This study was carried out to clarify the response of butterfly communities on forest degradation in the Gwangneung Forest, Korea. We monitored butterfly communities with varying degrees of human activities by conducting a line transect twice a month in 2011. A total of 70 species and 4676 individuals of butterflies were observed in four sites: natural forest (NR), two plantation forests, and the Korean National Arboretum (AR). The result on niche breadth, habitat breadth and habitat type of butterfly was not consistent with our predictions. Species richness of habitat type was only significantly different between NF and AR. Species diversity was significantly different among sites. Butterfly diversity associated with landscape patterns based on aerial photographs supported a mosaic concept. A forest management plan to conserve butterfly diversity in forests is necessary to maintain various habitats and to ensure that grasslands are protected.