Levels of plant invasions in different habitat types were assessed in several regional studies, but few of them were from the Mediterranean. Here we compare the levels of vascular plant invasion across habitats and plant communities of Sicily. We used a large dataset of plant species presences/absences in vegetation plots to analyze the invasion patterns across habitats considering biogeography, life form and phenology of alien plants. Vegetation plots were classified based on the EUNIS classification of European habitats. The invasiveness of each species was expressed in terms of its absolute and percentage frequency. Representation of different life forms and phenological patterns was compared between alien and native species. The fidelity of alien species to individual habitats was calculated using the phi coefficient. Our analysis shows that annual and woody species are the most represented life forms in the alien flora of Sicily and that alien species tend to have a longer flowering period than the native species. The investigated habitats differed strongly in their level of invasion by alien species, ranging from 0 to 15.6% of aliens of all species recorded. Most of the habitats were colonized by very few alien species or completely lacked them, except for sandy coasts, naturally-disturbed riverbeds, and synanthropic habitats. It must be noted, however, that the number of alien species occurring in a given habitat does not relate to the severity of the impact of invasion in that habitat. Some habitats are invaded by few (or single) species, which attain a high cover, transforming the whole ecosystem. The habitat-based approach proved to be suitable for evaluating the habitat specificity and frequency of alien species at a regional scale, improving the capacity for risk assessment in different ecological contexts.

在一些区域研究中评估了不同栖息地类型中植物入侵的水平，但其中很少来自地中海。在这里，我们比较了西西里岛各个生境和植物群落中维管植物的入侵水平。考虑到生物地理学，生命形式和外来植物物候，我们使用了植被地块中植物物种存在/缺失的大型数据集来分析跨生境的入侵模式。根据EUNIS对欧洲生境的分类对植被区进行了分类。每个物种的入侵性以其绝对值和百分比频率表示。比较了外来物种和本地物种的不同生命形式和物候模式的表示。使用phi计算外来物种对单个生境的保真度系数。我们的分析表明，一年生和木本物种是西西里岛外来植物区系最具代表性的生命形式，外来物种的开花期往往比本地物种长。被调查的栖息地在被外来物种入侵的程度上差异很大，在记录的所有物种的外来物种中占0％至15.6％。除了沙质海岸，自然扰动的河床和合人类的生境之外，大多数生境都很少被外来物种殖民或完全缺乏外来物种。但是，必须指出的是，在给定栖息地中出现的外来物种的数量与该栖息地中入侵影响的严重程度无关。一些栖息地受到很少（或单个）物种的入侵，这些物种获得了很高的覆盖率，从而改变了整个生态系统。