## 1 Introduction  
The distributional characteristics of riverine riparian plant communities, as well as the biomass and diversity of those plants, have been the primary focus of research aimed at restoring riparian area ecosystems [1]. The stream's riparian area, commonly referred to as the riparian buffer zone, is the transitional zone between land and water along the river interface. This zone exhibits unique characteristics, dynamics, and edge effects, making it a critical source of terrestrial and aquatic species, and serving as an essential wildlife habitat. Moreover, the research has demonstrated that the community structure and succession of plants in riparian areas can significantly influence the heterogeneity of hydrological processes [2]. The plants that thrive in riparian areas play an additional distinct role in the landscape through serving as a transitional medium between terrestrial and aquatic ecosystems. Such plants exhibit specific ecological adaptations, and serve as vital components for the overall functioning of the ecosystem [3]. At the same time, plants serve as a crucial component of the riparian area ecosystem, playing a vital role in safeguarding watershed stability, preventing water quality degradation, stabilizing the area, and preserving ecological diversity both within the riparian area and along the river [4; 5]. The seasonal fluctuations in water levels within the riparian area led to variations in environmental factors such as light availability, water pressure, and oxygen levels. These fluctuations impose significant constraints on the growth, development, photosynthesis, and respiration of plants. Consequently, a series of changes occur in the distribution of plant communities within the zone, including alterations in distributional characteristics, species composition, species richness, abundance, coverage, and ecological functions [6]. From various perspectives, the riparian area's plants and soil play an indispensable role in regulating ecosystem processes. Therefore, studying the distributional characteristics of riparian plants and soil is highly significant for assessing the functionality of natural ecosystems and in facilitating the restoration of the riparian area plants. The unique distributional characteristics of plant communities align with the gradient features of the surrounding environment, encompassing aspects such as species composition, species richness, dominant species types, biomass structure, and plant cover [7]. When evaluating the plant structures of riparian areas, plant diversity has served as a widely adopted quantitative measure by scholars in the field of plant ecology [8]. The differences in plant diversity across various plant communities may reflect their growth and adaptive characteristics, as plant diversity can be influenced by a variety of environmental factors that impact the distributional characteristics of these communities [9]. Furthermore, the distribution of biomass within a plant community significantly influences a range of ecological functions [7]. Despite the significance of these functions in ecological studies of riparian areas, only a limited number of studies have examined the biomass of major plant communities within riparian areas. Moreover, there are relatively few explorations of the relationship between soil properties and plants in riparian areas. Additionally, community biodiversity serves as a quantitative indicator of species composition, providing insights into the overall ecosystem structure. Since 1990, it has been suggested that prolonged water level inundation periods lead to reduced plant diversity, while fluctuating water levels contribute to a comparatively higher plant diversity [10]. Simultaneously, researchers have observed both positive and negative relationships between community biodiversity and soil properties. Consequently, further efforts are required to delve into the intricate relationships between plants and riparian area soils.