Nothing influences species diversities more than the amount of area available to life.
Area works at several scales and is controlled by several processes.
At the dominant scale, the entire biogeographical province, diversity is set by the dynamics of speciation and extinction. Other scales echo this one. The large areas of tropical provinces are a major reason the tropics have so many species. Unlike other scales, provincial area shows a linear relationship to species diversity. Preventing this mass extinction will require a sea change in our conservation strategies.