Current knowledge of the Neozoa, Nutria and Muskrat in Europe and their environmental impacts

In this study we focus on literature dealing with differences in habitat use, environmental impact, reproductive output and management strategies concerning the nutria and muskrat in Germany and Europe. What is the current knowledge about these invasive species in European countries, and what management strategies exist so far? We summarised more than 200 references on these topics using common scientific databases. In their original distribution area, habitats suitable for muskrats are characterised by low water level fluctuations and high low water resources, wider river banks and higher water depths. In newly inhabited areas, different habitat structures are exploited, although an aquatic environment is required. In Europe, the presence of muskrats can lead to habitat changes and consequently to biodiversity loss. Overall, muskrats are regarded as generally being able to cope well with changing habitat conditions. Feeding on crops merely seems to be a behaviour restricted to new settlements in both nutrias and muskrats. Nutrias, too, often achieve a reduction in plant diversity through their choice of food in the newly populated areas. Additionally, an urban occurrence along with sightings of the animals during the day are almost exclusively observed in these areas. Concerning the modelling of nutria population development, low winter temperatures and aquatic habitats are substantial factors.Research on reproductive outcome of both species in Europe is rare, and mostly reaches back to before the millennium. However, both species do have high litter sizes and might reproduce all year round, which is not yet confirmed for all habitats. The environmental impact of the invasive alien species (IAS) ranges from a mere nuisance in private gardens up to severe damage on protective dykes and a reduction in biodiversity in several countries The management of the IAS is cost intensive and differs widely between countries.