Distribution patterns and vulnerability of stoneflies (Plecoptera: Insecta) in South Korean streams with conservation perspectives

Abstract

Biodiversity loss and conservation are major issues at global and regional scales. Plecopteran species have limited distribution areas and are vulnerable to environmental changes. In this study, we evaluated the distribution patterns and environmental characteristics of plecopteran assemblages in South Korean streams to consider the conservation of plecopteran diversity. We used plecopteran assemblage data with environmental data including 32 environmental variables in six categories (geography, meteorology, land use, substrate composition, hydrology, and water quality) surveyed at 412 sampling sites distributed on a nationwide scale in South Korean streams. Self-organizing map classified sampling sites into seven clusters according to the similarities of assemblages. Non-metric multidimensional scaling (NMDS) was used to characterize the relationship between assemblages and abiotic environmental variables. The abundance of 32 plecopteran taxa recorded in the dataset displayed a positive relationship with the number of their occurrence sites, and most species, including the dominant ones, had low abundances in limited distribution areas. More than 78% (25 out of 32) of the recorded plecopteran species were listed in the Korean Red List of Threatened Species, including 17 taxa in the least concern category. The NMDS results presented the habitat preference of species, and the major influential factors from six environmental categories were elevation, maximum temperature in July, proportion of forest in land-use type, proportion of cobbles in substrate, proportion of riffle in flow condition, and turbidity in physicochemical water quality. The results revealed that plecopteran species were diverse and abundant in cold and undisturbed running water on rocky substrates near mountain forests. The dominant species generally displayed similar habitat conditions. However, their habitat preferences varied depending on the species, with different sensitivities and responses to temperature and hydrological flow conditions. Finally, our results revealed that the plecopteran species in South Korea are mostly vulnerable and endangered, and extensive protection policies covering the stream channel and the surrounding areas are required to preserve their biodiversity.