Interactive effects of source and recipient habitats on plant invasions: distribution of exotic species in Chile

Aim: Most studies on invasibility consider the characteristics of the habitats colonized. However, the success of the establishment of exotic species can be conditioned by the characteristics of the donor communities. In this study, we analyse the extent to which the distribution of exotic herbaceous species in Chile is conditioned either by the climatic characteristics of the recipient area or by the environmental features of the source areas on the Iberian Peninsula. Location: Chile and the Iberian Peninsula (Portugal and Spain). Methods: for Chile, we characterized the exotic species according to their current Chilean distribution and their region of origin. For the Iberian Peninsula, we compiled the floristic composition of 11,702 releves. We classified each releve according to key habitat characteristics (bioclimate, soil nutrient status and type of community associated with human activities) and calculated the percentage of species in common with Chile in different climatic regions therein. Results: Over half of Chile’s exotic species exhibited a geographic distribution related to the climate of the recipient area. The main donor communities were those associated with ruderal and arable land habitats, although their importance depended upon the climate in the recipient area. Correspondence was observed between the climatic characteristics of the communities in the source area and those of the recipient areas. Main conclusions: the results highlight the influence of the characteristics of habitats in the source area on the successful establishment of exotic species in Chile. The relationships between source and recipient area are scale dependent, climate constituting the main driver at broad scale. Within each climatic region, the communities associated with habitats presenting greater anthropic influence act as the main donors. Both features indicate the existence of filters that select species pre-adapted to the climatic and habitat conditions in the recipient area