Figure 3.

Relationships of three indices of spatial turnover with species richness and latitude. Associations are shown for species richness (a–c), and latitude (d–f), for (a,d) square-root transformed β_w, (b,e) β_sim and (c,f) β_j. The range of values at each latitude and species richness, respectively, is shown in grey and the latitudinal or species richness medians are plotted as open circles. In order to show these relationships more clearly, the graph for β_w is truncated at 3 and that of β_sim at 0.3.The omitted values constitute 1.8% (β_w) and 0.7% (β_sim) of the dataset: all have low species richness (max=186, median=4) but cover a wide range of latitudes. Southern latitudes are indicated as negative, northern ones as positive.