THE MACROECOLOGY OF CYPRINELLA - CORRELATES OF PHYLOGENY, BODY-SIZE, AND GEOGRAPHICAL RANGE

Macroecologists interpret correlates of body size and geographical range size in an ecological context, but these patterns may also reflect historical or phylogenetic forces. We examined the relationship between range size and body size for a monophyletic group of 27 North American minnow species. Body size and range size were positively correlated, but both variables were also correlated with latitude. After controlling for effects of latitude, body size and range size were no longer correlated. The basal dichotomy of the cladogram defined an eastern and western clade; they differed in their geological and climatic histories and macroecological patterns. Within the western clade, only Bergmann's rule was confirmed. Within the eastern clade, both longitude and latitude of geographical range were positively correlated with body size. A simple measure of phylogeny was correlated with range size: species branching near the cladogram root had larger geographical ranges than species branching distally. After statistically removing the effects of latitude, longitude, and phylogeny, there was a significant positive correlation between body size and range size. Macroecological patterns are sensitive to phylogeny and speciation history, and they may be most informative for clades that occupy areas with a common climatic history.