Habitat affiliation of non-native plant species across their introduced ranges on Caribbean islands

Investigating the ability of non-native species to establish and invade different habitats is one of the most important approaches in the analysis of biological invasion mechanisms. In this study, we used a regional dataset of non-native plant species compiled for Caribbean islands to estimate the level of invasion of major habitat types in this region. Our results show that although non-native species are successfully invading all habitat types evaluated, they are exhibiting considerably higher affinity toward human-made habitats. Across these islands, highly anthropogenically altered habitats such as ruderal sites, pastures, and cultivated lands are the habitats showing higher levels of invasion compared to natural habitats with low levels of disturbance. We found a significant association between geographical origin and habitat invaded, with species originating from Asia, South America, and Africa overrepresented as invaders in the Caribbean. Additionally, a significant association between life-form and habitat invaded was detected, with more trees and herbaceous species than expected successfully invading ruderal habitats, and more trees and vines than expected invading natural forests. In general, non-native species invading habitats across Caribbean islands seem to be adapted to a broad range of successional stages ranging from highly disturbed human-made habitats to least disturbed natural forests. Our results highlight how complex interactions among human activity, geographical origin, plant life-form, and habitat affinity can determine patterns of invasions across broad landscapes.