Integrity evaluation and dynamic simulation of Xisha coral reef ecosystem

Taking Xisha coral reef ecological monitoring area as an example, from the perspective of ecosystem integrity, combined with the multiple feedback effects of coral reef functional groups and environmental changes, this paper constructs a dynamic diagnosis model of Xisha coral reef ecosystem by using the method of system dynamics. The development trend and evolution mechanism of ecosystem integrity of the ecological monitoring area in 2010-2050 were analyzed through the simulation process of basic scenario and typical interference scenarios(fishing activity, terrigenous deposition, and crown-of-thorns starfish outbreak). The results show that:(1) the integration of system dynamics and ecosystem integrity assessment method provides a feasible method for the quantitative study of coral reef ecosystem integrity.(2) The changes in the cumulative effects of the various effect indexes of the coral reef ecosystem are the most obvious. From 2010 to 2050, the index will increase by 17.2, with an average annual growth rate of about 1.2%. The comprehensive integrity index has steadily increased in fluctuations, and the degree of coral reef damage has changed from damage to medium and low damage.(3) The ecosystem integrity of coral reefs in different states is different at different stages of their evolution, and this difference is usually amplified over time.(4) In any case, the coral reef ecosystem has a certain ability to recover, especially in the stage of release and reorganization of the system evolution(2035-2040). The research results provide a theoretical reference for the analysis of the overall evolution process of the Xisha coral reef ecosystem, and also provide an important basis for the subsequent research on the adaptive restoration theory of the coral reef ecosystem in China.