Caribbean Birds

Taxon Cycle Model

Diagram of the progression of species from stage 1 to stage 3, and back to stage 1, of the taxon cycle. Because no species in the Lesser Antilles with a fragmented distribution is taxonomically undifferentiated, we assume that the sequence from stage 1 to stage 3 involves differentiation (stage 2) followed by extinction of island populations. If movement between islands is frequent, taxa may remain in stage 1 without progressing through the cycle. Further extinction of island populations may convert stage 3 to stage 4 (single-island endemics) and eventually lead to global extinction if no re-expansion phase occurs.