analyzed in relation to both climatic and
environmental variables and distance to urban centres. We also compared life-forms of alien and native
species. Precipitation and distance to an urban centre were important determinants of alien species
community richness and composition, and shrubland sites had significantly more alien species than
forest or steppe sites. Alien flora (15% of the species) was composed of a higher proportion of annuals and
biennials than native flora. Our results suggest that precipitation, distance to source population, and
anthropogenic disturbance influence the invasion process in this region, together with the availability of
open niches. This work stresses the importance of monitoring invasive species in natural reserves, and of
considering habitat types as well as idiosyncratic characteristics of the non-natives for developing
management strategies.