FIGURE 1. Scale effects on altitudinal species richness patterns.

These bivariate plots, generated by repeated sampling of the same data set, show the empirical species richness patterns based on 25 combinations of scale of extent (y axis) and grain size (x axis). The surveyed gradient was reduced by omitting segments from the lower limit. The sampled gradients are illustrated by the grey shaded areas in the triangles adjacent to the y axes. (Supplementary Fig. 2 shows the effects of scale as a result of omitting segments from the upper limit of the gradient.)