Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China

Abstract

Flooding regime changes resulting from natural and human activity have been projected to affect wetland plant community structures and functions. It is therefore important to conduct investigations across a range of flooding gradients to assess the impact of flooding depth on wetland vegetation. We conducted this study to identify the pattern of plant height, species richness and aboveground biomass variation along the flooding gradient in floodplain wetlands located in Northeast China. We found that the response of dominant species height to the flooding gradient depends on specific species, i.e., a quadratic response for Carex lasiocarpa, a negative correlation for Calamagrostis angustifolia, and no response for Carex appendiculata. Species richness showed an intermediate effect along the vegetation zone from marsh to wet meadow while aboveground biomass increased. When the communities were analysed separately, only the water table depth had significant impact on species richness for two Carex communities and no variable for C. angustifolia community, while height of dominant species influenced aboveground biomass. When the three above-mentioned communities were grouped together, variations in species richness were mainly determined by community type, water table depth and community mean height, while variations in aboveground biomass were driven by community type and the height of dominant species. These findings indicate that if habitat drying of these herbaceous wetlands in this region continues, then two Carex marshes would be replaced gradually by C. angustifolia wet meadow in the near future. This will lead to a reduction in biodiversity and an increase in productivity and carbon budget. Meanwhile, functional traits must be considered, and should be a focus of attention in future studies on the species diversity and ecosystem function in this region.

Effects of Water Depth and Phosphorus Availability on Nitrogen Removal in Agricultural Wetlands

“…The results suggest that not only wetland area but also wetland volume may be important for N removal. However, a higher plant production in shallow wetlands [17,[38][39][40] may promote N removal [36,37], which could not be tested in this short-term study. The results suggest that a low availability of P may, in some situations, limit N removal in wetlands receiving drainage water from agricultural fields.…”

“…We suggest that longer residence times in the deep wetlands in this short-term study promoted N removal. However, it is likely that shallow wetlands will successively develop more vegetation than deeper wetlands [39,40], and therefore, that positive effects on the N removal of vegetation in shallow wetlands will become more important in the long run.…”

“…Water depth determines the cover and structure of macrophytes and the microbial growth on surfaces of vegetation in wetlands [17,38]. Specifically, the development of highly productive emergent vegetation is promoted by shallow water [39,40]. Weisner et al [14] suggested that a rational distribution of macrophytes with different water depths in wetlands may promote denitrification processes and decrease the degree of short-circuiting.…”

Application of a Dielectric Measurement Technique for Calculating Water Loss from Two Texture-contrasting Soils Grown with Upland Rice

“…A study by Tilly et al (2015) showed that plant height had a very strong relation to biomass production of rice (R 2 : 0.72 to 0.91) and recommended the variable as a non-destructive estimator for biomass of paddy rice. In particular, the plant height influenced the aboveground biomass significantly as reported by Lou et al (2016), while this biomass could be responsible for evapotranspiration, therefore the plant height presented in Table 2 might explain the variations in soil water loss between two study soils.…”

Study on Electrophysiological Signal Monitoring of Plant under Stress Based on Integrated Op-Amps and Patch Electrode

“…About two-thirds of the land area suffers different degrees of flooding [14]. The waterlogging stress is a kind of water stress, and the water stress includes drought stress (moisture loss) and waterlogging stress (flood).…”