Large-scale estuarine engineering and estuarine habitat fragmentation of water body in the Yangtze River Estuary
长江河口大型工程与水体生境破碎化

Estuarine habitat, one of basic components of estuarine ecosystems, is a typical marine habitat. Human activities such as large-scale engineering construction in the estuarine comprehensive regulation have an important impact on estuarine ecosystems, resulting in estuarine habitat fragmentation. In this paper, based on the survey and sampling data of 7 habitat indices carried out during May to June, 2002 in the Yangtze River Estuary, we preliminarily studied and analyzed the impact of the first-stage project of Deep-waterway Regulation on habitat fragmentation of estuarine water body. The estuarine water habitats can be subdivided into 3, 2, 3, 3, 6, 4 and 5 patch types for salinity, DO, COM_(Mn), SiO_3-Si, Chl a, phytoplankton and zooplankton, respectively. The seascape diversity(H), dominance index(D)and fragmentation index(C)of 7 indices in water body differed significantly. H of Chl a is the highest with 0.58 and that of DO the lowest with 0.04; D of COD is the highest with 0.30 and that of phytoplankton the lowest with 0.08; C of Chl a is the highest with 0.30 and that of DO is the lowest with 0.05. Except for salinity, the number of patches, H, D and C of DO and COD in water body of the Yangtze River Estuary in May are higher than that in May 1997. Our results showed that the large-scale estuarine engineering has had obvious impacts on the habitat fragmentation of water body in the Yangtze River Estuary, resulting in locally small-scale changes in oceanic water mass. The results from this study suggest that the first-stage project of Deep-waterway Regulation has caused habitat fragmentation and significant impact on seascape diversity of estuarine water body. The patch patterns of estuarine water body are related to local hydrodynamic condition caused by the first-stage project, which deserve for further research.