Species Richness Gradients Vary Across Phylogenetic Scales
Aim: To determine how species richness gradients—commonly considered universal—vary across the phylogenetic hierarchy of birds and mammals, and to uncover how clade age and size predetermine the gradients. Location: Global. Time Period: Last 120 million years. Taxa Studied: Birds and mammals (~15,000 species). Methods: We used large-scale phylogenies of birds and mammals and captured the species r
