Range-diversity plots for conservation assessments: Using richness and rarity in priority setting

► Simultaneous use of species richness and range size identify conservation priorities. ► Mexican avifauna shows a positive relationship between species richness and rarity. ► Species richness and per-site range size follow different spatial structures. ► Richness of total and endemic bird species shows different spatial structures. ► Range-diversity plots readily identify richness-rarity sites and species inhabiting species-rich or species-poor regions.