Oceanic Islands: Models of Diversity

Abstract

Oceanic islands are unusual in their isolation, which has allowed the formation of uniquely evolved biotas that exhibit community characteristics such as disharmony, high endemism, and sometimes relictualism. Characteristics of species may include reduced dispersal capabilities, evolutionary innovations, and size and reproductive changes. Ecological and evolutionary changes play a key role in successful island colonization, and often result in adaptive radiation. While such circumstances may have facilitated rapid speciation, they also result in high rates of extinction, greatly accelerated since the arrival of humans. Human-mediated impacts on islands cannot be held back; however, the islands present a relatively simple system in which it is possible to understand the dynamics of species formation and loss.