Assessment of the alien plant management in natural areas of Spain.
The introduction of alien species triggers not only ecological consequences but also economic and human welfare impacts. In this paper we have analysed the impacts and management of naturalized exotic plants (invasive and non-invasive) in Spain, through surveys among public administrations. In total, 109 exotic plant species are being managed in 14 Autonomous Communities. Most of these species are present in protected areas competing with native species, some of them endemic. The taxa managed in more Autonomous Communities are Carpobrotus spp., Eucalyptus spp., Acacia spp., Cortaderia selloana and Ailanthus altissima. The total economic costs of plant invasions in Spain accounts for 50,487,637 Euro and is mostly spent for reducing populations of these species through mechanical methods. The species for which more money has been invested has been Eucalyptus spp., followed by Eichhornia crassipes and Pennisetum setaceum. The Autonomous Community where a highest inversion has been done to manage exotic plants is Andalusia, and in second term Extremaduro and Canary Islands. Nonetheless, the exact monetary costs of most of the applied management actions are unknown to the respondents therefore an accurate economic valuation is quite difficult at the moment.