Fig 4. The history of the introduction of Psidium guajava in the Galapagos islands.

The best models for the introduction history of P. guajava were estimated through Approximate Bayesian Computing (ABC) and suggest either a model of independent introductions into Isabela and later Santa Cruz from San Cristobal (A), or an initial introduction into Isabela from San Cristobal followed by introduction events from both islands into Sant Cruz (B). The map (C) shows a first introduction into San Cristobal (cyan) from an unknown source (presumably continental South America), which seeded a consecutive introduction into Isabela (t2). The population of Santa Cruz might have been formed by a single introduction from Isabela (t1(A)) or introductions from both San Cristobal and Isabela (t1(B)). It could be proposed that an independent introduction into Isabela also occurred (t2(h)) either before or after the population of San Cristobal.