The IUCN recommends the use of two distinct schemes to assess the impacts of biological invasions on biodiversity at the species level. The IUCN Red List of Threatened Species (Red List) categorises native species based on their risk of extinction. Such assessments evaluate the extent to which different pressures, including alien species, threaten native species. The much newer IUCN Environmental Impact Classification for Alien Taxa (EICAT) categorises alien species on the degree to which they have impacted native species. Conceptually, the schemes are related. One would expect that: 1) if a native species is assessed as threatened under the Red List due to the impacts of alien species, then at least one alien species involved should be classified as harmful under EICAT; and 2) if an alien species is assessed as harmful under EICAT, then at least one native species impacted should be assessed as threatened by alien species under the Red List. Here we test this by comparing the impacts of alien gastropods, assessed using EICAT, to the impact on native species as assessed based on the Red List. We found a weak positive correlation, but it is clear there is not a simple one-to-one relationship. We hypothesise that the relationship between EICAT and the Red List statuses will follow one of three forms: i) the EICAT status of an alien species is closely correlated to the Red List status of the impacted native species; ii) the alien species is classed as ‘harmful’ under EICAT, but it does not threaten the native species with extinction as per the Red List (for example, the impacted native species is still widespread or abundant despite significant negative impacts from the alien species); or iii) the native species is classified as threatened under the Red List regardless of the impacts of the alien species (threatened species are impacted by other pressures with alien species potentially a passenger and not a driver of change). We conclude that the two schemes are complementary rather than equivalent, and provide some recommendations for how categorisations and data can be used in concert.

中文翻译：

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比较IUCN的EICAT和红色名录以改善对生物入侵影响的评估

IUCN建议使用两种不同的方案来评估物种一级生物入侵对生物多样性的影响。IUCN濒危物种红色名录（红色名录）根据自然物种灭绝的风险将其分类。此类评估评估了包括外来物种在内的各种压力对本地物种的威胁程度。IUCN较新的《 IUCN外来生物分类环境影响分类》（EICAT）将外来物种对本土物种的影响程度进行了分类。从概念上讲，这些方案是相关的。可以预期：1）如果由于外来物种的影响而将某本地物种评估为红色名录中的濒危物种，则至少应根据EICAT将涉及的一种外来物种归类为有害物种；2）如果根据EICAT将某外来物种评定为有害，然后应将至少一种受影响的本地物种评估为受红色名录中的外来物种威胁。在这里，我们通过比较使用EICAT评估的外来腹足动物的影响与根据红色名录评估的对本地物种的影响进行测试。我们发现了弱的正相关，但是很明显，没有简单的一对一关系。我们假设EICAT和红色名录状态之间的关系将遵循以下三种形式之一：i）外来物种的EICAT状态与受影响的本地物种的红色名录状态密切相关；ii）根据EICAT，外来物种被归类为“有害”，但按照《红色名录》的规定，外来物种没有灭绝的威胁（例如，尽管受到外来物种的重大负面影响，受影响的本土物种仍然广泛或丰富。或iii）不论外来物种的影响如何，该外来物种都被归类为“红色名录”中的受威胁物种（受威胁物种受到其他压力的影响，外来物种可能是乘客，而不是变化的驱动力）。我们得出的结论是，这两种方案是互补的，而不是等效的，并且就如何将分类和数据一起使用提供了一些建议。