Abstract: Riparian vegetation is the key factor driving ecosystem function of riparian zone. We analyzed the spatial distribution and quantitative fluctuation characteristics of vegetation in the floodplains of Lingshan River in Longyou County, Zhejiang Province from 2015 to 2019, using TWINSPAN and CCA methods. We constructed a measurement formula of vegetation fluctuation. There were 189 plant species in 158 genera, 53 families and seven plant community types on the floodplains of Lingshan River from 2015 to 2019. The relative water surface elevation was the dominant factor driving vegetation fluctuation. With the increase of relative water surface elevation, plant communities changed from the hygrophyte communities to the mesophyte communities, while the composition changed from herb-dominant to shrub-grass and tree-shrub-grass. The fluctuation of dominant plant populations on the floodplains could be divided into three types: rising fluctuation, declining fluctuation, and compound fluctuation. Vegetation fluctuation had obvious directionality, with annual fluctuation ratio of vegetation on the floodplains ranged from -0.250 to 0.219. Vegetation fluctuation was positive in 2015, 2018, and 2019, and negative in 2016 and 2017. Our results provide a reference for river ecological restoration.

Key words: photosynthetic characteristics, penetration resistance, deep vertically rotary tillage, plow pan, water use efficiency.