Figure 4.

Altitudinal range of species (max. 1,370 m) against their frequency of occurrence (max. 82 lakes), considering only species present in at least four lakes, by groups. Circles are species, represented in gray when narrow‐ranging (numbers are those of Figure 2, species identity in Appendix S2). Narrow‐ranging species are defined by computing 95% confidence intervals (dashed curves) for altitudinal range against the frequency of occurrence (9,999 randomizations of altitude values for each frequency). Letters (a, b) define groups significantly different (p < .05, Fisher's exact test)