Effects of flood frequency and bank types on plant species composition in riparian wetlands

Background: This study investigates the impact of flooding rate and bank type on plant species composition in riparian wetlands.Riparian wetlands, which are connected to rivers, provide a unique ecological environment shaped by periodic flooding and water flow, supporting diverse flora and fauna.The flooding rate directly influences plant community structure; flood-tolerant species dominate frequently flooded areas, whereas other species thrive in less frequently flooded zones.Bank type affects soil moisture distribution, influencing plant composition and growth.Soil characteristics were analyzed, and vegetation was surveyed across the upper, middle, and lower sections of banks at 30 sites along the Han River in Korea. Results:The study found that the upper sections of banks where water flows down from the land maintained higher soil moisture content, favoring the dominance of moisture-tolerant species such as Phragmites australis and Humulus japonicus, which consequently reduced species diversity.In contrast, the upper sections of banks with levees that restricted water flow exhibited relatively lower soil moisture content, reducing the prevalence of dominant species such as H. japonicus and P. australis and thereby promoting higher species diversity.Most environmental factors showed no significant differences between the two bank types, except for soil moisture content in the upper section and soil organic matter content and pH in the lower section, which exhibited statistically significant variations (p < 0.05).Soil moisture content, pH, soil organic content, and soil texture were identified through redundancy analysis as key environmental variables influencing plant distribution, with each species responding uniquely to the hydrological and soil conditions shaped by flooding rate and bank type.Conclusions: This study highlights the need for effective levee design and wetland management strategies to promote biodiversity and maintain ecological balance in floodplain ecosystems.