Data from: A theory of island biogeography for exotic species

The theory of island biogeography has played a pivotal role in the way ecologists view communities. However, it does not account for exotic species explicitly, which limits its use as a conservation tool. Here, I present the results of a long-term study of plant communities inhabiting an archipelago of small islands off the coast of New Zealand and derive a modified version of the theory of island biogeography to predict differences in the turnover and diversity of native and exotic species. Empirical results showed that, although species richness of both native and exotic plant species increased with island area, native species consistently outnumbered exotic species. Species turnover increased with species richness in both groups. However, opposite to species-area patterns, turnover increased more rapidly with species richness in exotic species. Empirical results were consistent with the modified version of the theory of island biogeography, which distinguishes exotic species from native species by decoupling extinction rates of exotic species from island area, because they are represented by only small populations at the initial stages of invasion. Overall results illustrate how the theory of island biogeography can be modified to reflect the dynamics of exotic species as they invade archipelagos, expanding its use as a conservation tool.

岛屿生物地理学理论（theory of island biogeography）在生态学家对生物群落的认知范式中发挥了核心作用。然而，该理论并未明确纳入外来物种（exotic species）的考量范畴，这限制了其作为生态保育工具的应用场景。本研究呈现了新西兰近海小型群岛上植物群落的长期调研结果，并推导得到岛屿生物地理学理论的修正版本，用于预测本土与外来物种的周转速率与多样性差异。实证结果显示，尽管本土与外来植物的物种丰富度均随岛屿面积增大而提升，但本土物种的数量始终多于外来物种。两类物种的周转速率均随物种丰富度升高而加快。然而与物种-面积关系的规律相悖的是，外来物种的周转速率随物种丰富度提升的增幅更为显著。实证结果与修正后的岛屿生物地理学理论相符：该修正理论通过将外来物种的灭绝速率与岛屿面积解耦，从而区分本土与外来物种——这是由于外来物种在入侵初期仅拥有小规模种群。整体研究结果阐明了如何对岛屿生物地理学理论进行修正，以反映外来物种入侵群岛的动态过程，拓展了其作为生态保育工具的应用范围。