The Melbtal valley is designated as a nature reserve by the Kottenforst landscape plan, which came into force on February 27, 2013. The area has a total size of around 20 hectares and is located between Ippendorf and Poppelsdorf. It includes the steep and in part deeply incised valley of the Engelsbach stream with the near-natural forest stream, swamp and seepage springs as well as the accompanying hillside forests.

The Melbtal valley is an important biotope for numerous rare and endangered animal and plant species, in particular birds, bats and amphibians.