Identification of Environmental Factors Influencing the Population of Endangered Epilobium hirsutum L. in Korea

<i>Epilobium hirsutum</i> has been identified as a Class II endangered species in Korea. Therefore, there is an urgent need to develop habitat conservation and improvement strategies for the protection of <i>E. hirsutum</i>. In this study, we aimed to evaluate the environmental characteristics of <i>E. hirsutum</i> habitats and identify key environmental factors influencing the population size. To this end, we conducted field surveys and performed a spatial data analysis to collect data on 38 environmental characteristics associated with the population size of <i>E. hirsutum</i>. We performed factor and path analyses to identify the environmental factors influencing the population size and the correlations between the population size and environmental factors. The common factors identified in both analyses were the average temperature in March, available P, soil pH, and soil humidity. Therefore, to manage <i>E. hirsutum</i> habitats or create alternative habitats, areas with a low air temperature and high soil moisture must be selected. It is necessary to remove tall plants and amend soils with alkaline fertilizers containing P. Additionally, it may be effective to implement a management strategy that induces vegetative propagation and seed germination by replacing agricultural waterways made of concrete with those made of rock and soil.