Wetlands and fresh-water ecosystems, which also have environmental and socio-economic functions, provide a habitat for terrestrial and aquatic species from all the surrounds. Floodplain forests are of irreplaceable importance. They have to provide timber and other products, but they also play an essential environmental function in protecting biodiversity, enhancing the landscape and regulating climate, water and soil, and in addition they are also important for recreation. Floodplain forests also serve as a corridor for the diffusion of species and they are a temporal biotope and nature resource for species of adjacent ecosystems. But, sadly, floodplain forests are increasingly under threat and only small fragments remain, thus imposing the risk that many species could disappear. There is also a large number of invasive and expansive species which changes original floristic composition. Environmental disturbances or river regulations and deforestation of river flats have together endangered biotope types throughout Europe.