JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2019, Vol. 62 ›› Issue (03): 107-115.doi: 10.3969/j.issn.1000-2006.201805076

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Ecological security dynamics and trend forecast of coastal wetlands in Hangzhou Bay

LI Nan1,2, LI Longwei2, LU Dengsheng2,3, ZHANG Yinlong1*, WU Ming4   

  1. 1. Co-Innovation Center for the Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; 2. Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration of Zhejiang Province, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China; 3. School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China; ...
  • Online:2019-05-15 Published:2019-05-15

Abstract: 【Objective】 Due to constant anthropogenic disturbance, coastal wetlands of China have been suffering from increasing ecological problems, posing a serious threat to regional sustainable development. It is crucial to clarify the ecological security status and trends of coastal wetlands. For effective management of wetlands and regional sustainable development, the ecological security status of the coastal wetlands in Hangzhou Bay was evaluated and predicted. 【Method】Based on the driving force-pressure-state-impact-response(DPSIR)conceptual model, 46 indicators reflecting the ecological security of the Hangzhou Bay coastal wetlands were selected to develop the ecological security assessment system. Then, these indicators were quantified by remote sensing data, wetland observational data, geographic ancillary data, and socioeconomic statistics. The indicators were normalized as appropriate and the weight of indicators was calculated by entropy methods. A weighted judgment matrix was established to calculate the positive and negative ideal solutions of each indicator. According to the distance between an indicator and the ideal solution, the closeness Ci(i.e., the ecological security value)was calculated and classified into five levels: extremely vulnerable, vulnerable, warning, relatively safe, and safe. The ecological safety values of 2000, 2005, 2010 and 2015 were calculated separately, and the value of 2020 was predicted by the grey prediction model GM(1, 1). 【Result】The ecological security values in 2000, 2005, 2010 and 2015 were 0.413, 0.382, 0.287 and 0.582, respectively. The security level deteriorated from the warning level to the vulnerable level, and returned to the warning level, showing an upward trend after the decline. From 2000 to 2005, large areas of coastal wetlands were occupied due to rapid urban expansion, coupled with increased pollution loads on wetlands, causing the ecological security value to reach the level of vulnerability. From 2005 to 2010, the region maintained rapid economic development under the guidance of policies. As development of the Hangzhou Bay New District intensified, the wetland area was continuously reduced, along with the ecological security value. From 2010 to 2015, the ecological value of wetlands was widely recognized, and a number of wetland protection policies were promulgated by the central and local governments. As environmental protection investment increased, and the pollution load decreased, the ecological security of wetlands has improved. The weights of indicators calculated by the entropy method showed that wetland protection rate, landscape diversity index, domestic sewage discharge, atmospheric regulation, long-term mechanism construction, carbon sequestration, cultural and educational research, population growth rate, tourism and leisure, per capita GDP, industrial emissions, and water conservation were the main factors affecting the ecological safety of coastal wetlands in Hangzhou Bay. In the DPSIR model of the Hangzhou Bay coastal wetlands, the “driving force” has always been in a warning situation, while “pressure” increases from a safe to extremely vulnerable state. Its “state” is not optimistic and the “impact” is basically in a warning state. The local “response” for wetland ecological has grown from scratch and has steadily improved, effectively improving the overall ecological security of coastal wetlands. The gray prediction model GM(1, 1)predicted that the ecological security value of the coastal wetland in 2020 will be 0.697, which is a “relatively safe” state. 【Conclusion】The deterioration of ecological safety of coastal wetlands mainly resulted from rapid economic development, urbanization, and pollution. With extensive attention of the government and the public to the wetlands, the investment in environmental protection has increased, and a long-term mechanism for wetland protection has been established. However, although the ecological security of the wetland has gradually improved, it is still in a security alert state. Overall, with the increased wetland protection, it is predicted that the ecological security status of the coastal wetlands in Hangzhou Bay will further improve in 2020 and will be upgraded to a safe state.

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