The unregulated course of the Lafnitz River, especially downstream from the Stögersbach confluence, represents a unique biotope in Central Europe. With its approximately 40 meanders, this section is the most intricately structured part of the entire river course, offering a multitude of habitats for both flora and fauna. The undisturbed flow dynamics are enhanced by heavy summer rainfall, which frequently leads to flooding. These floods promote the pronounced erosion of the banks, a phenomenon known in ecology as cut and point banks.
An important aspect of this nature reserve is the breeding population of typical river bird species such as the little ringed plover (Charadrius dubius), the common sandpiper (Actitis hypoleucos), and the common kingfisher (Alcedo atthis), which depend on these specially shaped banks.
In addition, the extensive unregulated sections of the Lafnitz, together with the Raab River, provide habitat for the endangered European otter (Lutra lutra). This species, which in Austria is mainly found in the waters of the Mühlviertel and Waldviertel regions as well as on the lower reaches of the Raab, Lafnitz and Feistritz rivers, benefits from an intact and diverse aquatic landscape, which is essential for its reproduction and foraging.