Evoregions: mapping shifts in phylogenetic turnover across biogeographic regions

1. Biogeographic regionalization offers context to the geographical
evolution of clades. The positions of bioregions inform both the spatial
location of clusters in species distribution and where their most
important boundaries are. Nevertheless, defining bioregions based on
species distribution alone only incidentally recover regions that are
important during the evolution of the focal group. The extent to which
bioregions correspond to centers of independent diversification depends on
how clusters of species composition naturally reflect the radiation of
single clades, which is not the case when mixed colonization occurred. 2.
Here, we showed that using phylogenetic turnover based on fuzzy sets,
instead of species composition, led to adequate detection of
evolutionarily important bioregions, that is, regions that account for the
independent diversification of lineages. Mapping those evoregions in the
phylogenetic tree quickly reveals the timing and location of major shifts
of biogeographic regions. Moreover, evolutionary transition zones are
easily mapped, and permits the recognition of regions with high
phylogenetic overlap. 3. Our results using the global radiation of rats
and mice (Muroidea) recovered four evoregions—three major evolutionary
arenas corresponding to the Neotropics, a Nearctic-Siberian, and a
Paleotropical-Australian evoregion, and a fourth and fuzzy Afro-Palearctic
evoregion. Transition zones among evoregions were minimized when compared
to other methods considering or not phylogenetic information, that is, the
affiliation of cells to their assigned region was higher using evoregions
than other approaches. Such higher affiliation values result from the
lower phylogenetic overlap within evoregions, as expected when single
radiations are accounted for as best as possible. 4. Evoregions is a
useful framework whenever the question is related to the identification of
the most important centers of a group’s diversification history and its
evolutionary transitions zones.