Abstract：
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.
摘要：
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外来入侵物种（IAS）。然而,由于持续存在的方法学挑战，在量化实际影响和评估特定物种对特定IAS的脆弱性的原因方面进行的研究很少。因此，驱动物种特定脆弱性的潜在种间机制仍然知之甚少，即使它们可以大大提高风险评估的准确性。鉴于IAS生态影响的种间相互作用通常是由物候同步形成的，我们检验了以下假设：本地物种与IAS之间的繁殖物候在时间上的错配可以减轻其生态影响。专注于侵入性的美国牛蛙（Lithobatescatesbeianus），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相结合，以及关于育种物候的公民科学综合数据。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其物候错配的影响。实地研究表明，增加牛蛙eDNA浓度对本地两栖动物物种丰富度和群落结构具有显着的负面影响。这些观察是由物种对入侵牛蛙的特定脆弱性形成的，春季后期和夏季繁殖的物种受到强烈影响，而冬季繁殖物种未受影响。全球荟萃分析证实了这一趋势。在物候不匹配与牛蛙的影响之间观察到显着的负相关。具体来说,在存在牛蛙的情况下，繁殖物候与入侵牛蛙相差6周或更短的本地两栖动物物种比物候与牛蛙相差6周以上的物种更可能不存在。一起来看,我们提出了一种基于水性eDNA定量条形码和metabarcoding相结合的新方法，以量化生物入侵者在社区一级的生态影响。我们表明，无论生态学或方法学背景如何，本地物种和入侵物种之间的物候错配都可以很好地预测入侵影响。因此,我们主张将原生物候和IAS物候之间的时间一致性整合到入侵影响框架中。
