Emergy-Based Sustainability Evaluation of the Mulberry-Dyke and Fish-Pond System on the South Bank of Taihu Lake, China

The Taihu Lake drainage basin is the birthplace of the Mulberry-dyke and Fish-pond System (MFS), a traditional eco-agricultural system. In 2017, the largest and best-preserved "Zhejiang Huzhou Mulberry-dyke and Fish-pond System" located by the South Bank of Taihu Lake, China was recognized as Globally Important Agricultural Heritage Systems (GIAHS) by the Food and Agriculture Organization of the United Nations (FAO), and its value has been appreciated. As a dynamic heritage, the sustainable development of MFS is a fundamental requirement of the conservation of GIAHS. In this regard, it is necessary to figure out an approach to evaluating the status of its sustainable development. This paper analyzes and contrasts the emergy embodied in the three patterns of MFS over different periods, then constructs an index system of sustainability evaluation involving the production and consumption processes based on that. Finally, it provides the evaluation and analysis. The three patterns of MFS differ in the system structure. In the Ming and Qing Dynasties (abbreviated as Ming-Qing pattern), MFS was an integrated system compromised of mulberry cultivation, silkworm breeding, fish breeding, and sheep breeding, while other patterns exclude sheep breeding, but increase the input of fertilizer, and add the production of mulberry-leaf tea and other local specialties. The results show that the MFS in the Ming-Qing pattern has the highest integrated evaluation index of sustainable development, followed by the traditional MFS pattern and the new MFS pattern employed nowadays. This indicates that the current capability of sustainable development has decreased compared to that in the Ming and Qing Dynasties. The integrated evaluation index regarding the consumption process of the new MFS pattern is higher than the traditional one, suggesting that it needs to promote sustainability in the production process, especially via the utilization rates of renewable resources and wastes.