of four generalized diversity models.

A, Schematic illustration of expected species richness patterns for four diversity models (see the text, Methods and Supplementary Fig. 1 for additional details on models). B, Degree of correlation (Pearson) between expected and empirical species richness values in 100-m altitudinal zones when sampling the same data with different combinations of grain size (1, 9, 26, 48 and 81 km²) and scale of extent (omitting segments of 0, 500, 1,000, 1,500 and 2,000 m from the lower limit of the gradient as illustrated by the grey-shaded area of the small triangles next to each of the y axes). a, Models 1 and 2; b, model 3; c, model 4. C, As in B, but omitting segments from the upper limit of the gradient. D, Coloured squares indicate the model with the highest Pearson correlation (that is, the best fit) for 25 combinations of grain size and spatial extent when omitting segments from the lower (B) and upper (C) limits of the gradient, respectively, from the analysis.