Theory 38/Geometry & Scale/Biogeography
Islands Scale With Area
The claim
Species richness on islands follows a power of area whose exponent is set by the ratio of immigration to extinction rates, not by area alone.
01Mechanism
Richness is an equilibrium between arrivals and losses; the exponent encodes how those rates scale with area, which varies with isolation.
02Prediction
The exponent should vary with isolation.
03Refutation
A universal exponent would remove the rate ratio.