In 2006, for the first time in more than 300 years, a beaver settlement in Vorarlberg was detected. The immigrants from Switzerland are a proof for the successful reintroduction of an almost extinguished species in Europe by man. The primary goal of this study is to assess the quality of habitats for the beaver along the Old Rhine, based on the evaluation method after KEMNADE et al. (2002). Furthermore, by using a beaver track mapping, it should be clarified what habitats are already populated by beavers and which role habitat qualities play in the colonization of beavers. Based on this information, the evaluation method is subject to a critical analysis. To provide the basis for future beaver management, finally, potential conflicts between humans and beavers are documented. The evaluated data show clear differences in habitat quality for the 6 study areas along the Old Rhine. The natural area "Eselschwanz" exhibits a particularly good habitat quality, based on the availability of woodland vegetation. A good quality habitat is found in the areas of "Gaißau" and "Bisewäldli". The other three areas, "Mündung", "Untere Fließstrecke Höchst" and "Obere Fließstrecke Höchst”, show an insufficient habitat quality. At the "Eselschwanz", as the most attractive area for beavers along the Old Rhine, the most beaver-tracks were found. In the further course of spread, the area "Obere Fließstrecke Höchst” was colonized, which is, according to the classification of Kemnade et al. (2002), a habitat with inadequate quality. This suggests that either important habitat factors were ignored in the evaluation, or, in addition to the habitat quality, other factors for the colonization of an area are crucial. The validation of the method, according to KEMNADE et al. (2002), shows that the environmental claims of beavers, with regards to the availability of woodland vegetation and the natural condition of the riverbanks, are well recorded. The mapping of the surrounding area shows that there is potential for conflicts between beavers and human beings. Since a further expansion of beavers in eastern Switzerland and Vorarlberg is expected, concepts and management plans should be developed, which govern the handling of potential conflicts, and enable a long-term and sustained coexistence between human beings and animals.