Abstract

Invasive rodents are significant issues for the conservation and management of habitats, particularly in island areas. Numerous studies have indicated that invasive rodents on islands directly or indirectly influence native plants and animals negatively. Consequently, many countries have made efforts to eradicate invasive rodents primarily using poison. However, these efforts have led to additional problems, such as the mortality of native animals due to intoxication. Understanding the habitat usage of species in local areas is essential for effective population management. So, we investigated the habitat usage of the invasive brown rat Rattus norvegicus on an uninhabited island. From October 2019 to November 2023, we surveyed field signs of brown rats on Yuksan Island, South Korea. To examine the interactions among habitat factors and brown rat abundance, we calculated 6 valuables including the density of black-tailed gulls during the breeding season, normalized difference vegetation index (NDVI) for spring, summer, and fall, elevation, and slope. The results of the stepwise regression model revealed a strong correlation between the density of brown rat field signs and NDVI in summer. Additionally, elevation, slope, and NDVI in fall were correlated with brown rat abundance. The habitat factors related to brown rat abundance were associated with the availability of food resources and the quality of shelter, which is influenced by vegetation coverage, prevention of drowning, and species-specific behavior.