Comparative Analysis on Environmental Adaptability of Two Types of Bank Stabilization Structures along the Middle and Lower Reaches of the Yangtze River

With the aim to prevent channel incision and migration and provide protection at the riverbank, a series of ecological bank stabilization projects have been carried out in the middle and lower reaches of the Yangtze River. In this study, nine ecological bank stabilization areas using two different techniques, Steel mesh gabion (Type 1) and Chain-type bricks (Type 2), were compared in terms of environmental adaptability on the basis of the survey data of vegetation and substrate. There were no significant differences between the two types of dominant species before and after the flood season. Annual or biennial herbaceous plants had clear spatial competitive advantages while perennial herbs had clear temporal competitive advantages. While Type 1 was better than Type 2 in overall vegetation restoration and growth, Type 2 was more sensitive to periodic flood disturbance. Redundancy Analysis was used to determine the main environmental impact factors that caused differences on biotic indices of the two types. The clay content in the substrate was an important factor affecting vegetation cover and diversity for Type 1 while the substrate nutrient composition was important for Type 2. Generally, Type 1 presented stronger environmental adaptability in channel regulation projects.