The re-colonisation progress of intertidal benthic fauna community in the Changjiang Estuary

The study was carried out in a intertidal flat after ecological engineering at the west of Chongimng Island in January, 2006. Succession plots were disturbed by ecological engineering and Macrobenthos community were damaged severely. Through a re-colonisation field study three main questions were approached: (1) How do different ecological indicators react during the process of recovery? (2) What does grow first during a community succession, biomass or complexity? (3) Can the chosen ecological indicators help in recognising the three proposed forms of growth: biomass, network and information, throughout re-colonisation? Multivariate analysis was performed to examine the convergence of the disturbed plots with the surrounding community during recovery. Shannon Wiener Index, Margalef Index, Pielou evenness, exergy and Specific exergy were applied to characterize the state of the community during the recovery process. Results showed that the replacement of species over time happened associated Macrobenthos community. Species richness increased rather rapidly and species composition was similar in disturbed and undisturbed areas. After 1 month, diversity was consistently higher in the community undertaking recovery. Exergy and Specific exergy provided useful information about the structural development of the community but lacked discriminating power with regard to the informational status of the system. The observations appear to illustrate a case explainable by the Intermediate Disturbance Hypothesis (IDH). Overall, the characteristics of a systems' recovery after disturbance appear to be dependent on the spatial scale of the disturbance. If a disturbed area is small when compared to a contiguous non-disturbed one, complexity (information and network) will recover prior to biomass.