The “Lahn floodplain between Atzbach, Dutenhofen and Heuchelheim” is one of the largest nature reserves in central Hesse. The designation as a nature reserve ended decades of gravel mining, which had left clear traces in the area, and ensured the preservation of the more than 1 km wide grassland floodplain on both sides of the Lahn. Regularly flooded floodplain meadows, the riverside floodplain forest, shallow water and silting areas, steep walls, gravel banks, ponds and pools form an extremely structurally rich mosaic of valuable habitats for numerous, partly highly endangered animal and plant species. The area is of particular importance for migratory birds such as cranes, which stop here in their hundreds every year on their flight to their summer and winter quarters and recharge their batteries for their onward flight. The floodplain landscape is equally important for a few breeding pairs of rare meadow breeders. The habitat is also home to 280 plant species, 22 dragonfly species, numerous butterfly and grasshopper species, as well as various amphibian species, which makes it particularly worth protecting, including as a local recreation area.
The Lahnaue is designated as a European protected area.