Biological invasions are a major threat to global biodiversity with particularly strong implications for island biodiversity. Much research has been dedicated towards understanding historic and current changes in alien species distribution and impacts on islands and potential changes under future climate change. However, projections of how alien species richness and impacts on islands might develop in the future are still lacking. In the absence of reliable projections, expert-based assessments are a valuable tool to investigate the importance of different drivers and pathways and the distributions of potential impacts of future biological invasions. These insights can guide subsequent quantification efforts and inform invasive species management and policy. In this study, we performed a survey among 126 experts in invasion science ranging from scientists to managers and decision makers with a focus on island systems until the mid-21st century. The survey revealed that out of 15 drivers, six were considered important by almost all respondents (>90%). Of these, trade and transport was identified as most important at the introduction stage (99.2%) and land use/cover change as most important at the establishment (96.8%) and spread (95.2%) stage. Additionally, the experts considered that alien species were more likely to be introduced (93.7%) and spread (78.6%) as stowaways than through any other pathway. In general, respondents agreed that the impacts of alien species will increase on all types of islands, particularly on oceanic islands, followed by atolls and continental islands. Within islands, terrestrial ecosystems were assumed to be impacted more severely than marine ecosystems. Finally, the survey hints toward the potential for effective communication, scientific research and increased pro-active management of alien species on islands to reduce their future consequences. Given the major threat represented by invasive alien species on islands, these results provide crucial insights relevant for global and regional conservation efforts.

中文翻译：

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岛屿上的生物入侵未来会带来什么？基于专家的评估

生物入侵是对全球生物多样性的主要威胁，对岛屿生物多样性的影响尤为严重。许多研究致力于了解外来物种分布的历史和当前变化以及对岛屿的影响以及未来气候变化下的潜在变化。然而，关于外来物种丰富度和对岛屿的影响在未来可能如何发展的预测仍然缺乏。在缺乏可靠预测的情况下，基于专家的评估是研究不同驱动因素和途径的重要性以及未来生物入侵的潜在影响分布的宝贵工具。这些见解可以指导后续的量化工作，并为入侵物种管理和政策提供信息。在这项研究中，我们对 126 名入侵科学专家进行了一项调查，从科学家到管理人员和决策者，重点是直到 21 世纪中叶的岛屿系统。调查显示，在 15 位司机中，几乎所有受访者 (>90%) 都认为有 6 位很重要。其中，贸易和运输在引入阶段 (99.2%) 被确定为最重要，土地利用/覆盖变化在建立 (96.8%) 和传播 (95.2%) 阶段被确定为最重要。此外，专家们认为外来物种更有可能作为偷渡者被引入 (93.7%) 和传播 (78.6%)，而不是通过任何其他途径。总体而言，受访者同意外来物种对所有类型岛屿的影响都会增加，尤其是海洋岛屿，其次是环礁和大陆岛屿。岛屿内，陆地生态系统被认为比海洋生态系统受到的影响更严重。最后，该调查暗示了有效沟通、科学研究和加强对岛上外来物种的积极管理以减少其未来后果的潜力。鉴于岛屿上的外来入侵物种所代表的主要威胁，这些结果提供了与全球和区域保护工作相关的重要见解。