Invasion of exotic species in semi-arid Mediterranean rivers: What is new?
Aguiar, Francisca*,1, Ferreira, Maria Teresa1, Albuquerque, Antnio, 1 Instituto Superior de Agronomia, Lisboa, Portugal ABSTRACT- Riparian areas are known as being highly vulnerable to invasion by exotic species. Some studies suggested that semi-arid landscapes from riparian zones are more susceptible to invasion than the adjacent upland areas. Vegetation data was gathered from thirty 4 m2 subplots, sequentially disposed at three different valley locations: inundated and frequently flooded banks (FF), infrequently flooded valley floors (IF), and unflooded or rarely flooded higher floodplains (RF). Data was collected from six valleys of the river Guadiana, southern Iberia. A total of 287 vascular plant species were identified, but only 26 taxa (9.1%) were exotic, similarly to other Iberian Mediterranean-type rivers. A hierarchical classification showed that the species composition varied across the floodplain rather than along the river. Plant assemblages within location were rather hom
