ISRAEL JOURNAL OF ECOLOGY & EVOLUTION, Vol. 58, 2012, pp. 195–203 10.1560/IJEE.58.2-3.195 *Author to whom correspondence should be addressed. E-mail: marianou@biol.uoa.gr Received 19 October 2011; accepted in revised form 5 March 2012. FIRE AND INVASIVE PLANT SPECIES IN THE MEDITERRANEAN BASIN Margarita arianoutsou a, * and Montserrat Vilà b a Department of Ecology and Systematics, Faculty of Biology, School of Sciences, National and Kapodistrian University of Athens, 15784 Athens, Greece b Estación Biológica de Doñana (EBD-CSIC), Avda. Américo Vespucio, s/n Isla de la Cartuja, E-41092, Sevilla, Spain ABSTRACT Invasive species often have ecological and economic impacts. They can threaten biological diversity in various ways, from reducing genetic variation and eroding gene pools, through the extinction of endemic species, to altering habitat and ecosystem functioning. Biological invasions also have economic impact. Vascular plants are among the most ubiquitous invasive organisms. The majority of alien plants have been introduced for agricultural, silvicul- tural, ornamental, or medicinal purposes, while many have been accidental introductions. Some plant invaders can signiicantly alter ire regimes by changing plant fuel properties. Research on biological invasions and ire is rather limited in the Mediterranean Basin compared to othe mediterranean areas of the world; this is probably because plant invasions occur mainly in human-made and disturbed habitats or in wet areas, which are not regularly subjected to ires. On the contrary, dry, ire-prone habitats of the Mediterra- nean region seem not to be so susceptible to alien plant invasions. However, the expansion of perennial grasses over shrubs in areas frequently burned has been reported as a critical issue related to invasions. Two examples come from Spain. The local abundance of the exotic Cortaderia selloana has been related to ire. Ampelodesmos mauritanica is considered as non-native to Cat- alonia and it has been reported to expand in areas with high ire frequencies. Finally, in areas of Southern Europe with less dry climates, such as northern and central Portugal, woody invasive species such as Acacia and Eucalyptus seem to become a problem and an increased concern for forest managers in burned areas. Keywords: alien plants, lammability, ire, natural ecosystems, Mediterranean Basin INTRODUCTION Biological invasions have been a scientiic topic for some time (Elton, 1958). However, it has only been during the last two decades that the ecological consequences of these invasions have been researched extensively. This is due to the fact that some invasive