Fire and Invasive Plant Species in the Mediterranean Basin

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, silvicultural, ornamental, or medicinal purposes, while many have been accidental introductions. Some plant invaders can significantly alter fire regimes by changing plant fuel properties. Research on biological invasions and fire 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 fires. On the contrary, dry, fire-prone habitats of the Mediterranean 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 fire. Ampelodesmos mauritanica is considered as non-native to Catalonia and it has been reported to expand in areas with high fire 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
• flammability
• fire
• natural ecosystems
• Mediterranean Basin