## 1 Introduction  
Vegetation has been identified as a crucial factor in the prevention and control of soil erosion [1]. However, the quality and biodiversity of soils in the dominant riparian have significantly declined due to prolonged periods of water erosion and scouring. The presence of vegetation has been shown to increase soil erosion resistance through three different conditions within the soil-root interface: roots undergo tensile, pullout, and shear stresses [2]. Water flooding is a critical environmental factor that influences the survival and development of plants in dominant riparians, affecting light intensity, gas composition, soil nutrients, and other environmental factors essential for plant growth [3]. Under flooded conditions, the presence of water bodies obstructs direct contact between plants and the atmosphere, leading to a substantial reduction in the gas content and gas exchange rates of submerged plants [4]. This isolation from the external gaseous environment subject plants to prolonged anoxic conditions and low light levels, which inhibit their respiration and photosynthesis, ultimately resulting in adverse effects on plant growth. Compared with woody vegetation, herbaceous vegetation is more responsive to environmental changes [5]. Therefore, incorporating the ecological processes associated with these types of vegetation into research and methodological planning is essential [6]. The water level of the Three Gorges Reservoir fluctuates significantly on the basis of the reservoir's operational mode. This variation leads to a period of exposure from April to September, followed by a water storage phase, resulting in a substantial fluctuation zone with a vertical height of 30 m [7; 8]. The environmental conditions within this zone change drastically, while a limited number of dominant plant species can survive, most plants become submerged and decompose, releasing nitrogen, phosphorus, and mercury into the water [9]. This process creates a risk of environmental damage and indicates a certain degree of ecological vulnerability [10]. Changes in the vegetation in the dominant riparian affect not only buffering, filtering and especially the connectivity functions of the reservoir banks in the Three Gorges Reservoir area, but also the aesthetics of the environment and changes in ecological communities [11; 12]. The original plants have difficulty tolerating prolonged flood stress in winter. Coupled with the summer recession period, the plants in the dominant riparian are exposed to a large amount of sunlight and undergo a certain degree of drought stress, resulting in a large area of plant recession in the reservoir area and a decrease in the biodiversity of the reservoir area; The structure of the plant community in the reservoir area is damaged and the structural community gradually becomes homogeneous. Soil erosion is promoted and there is serious land degradation and deterioration of the landscape, which in turn poses potential hazards related to shallow landslides and debris flow phenomena [13]. This study was conducted to investigate the relationship between changes in plant growth capacity and the soil fixation performance of the root systems of the dominant species in the dominant riparian plants under various flooding durations. Additionally, it aims to comprehensively evaluate the most temporally suitable areas for each plant under different flooding conditions. The individual mechanical properties, soil root content, root-soil interface characteristics, root distribution patterns, and other factors of roots within the root-soil complex are the primary influences [14; 15; 16; 17]. Research has demonstrated [18; 19] that variations in root distribution patterns, including combinations of horizontal, vertical, inclined, intersecting, and mixed alignments, have distinct effects on root strength.