The S’Albufera Natural Park in Majorca protected nationally as a Natural Park; as an EU Special Protection Area for Birds (SPA); as a Wetland of International Importance under the Ramsar Convention and is the most extensive area of marshlands in the Balearics at the brackish interface between seawater and the freshwater inflow from the hinterland of Majorca. It is suggested that the whole marsh aquatic system is a saline freshwater gradient or ecocline containing a series of ecotones or sharp interfaces between differing aquatic and terrestrial habitats and these change with time resulting in a dynamic niches for plants and animals leading to the rich biodiversity of the site. The author reviews some of the existing literature relating to the site, particularly related to the aquatic flora of the brackish water ecocline to which new data are added and the significance of these changing habitat interfaces i.e. ecotones to the present ecology and conservation of the Park
