RESUMO
Biological invasions are a major threat that affects negatively to biodiversity. Several hypotheses have been generated to explain why some species can naturalize in invaded areas. The hypothesis of biotic resistance is one of the best known, wich describe the ability of native communities to repel invaders; however it has been poorly studied in urban environments. Urban habitats are currently the most common ecosystem on the planet but have been poor studied. In this study, we do not found effect of communities on exotic species, but a negative and significant effect of climate was found. In conclusion, we can point out that is the abiotic resistance that is conditioning the naturalization of exotic species in urban environments, while the role of the biotic competition to repel the invasion is not important, rejecting the hypothesis of biotic resistance.