Data from: Global mammal betadiversity show parallel assemblage structure in similar but isolated environments

The taxonomic, phylogenetic and trait dimensions of betadiversity each
provide unique insight into the importance of historical isolation and
environmental conditions in shaping global diversity. These three
dimensions should, in general, be positively correlated. However, if
similar environmental conditions filter species with similar trait values,
then assemblages located in similar environmental conditions, but
separated by large dispersal barriers, may show high taxonomic, high
phylogenetic, but low trait betadiversity. Conversely, we expect lower
phylogenetic diversity but higher trait biodiversity among assemblages
that are connected but are in differing environmental conditions. We
calculated all pairwise comparisons of ~110x110 km grid-cells across the
globe for ~5,000 mammal species (~70 million comparisons). We considered
realms as units representing geographic distance and historical isolation
and biomes as units with similar environmental conditions. While
betadiversity dimensions were generally correlated, we highlight
geographic regions of decoupling among betadiversity dimensions. Our
analysis shows that assemblages from tropical forests in different realms
had low trait dissimilarity while phylogenetic betadiversity was
significantly higher than expected, suggesting potential convergent
evolution. Low trait betadiversity was surprisingly not found between
isolated deserts, despite harsh environmental conditions. Overall, our
results provide evidence for parallel assemblage structure of mammal
assemblages driven by environmental conditions at a global scale.