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This paper presents three extreme examples of the potential consequences of human settlement on oceanic and continental islands. The Neotropical Pantepui continental archipelago of sky islands is an example of pristinity, which is due to the almost inexistent human impact because of the remoteness and inaccessibility of these islands as well as the lack of natural resources to exploit. Easter Island is used to illustrate almost total landscape degradation by deforestation and the exhaustion of natural resources, which has transformed the island into badlands with no signs of recovery. The Azores Islands have been chosen to illustrate landscaping as, after initial postsettlement deforestation and extractive practices, a further transformative phase occurred consisting of creating an almost totally anthropogenic landscape with mostly exotic species. The paper describes in some detail the developments of each case and the historical context in which they took place using historical, archeological and paleoecological evidence. Many intermediate states are possible among these three extremes, which can be represented with a ternary diagram (the PDL diagram), which is useful for characterizing the state of each island or archipelago, in terms of human impact, and to inform conservation and restoration practices.
The manuscript has been reviewed by three colleagues and modified accordingly.