Theory 75/Ecosystem/Invasions
Invasion Speed Is Growth Against Dispersal
The claim
The spread rate of an invader is set by the ratio of population growth rate to dispersal distance, so a fast-growing invader with short dispersal can outrun a slow one with long dispersal.
01Mechanism
Spread combines reproduction and movement; whichever limits produces the slower front.
02Prediction
Spread should track the ratio.
03Refutation
Spread tracking dispersal alone would remove growth.