The invasion of Donana National Park (SW Spain) by the mosquito fern (Azolla filiculoides Lam)

The invasion of Do ñana National Park (SW Spain) by the mosquito fern (Azolla filiculoides Lam)In 2001, Azolla filiculoides Lam., a floating pteridophyte native to the New World, was found in Doñana National Park (SW Spain), an European protected area well known for its high value from a conservation point of view and for its ecological vulnerability.Until that time, there had been no exotic aquatic macrophyte observations in the National Park.Since then, surfaces covered by Azolla filiculoides have increased explosively forming thick floating mats which eliminate submersed plants, and seriously threaten the aquatic ecosystems in this important protected area.