Inventory of vascular plants and conservation-related taxa in pure Quercus mongolica stands in Gangwon-do, South Korea

Pure Quercus mongolica stands are a major component of temperate deciduous broad-leaved forests in South Korea and provide important habitats for vascular plant diversity. Although Q. mongolica forests have been widely studied in terms of community structure, succession and relationships with environmental factors, large-scale plot-based floristic information focused specifically on stands in which Q. mongolica dominates the canopy layer remains limited. This study aimed to document the vascular flora of pure Q. mongolica stands in Gangwon-do and to provide baseline information for floristic diversity assessment, long-term monitoring and conservation management using plot-level occurrence data. Field surveys were conducted from 2019 to 2023 across 1,098 plots established in representative pure Q. mongolica stands. For each plot, vascular plant occurrence data were compiled and selected environmental characteristics of the plots were summarised. The identified taxa were classified according to taxonomic rank and conservation- and management-related categories, including Korean endemic plant taxa, endangered wild plant taxa, Red List plant taxa, floristic target plant taxa, alien plant taxa and ecosystem-disturbing plant taxa. A total of 594 vascular plant taxa were recorded, comprising 103 families, 288 genera, 539 species, 45 varieties, seven subspecies and three forms. The dataset included 20,906 plot-level occurrence records. The families with the highest numbers of taxa were Asteraceae, Rosaceae, Liliaceae, Ranunculaceae, Poaceae and Fabaceae. The number of taxa per plot ranged from 5 to 55, indicating variation in local taxon richness amongst plots of pure Q. mongolica stands. Conservation- and management-related taxa included 32 Korean endemic taxa, one Class II endangered wild plant taxon, 21 Korean Red List plant taxa, 172 floristic target plant taxa, seven alien plant taxa and two ecosystem-disturbing plant taxa. The floristic target plant taxa consisted of 42 Grade I, 44 Grade II, 57 Grade III, 24 Grade IV and 5 Grade V taxa. In addition, 85 taxa listed on the IUCN Red List were identified. These results show that pure Q. mongolica stands in Gangwon-do contain diverse vascular plant assemblages and may serve as habitats for taxa of conservation and phytogeographical interest. The plot-based floristic inventory presented here provides baseline information for biodiversity assessment, long-term monitoring and conservation management of Q. mongolica -dominated temperate deciduous broad-leaved forests in Korea. By linking plot-level occurrence records with environmental metadata, the dataset can support future comparisons of floristic composition amongst Q. mongolica forests.