Fifty years after introduction: muskrat Ondatra zibethicus population of Khar-Us Lake, Western Mongolia

The first release of the muskrat (Ondatra zibethicus) in the ecosystem of Khar-Us Lake, Western Mongolia, commenced in 1967. A total of 415 individuals were introduced into this watershed until the early 1980's. Subsequently, the distribution of muskrats has expanded exponentially throughout the wetlands of Khar-Us Lake. For example, they are distributed along the Khovd River, the Khovd River mouth, the Dalai Lake and the islands of the Tsagaan River. These habitats are under threat of degradation due to the activities of both humans and domestic animals. The current population of mature muskrats in the Khar-Us Lake is approximately 80,000 individuals. This increased population has had numerous impacts on these ecosystems, suggesting that some measure of control must be established to ensure the population remains sustainable while the ecosystems remain intact. In situations such as this, where an invasive species is inflicting tangible damage to an ecosystem, sustainable harvesting can be necessary for the purpose of regulating their impact. The sustainable hunting of muskrats for their fur is however beneficial to the development of the local economy which in turn strengthens the management plan for the National Park of "Khar-Us Lake".