Assessment of invasive muskrat Ondatra zibethicus distribution and impacts on ecosystems in Lithuania

After acclimatization muskrats spread over almost all Lithuania and increased to about 40 000 individuals in the 1980s. But since then the number of muskrats has decreased to about 2000 individuals. We used BINPAS (Bioinvasion Impact/Biopollution Assessment System) for terrestrial ecosystems, which is usually using for water ecosystems, to assess the impact of Ondatra zibethicus on native species and communities, on habitats, on ecosystems and the biopollution level (BPL). The impact of muskrats varied between different regions of Lithuania. Widespread and high numbers of muskrats, and strong biopollution of ecosystem functioning were identified in four regions of Lithuania – Nevėžis and Nemunas Rivers, Šalčia River, Varėnė river, Vištytis Regional Park.