In plant ecology and environmental remediation, the characterization of riparian plant communities and the influence of environmental factors have been widely discussed. However, the delineation of plant communities from different spatial perspectives is often overlooked, especially in hillstreams. In this study, the Lingshan River is taken as the research area, which is a quintessential hillstream and is characterized by a plethora of hydraulic structures lining its course by 20 weirs. We aim to investigate the multidimensional spatial distribution of riparian plants and their main environmental factors through plant field surveys combined with cluster analysis and redundancy analysis (RDA). The main findings are as follows: (1) In this study, a total of 104 herbaceous species were investigated, distributed among 12 families, in which Poaceae (16.67%) and Compositae (9.65%) showed significant dominance. (2) Plant community delineation was based on the complete linkage clustering. Five plant communities were classified along the longitudinal scale of the river, four plant communities were in the near-water zones, and three plant communities were in the far-water zones. (3) Riparian plant diversity and community distribution in longitudinal and lateral dimensions exhibits significant differentiation. Longitudinally, there was a significant decrease in plant diversity from upstream to downstream. Laterally, the plant biomass in the near-water zone was higher than in the far-water zone, while diversity demonstrated a reverse trend in the midstream. (4) The main environmental factors influencing plant distribution varied for different spatial dimensions. Longitudinally, the physical factor of soil is domination, particularly soil texture, which exhibits the strongest correlation with plant communities. Laterally, the chemical factor of soil is domination, such as soil organic matter and soil nitrate nitrogen content. This study enhances our understanding of the riparian area’s ecology, and provides a scientific basis for plant cover restoration and ecological environment protection, and their management.

Restoring vegetation in riparian zones is regarded as a best management practice in river restoration. Vegetation characteristics and diversity play a decisive role in maintaining ecological function in riparian zones. This study focuses on multi-scale distribution of herbaceous vegetation composition and diversity in riparian zones of three small–medium rivers in northern Zhejiang Province, China, through two years’ field investigations. Meanwhile, the main environmental and hydrological factors were analyzed by principal component analysis (PCA). The results indicated the following: (1) A total of 220 herbaceous plant species belonging to 55 families and 162 genera were recorded, with Poaceae (39 species, 17.73%) and Asteraceae (32 species, 14.55%) being the most abundant families. (2) Significant differences in riparian vegetation biomass and diversity were observed at both the river basin and river segment scales, in which upstream areas always showed higher richness and greater diversity of riparian vegetation. (3) The primary environmental factors influencing vegetation distribution varied with spatial scale: At the river scale, soil organic matter and water nitrogen were key factors affecting vegetation diversity, while riparian vegetation diversity was also influenced by water area. At the river segment scale, aquatic environmental factors exerted a more pronounced effect on vegetation diversity, with total phosphorus and nitrate nitrogen in water being the primary influencing factors. This research provides a theoretical basis for the restoration and sustainable management of riparian ecosystems in the study area and other similar regions.

Due to the multiple benefits of drip fertilization, such as water conservation, fertilizer reduction and environmental protection, it has been widely adopted in orchard cultivation in China. However, the effects of drip fertilization on soil nitrogen in citrus orchards of different ages and their mechanisms are still unclear. Therefore, this study carried out soil surveys in three citrus (Citrus reticulata Blanco) orchards of different ages under two irrigation and fertilizer treatments (NF: normal fertilization; DF: drip fertilization) in Nanfeng City, Jiangxi Province, renowned as the “Chinese Citrus Township”. Soil nitrogen and properties, bacterial communities, N-cycling functional genes and their correlations were analyzed. In the results, soil TN content reduced under DF in the orchard that was 1–2 years old but increased in the orchard that was >10 years old. Soil SN under DF was generally higher and more responsive to tree age, mainly driven by SON. Soil bacterial diversity and composition were influenced by DF, but related to tree age, soil N-cycling showed an “active retention” mode under DF. Soil nitrogen was more related to soil physicochemical properties in the irrigation stage but to soil bacterial factors in the non-irrigation stage. This study can provide a theoretical basis to promote the differentiated application of water–fertilizer integrated technology in citrus orchards of different ages.