Why larger nations have disproportionate threat rates: area increases endemism and human population size

Global Red List data on mammals, birds and plants for over 100non-island nations are used to identify the impact of area, endemism, humanpopulation, and many other social variables (urbanized population,human-dominated land, national wealth, % land protected) on proportions ofthreatened species among nations. Human population size and, especially,proportion of endemic species emerge as the strongest correlates of proportionof threatened species in nations. Area tends to increase both human populationand proportion of endemics and thus increases the proportion of threatenedspecies. Increasing wealth is associated with increased relative threat inmammals and plants. Proportion of land protected is significantly associatedwith decreased relative threat in mammals and birds.