Human-Driven Diversity Changes in Caribbean Parrots Across the Holocene

Abstract

Islands are windows for studying how humans have shaped biogeographic distributions. However, modern diversity patterns on islands are the outcome of evolutionary, ecological, and anthropocentric factors across long-temporal scales that often leave little evidence of the interactions among them. One exception are the parrots of the Caribbean which have a close commensal relationship with humans and an extensive fossil and archaeological record in the Holocene. Using modern and ancient DNA and radiocarbon dating, we present a temporal and spatial overview of the evolution, extirpation, and translocation of Amazona parrots across the Caribbean. Amazona colonized the Greater Antilles in the Pliocene and the most widespread parrot species, the Cuban Parrot, exhibits inter-island divergences throughout the Pleistocene. Within this radiation, we discovered a now extinct, genetically distinct lineage that survived on Turks & Caicos until human settlement of the islands. We also found that the narrowly distributed Hispaniolan Amazon had a range that once included the Bahamas and was introduced by indigenous people to Grand Turk and Montserrat. Our results show that datasets that transcend the extinct-living continuum highlight the long-term role of humans in altering the diversity and distribution of Caribbean biota.