The Relative Roles of Climate, Local Habitat, and Spatial Factors in Shaping Riparian Herbaceous Community Structure Along a Large Temperate River, China

Riparian areas serve as critical hotspots of biodiversity, and understanding the spatial pattern of species distribution is essential for biodiversity conservation. However, the mechanism underlying species distribution remains an unsolved topic in ecology. To address this knowledge gap, we examined the spatial pattern of riparian herbaceous community structure along a large temperate river (i.e., the Liaohe River) in China, and aimed to determine how the relative roles of climate, local habitat, and spatial factors in shaping plant community structure vary across different geographical regions. Our findings indicate that climate, local habitat, and spatial factors jointly influence herbaceous community structure. Specifically, precipitation and temperature significantly affected species richness in most regions of the Liaohe River basin. Notably, precipitation exhibited a negative relationship with species richness along the West Liaohe River, whereas it showed a positive association along the left tributaries of the Liaohe Mainstream. Spatial factors explained a larger proportion of variations in herbaceous community composition than climate and local habitat along the West Liaohe, East Liaohe, and Taizihe Rivers. Although local habitat explained a small fraction of variations in herbaceous composition in most geographical regions, it emerged as key drivers along the Liaohe Mainstream. In conclusion, the relative roles of climate, local habitat, and spatial factors in structuring riparian herbaceous communities were not determined by spatial extent, but were closely tied to the environmental context, including climate and human disturbance.