Null models of geographic range size evolution reaffirm its heritability

Most models of allopatric speciation predict that the two daughter species will have range sizes different from each other's and potentially from that of their common ancestor. However, I find that this difference is less than that expected under a variety of null models of range evolution. Sister species' range values may therefore become more similar in the time following speciation. Greater-than-expected similarity (symmetry) has also been treated as a form of range size heritability. I therefore compare the results of this symmetry approach to a test for phylogenetic signal, using the range sizes of North American birds. I find that range size is heritable under both tests. I suggest that null models for range size heritability should be informed by an explicit model of evolution. Comparative methods may give erroneous results if they fail to take the unusual form of inheritance of range size into account.