Theory 56/Population/Species ranges
Range Is Dispersal Against Habitat
The claim
Species range size is set by the ratio of dispersal ability to habitat availability, so a good disperser in fragmented habitat has a smaller range than a poor disperser in continuous habitat.
01Mechanism
Range expansion requires both movement and places to settle; the ratio determines how far a lineage can spread.
02Prediction
Range should track the ratio.
03Refutation
Range tracking dispersal alone would remove habitat.