Wave attenuation by flattened vegetation (Scirpus mariqueter)

Abstract

With the capacity to reduce wave energy and trap sediment, Scirpus mariqueter has become an important native species of annual grass for ecology restoration at the Yangtze Estuary in eastern China. Due to seasonal variances of biophysical characteristics, S. mariqueter usually bends and breaks in winter, resulting in flattened stems that may reduce its wave attenuation capacity. To investigate the effects of vegetation flattening on wave attenuation, a set of flume experiments were conducted for flattened and standing vegetation under different wave conditions. The model vegetation was designed to represent the wilted S. mariqueter collected in winter with dynamic similarity. Results showed that the wave damping coefficient for flattened vegetation (βF) was 33.6%-72.4% of that for standing vegetation (βS) with the same vegetation length. Both βF and βS increased with wave height but decreased with water depth. A wave attenuation indicator (WAI) was defined to generate empirical formulas for βS and βF as well as their ratio βF/βS. The empirical formulas were then applied to modify the existing standing vegetation-based wave attenuation model for flattened vegetation and performed successfully. Understanding the wave attenuation characteristics of flattened vegetation is essential for the management of ecological restoration and coastal protection.

The above and the belowground nitrogen allocation strategy of Scirpus mariqueter based on 15N isotope tracing along an elevation gradient and its significance for coastal wetlands restoration

“…Its elevation ranges from 2.00 to 5.00 m and experiences irregular semidiurnal tides (He et al., 2023; Wei et al., 2019). The dominant vegetation includes S. mariqueter , P. australis , and S. alterniflora (Ma et al., 2023). The high‐tide zone near the embankment is mainly characterized by S. alterniflora and P. australis , whereas the mid‐tide zone is dominated by S. alterniflora and S. mariqueter (Xing et al., 2022).…”

“…The wetland has a subtropical monsoon climate with an average annual precipitation of 1222.20 mm, average annual temperature ranging from 15 to 16 • C. Its elevation ranges from 2.00 to 5.00 m and experiences irregular semidiurnal tides (He et al, 2023;Wei et al, 2019). The dominant vegetation includes S. mariqueter, P. australis, and S. alterniflora (Ma et al, 2023). The high-tide zone near the embankment is mainly characterized by S. alterniflora and P. australis, whereas the mid-tide zone is dominated by S. alterniflora and S.…”

“…Scirpus mariqueter , a dominant species of coastal wetlands in China (Zhao et al., 2019), provides ecological functions such as wave attenuation, promotion of sedimentation, and erosion resistance (Ma et al., 2023; Zhao et al., 2023). Additionally, it provides essential ecological services by providing food and habitat for numerous birds and benthic organisms (Gan et al., 2009; Li et al., 2009; Tao et al., 2018).…”

Physical Experimental Study on the Wave Reflection and Run-Up of a New Ecological Hollow Cube

“…The ecological performance of breakwaters can be improved by increasing the biomass on the surface of the breakwater by planting coastal plants in planting grooves. However, it may take considerable time for the coastal plants to grow fully [30][31][32][33]. It is therefore necessary to study the stability of the blocks when no coastal plants are planted.…”