Variations in herbaceous vegetation structures and vegetation–environment relationships from floodplain to terrace along a large semi‐humid river

Abstract

Riparian zones along semi‐humid rivers have significant lateral gradients of water, leading to the lateral pattern of riparian vegetation. However, less is known about the determinants of herbaceous vegetation structures between floodplain and terrace in semi‐humid region. The study was designed to assess the variations in herbaceous vegetation composition, species diversity, and vegetation‐environment relationships from floodplain to terrace. Fifty sampling lines that equally distributed in floodplain and terrace were established to collect herbaceous vegetation and corresponding environmental data. Results showed that soil moisture in floodplain was significantly higher than that in terrace, and herbaceous vegetation compositions shifted from hydric to mesic to xeric as soil moisture decreased. Phragmites australis and Artemisia selengensis were dominant species in floodplain, whereas Ambrosia trifid, Metaplexis japonica, Humulus japonicus, Glycine soja, Artemisia lavandulaefolia and Setaria glauca were dominant in terrace. Species diversity increased from floodplain to terrace and from upstream to downstream. Substrate and bank stability, rather than water availability, were the significant environmental drivers of herbaceous vegetation structures in water‐rich floodplain. However, herbaceous vegetation structures were mainly determined by water gradient and human disturbance in water‐poor terrace in semi‐humid region.

Remote sensing assessment of anthropogenic and climate variation effects on river channel morphology and vegetation: Impact of dry periods on a European piedmont river

“…These uncertainties in estimating river width do not significantly influence the outcomes reported here, which are in line with previous investigations performed in other regions worldwide. For example, Xia et al (2018) studied herbaceous vegetation in a semi‐humid river in China by means of in‐field information. Their research shows that, in the case of sandbars and floodplains with low bank stability, which is typical of sandy large rivers like the Po, erosive phenomena associated with floods can disturb or even interrupt the process of vegetation succession, reducing the growing period and the plant diversity and density covering the investigated areas.…”

Insights from long-term variations in gravel riverbed topography as an indicator of vegetation–morphology interactions

“…Flooding shapes the fluvial landforms and habitat gradients for the establishment and development of riparian vegetation [1][2][3][4][5]. Consequently, the flow regime is critical in the formation of plant communities [6][7][8][9][10], seed banks [11][12][13] and nutrient dynamics [14][15][16][17][18]. Riparian vegetation consistently adjusts to flood disturbances and sedimentation process (erosion and deposition of sediments) driven by the flooding history to maintain a dynamic equilibrium, with new conditions correlated with the elevation relative to the river water level [19][20][21][22][23][24].…”