Factors influencing initial population establishment and habitat expansion of introduced nutrias (Myocastor coypus) in South Korea

Abstract

Biological invasions have increased in recent years, as these are facilitated by traffic networks of human infrastructure. Accidental release from the animal industry is an important cause of biological invasions, and allows for the clear determination of the source of non-native species. Such examples of invasion can be beneficial for studies on the relative importance of local environments by comparing establishment successes from different sources. Nutrias (Myocastor coypus), originally introduced to South Korea for meat and fur production, escaped from local farms into the wild in the late 1990s. Using ensemble species distribution models (ESDM), we assessed 1) suitable habitat conditions for nutrias, 2) establishment success from different source localities after the nutrias' escape from farms, and 3) changes in habitat suitability based on regional climate scenarios. We found that the distribution of nutrias was largely influenced by temperature regime (i.e., minimum temperature during the winter; 44.1 ± 11.4% of variable contribution in the ESDM) and invasion success of nutrias that had escaped from different local farms was also related to the local climate conditions. Escaped nutrias were widely observed around the farms with favorable habitat conditions. Our model predicted a gradual expansion of habitats suitable for nutrias; however, core habitats are isolated by high-mountain ridges and watershed boundaries. National campaigns to prevent translocation between different watersheds are important to control further expansion of escaped nutrias.