The floodplains of the Danube remained untouched up until the end of the 19th century. However, since then, its ecosystem has profoundly been changed due to several human interventions. Over 80% of the original riparian zone has been lost to dykes, pollution and climate change. In order to conserve the surviving natural habitats, there has been an increasing number of national parks and protected areas established since the 1970s all along the Danube and its tributaries. Despite this, since 2007, the Danube has been the only river in Europe included in the top list of WWF as endangered freshwater.