Table 1.

Recapitulation table of the variables used in these study to test the direct and indirect species richness predictors.

species richness predictors	variables used in the analyses and description
direct factors
dispersal	dispersal rate: dispersal rate from any bioregion to the focal bioregion
evolutionary rate	speciation (or diversification) rate: average rate of the cladesa of the focal bioregion
evolutionary time	maximum clade age: age of the oldest cladea of the focal bioregion
indirect factors
climatic stability	area through time: integration of the focal bioregion area over the past 55 Myr
productivity	productivity: total productivity of the focal bioregion
temperature	temperature: mean temperature of the focal bioregion

^aWe only considered the clades in which all component species are found in the focal bioregion. See also the electronic supplementary material, figure S2.