Horizon scans have emerged as a valuable tool to anticipate the incoming invasive alien species (IAS) by judging species on their potential impacts. However, little research has been conducted on quantifying actual impacts and assessing causes of species‐specific vulnerabilities to particular IAS due to persistent methodological challenges. The underlying interspecific mechanisms driving species‐specific vulnerabilities therefore remain poorly understood, even though they can substantially improve the accuracy of risk assessments. Given that interspecific interactions underlying ecological impacts of IAS are often shaped by phenological synchrony, we tested the hypothesis that temporal mismatches in breeding phenology between native species and IAS can mitigate their ecological impacts. Focusing on the invasive American bullfrog (Lithobates catesbeianus), we combined an environmental DNA (eDNA) quantitative barcoding and metabarcoding survey in Belgium with a global meta‐analysis, and integrated citizen‐science data on breeding phenology. We examined whether the presence of native amphibian species was negatively related to the presence or abundance of invasive bullfrogs and whether this relationship was affected by their phenological mismatches. The field study revealed a significant negative effect of increasing bullfrog eDNA concentrations on native amphibian species richness and community structure. These observations were shaped by species‐specific vulnerabilities to invasive bullfrogs, with late spring‐ and summer‐breeding species being strongly affected, while winter‐breeding species remained unaffected. This trend was confirmed by the global meta‐analysis. A significant negative relationship was observed between phenological mismatch and the impact of bullfrogs. Specifically, native amphibian species with breeding phenology differing by 6 weeks or less from invasive bullfrogs were more likely to be absent in the presence of bullfrogs than species whose phenology differed by more than 6 weeks with that of bullfrogs. Taken together, we present a novel method based on the combination of aqueous eDNA quantitative barcoding and metabarcoding to quantify the ecological impacts of biological invaders at the community level. We show that phenological mismatches between native and invasive species can be a strong predictor of invasion impact regardless of ecological or methodological context. Therefore, we advocate for the integration of temporal alignment between native and IAS's phenologies into invasion impact frameworks.

中文翻译：

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物候不匹配减轻了生物入侵者对两栖动物群落的生态影响


地平线扫描已成为一种有价值的工具，可以通过判断物种的潜在影响来预测即将到来的外来入侵物种 (IAS)。然而，由于持续存在的方法学挑战，很少有研究量化实际影响并评估特定 IAS 的物种特异性脆弱性的原因。因此，驱动物种特异性脆弱性的潜在种间机制仍然知之甚少，尽管它们可以大大提高风险评估的准确性。鉴于 IAS 生态影响背后的种间相互作用通常是由物候同步性决定的，我们测试了以下假设：本地物种和 IAS 之间繁殖物候的时间不匹配可以减轻其生态影响。我们将比利时的环境 DNA (eDNA) 定量条形码和元条形码调查与全球荟萃分析结合起来，并整合了有关繁殖物候学的公民科学数据。我们研究了本地两栖动物物种的存在是否与入侵牛蛙的存在或丰度呈负相关，以及这种关系是否受到物候不匹配的影响。实地研究揭示了牛蛙 eDNA 浓度增加对本地两栖动物物种丰富度和群落结构产生显着的负面影响。这些观察结果是由物种特定的入侵牛蛙脆弱性决定的，春末和夏季繁殖的物种受到严重影响，而冬季繁殖的物种则不受影响。全球荟萃分析证实了这一趋势。在物候不匹配和牛蛙的影响之间观察到显着的负相关关系。 具体而言，与入侵牛蛙的繁殖物候期相差 6 周或更短的本地两栖动物物种，在牛蛙存在的情况下，比物候期与牛蛙的物候期相差超过 6 周的物种更有可能消失。总之，我们提出了一种基于水性 eDNA 定量条形码和元条形码相结合的新方法，以量化生物入侵者在群落水平上的生态影响。我们表明，无论生态或方法背景如何，本地物种和入侵物种之间的物候不匹配可以成为入侵影响的有力预测因素。因此，我们主张将本地物候和 IAS 物候之间的时间一致性整合到入侵影响框架中。