The islands are isolated volcanic outcrops in the eastern Pacific Ocean, where the introduction of novel species quickly destabilises the archipelago's ecosystems.

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Dr Hickman hoped the findings would raise awareness of a novel impact of invasive species.

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For species, adaptations to novel environments and the need to avoid crossbreeding with those on the other side of the split are both plausible hypotheses.

ECONOMIST: Linguistic evolution: Received pronunciation | The