Floristic homogenization of South Pacific islands commenced with human arrival

Nichola A. Strandberg*, Manuel J. Steinbauer*, Anna Walentowitz, William D. Gosling, Patricia L. Fall, Matiu Prebble, Janelle Stevenson, Janet M. Wilmshurst, David A. Sear, Peter G. Langdon, Mary E. Edwards, Sandra Nogué*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The increasing similarity of plant species composition among distinct areas is leading to the homogenization of ecosystems globally. Human actions such as ecosystem modification, the introduction of non-native plant species and the extinction or extirpation of endemic and native plant species are considered the main drivers of this trend. However, little is known about when floristic homogenization began or about pre-human patterns of floristic similarity. Here we investigate vegetation trends during the past 5,000 years across the tropical, sub-tropical and warm temperate South Pacific using fossil pollen records from 15 sites on 13 islands within the biogeographical realm of Oceania. The site comparisons show that floristic homogenization has increased over the past 5,000 years. Pairwise Bray–Curtis similarity results also show that when two islands were settled by people in a given time interval, their floristic similarity is greater than when one or neither of the islands were settled. Importantly, higher elevation sites, which are less likely to have experienced human impacts, tended to show less floristic homogenization. While biotic homogenization is often referred to as a contemporary issue, we have identified a much earlier trend, likely driven by human colonization of the islands and subsequent impacts.

    Original languageEnglish
    Pages (from-to)511-518
    Number of pages8
    JournalNature Ecology and Evolution
    Volume8
    Issue number3
    DOIs
    Publication statusPublished - 15 Jan 2024

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