Impact of the Disturbances for Forest Grazing on Flora Composition in a Natural Forest

Daegwallyeong is a mountain pass at an altitude of 832 m, which has been designated a conservation area because of its essential role in Korea’s forest ecosystem. Simultaneously, this area is considered a suitable place for forest grazing due to the cool temperature during the summer. Some areas have been converted to grassland for livestock feeding, and the scale has continued increasing. Although livestock in a forest area is more ecofriendly than industrialized facilities, it could impact the native ecosystem, especially in terms of the flora and vegetation. We investigated the changes in flora and vegetation of Daegwallyeong before and after the grassland formation. The total number of vascular plant species changed throughout the survey period. It was decreased by thinning and forest floor removal in 2015. However, it bounced back to the original number in 2016, even after grazing. However, there was a dramatic decrease after the second forest floor removal and 3 months of grazing in 2017. The number of flora slightly increased after the fallow of grazing in 2019, but it did not fully recover. Although the number of flora seemed back to normal, the composition of the flora in 2019 was significantly changed from the forest without disturbance in 2014. First, there was the invasion of naturalized plants such as Taraxacum officinale and Barbarea vularis, as well as ecosystem-disturbing flora such as Carex callitrichos var. nana and Rumex acetosa. Second, the coverage of those species expanded after thinning and grazing. Most importantly, we lost five valuable rare species, Anemone koraiensis, Viola diamantiaca, Chionanthus retusus, Scopolia japonica, and Streptopus ovalis, from the area. Additionally, the ground condition of the area was severely damaged, and plants no longer grow in some areas. The survey and analysis of plants in this study showed the adverse effects of forest grazing practices on rare plants in Daegwallyeong. Forest grazing practices should be carefully conducted to preserve vulnerable plant species and a healthy ecosystem.