ESTIMATION OF THE CARRYING CAPACITY OF YANGTZE FINLESS PORPOISE (Neophocaena asiaeorientalis asiaeorientalis) IN TIAN-E-ZHOU OXBOW BASED ON LINEAR FOOD NETWORK MODEL

A food network model of the Tian-E-Zhou Oxbow ecosystem in the Yangtze River was established by combining fishery resource data with other aquatic biological data. The ecosystem can be divided into seven discrete trophic levels, and nutrient flow occurs mainly between the trophic levels I-V. The average material transfer efficiency of each trophic level was 10.5%, there were no obvious key species in the system, and large aquatic plants had the largest key index (-0.173). The matter and energy recirculation ratio in the system was low, while the values of other indicators such as system connection index (CI), system omnivore index (SOI), Finn's cycle index and Finn's mean path length were all at a low level, indicating that the Tian-E-Zhou Oxbow ecosystem was at an early stage of development. Finally, based on the food network model, the environmental carrying capacity of the Yangtze finless porpoise in the Tian-E-Zhou Reserve was calculated as 0.207 t/km(2) , counting about 89 individuals.