Anthropogenic fires favoured alien and native annuals. Thus, fire did not increase the alien/native ratio but increased the richness of alien species. The successful establishment of alien annuals was attributable to their ability to maintain rich seedbanks in burned areas and to the greater propagule arrival compared to native species. The native seedbank also survived fire, indicating that the herbaceous community has become highly resilient after centuries of human disturbances. Our results demonstrate that fire is a relevant factor for the maintenance of alien-dominated grasslands in the matorral and highlight the importance of considering the interactive effect of seed rain and seedbank survival to understand plant invasion patterns in fire-prone ecosystems.