## 4 Discussion
Finding the environmental factors that drive their development is important for understanding the requirements for the restoration and stabilization of riparian area ecosystems. The soil in riparian areas is not only affected by plant root growth, but also by the hydrological characteristics of the river. For example, floodplain hydrological conditions significantly affect plant community distribution [43]. It has also been shown that plant growth and biodiversity are inextricably linked to soil conditions, which significantly affect biomass allocation and species diversity in plant communities [44]. Some studies have shown that there is a strong correlation between soil carbon and nitrogen content and plant growth and development, which is somewhat similar to the conclusions reached in this study [45]. At the same time, studies have also shown that nitrogen is one of the elements required in large quantities for plant growth and development and is a key element in the adjustment of ecosystems [44,46]. This is more in line with the findings of this study, which identified that nitrate-nitrogen content is significantly correlated with species development. Soil organic matter promotes the formation of soil structure, raises the temperature of the soil, promotes the growth and development of crops, and improves the soil's fertilizer retention capacity and buffering properties [47]. However, it is worth mentioning that some correlation exists between these two factors, as both are related to soil chemical properties. Furthermore, previous studies have demonstrated significant correlations between soil organic nitrogen content and acidity/alkalinity with climatic factors such as temperature and rainfall [48]. Additionally, from Figure 7, it is evident that 40% of the twelve plant communities exhibit a strong positive correlation with soil nitrate nitrogen. This finding suggests that disturbance factors associated with soil chemical properties play a prominent role in shaping the structure of plant communities in the riparian area. It has been shown that there is a strong positive correlation between soil organic matter and plant growth and development, which is consistent with the findings of this study that typical species have strong positive correlations with soil organic matter [49]. Moreover, the spatial arrangement of each plant community in the sorting space offers valuable insights into their ecological traits. Through the analysis of their spatial distribution and correlation with environmental factors, we can enhance our understanding of the ecological dynamics and interactions in the riparian ecosystem. A comparison of the distribution of plant communities from different spatial perspectives shows that the plant communities divided longitudinally are more affected by physical environmental factors, soil physical properties, and mechanical composition; meanwhile, the plant communities divided according to the lateral distance from water have a higher correlation with soil chemical factors, and in particular, the nitrate nitrogen content, pH value, and soil water content affect the distribution of plant communities in the far-water zones. It has been shown that changes in soil moisture can lead to changes in soil physic-chemical properties such as soil structure (aggregates) and organic matter content [29]. Therefore, in arid areas, soil water content becomes the main environmental factor limiting the growth of plants, which is consistent with the conclusion of this paper. At the same time, soil physical and chemical properties, including soil water content, pH, organic matter, etc., have a certain impact on the species composition and plant diversity of riparian area plant communities. Specifically, soil pH in the riparian area promotes the decomposition rate of soil enzymes [50]. The present study also found that the pH level had a more significant effect on the distribution of plants because it can indirectly increase the species richness and diversity of plant communities through enhancing the soil fertility.