Quantifying the impacts of river hydrology on riparian vegetation spatial structure: Case study in the lower basin of the Tarim River, China

Abstract

AbstractRiver hydrology largely determines the species composition and spatial distribution of riparian vegetation. However, it is difficult to determine the riparian vegetation spatial pattern that is only influenced by river hydrology due to the complex impacts of other influencing factors in field environments. We investigated the spatial structure of riparian vegetation in the lower basin of the Tarim River in hyper‐arid western China, where distinct geomorphic and climatic features exclude the influences of factors other than river hydrological factors on the spatial structure of riparian vegetation. Landsat 8 Operational Land Imager remotely sensed data were used to identify the different vegetation types and obtain the vegetation leaf area index (LAI) in the study area. Our results showed that the overall vegetation LAI exhibited a negative exponential declining trend with distance from the river, but this relationship was different for the different vegetation types, exhibiting a negative exponential relationship for the Populus woodlands and a Gaussian‐type relationship for the Tamarix shrublands. The average width of the riparian vegetation decreased along the river by a negative power function. The average vegetation LAI decreased linearly along the river. The quantitative data we obtained regarding the river‐induced variation in the riparian vegetation cover with the distance from the river channel would particularly be useful for modelling riparian vegetation dynamics and distributions.