基于灾变理论的盐城市土地生态安全评价研究

土地生态安全关系到区域的可续发展。以压力 状态 响应模型与灾变理论相结合，根据盐城市的土地利用特点，分别从社会、经济和生态环境方面构建土地生态安全评价指标体系，分析盐城市2002～2011年的土地生态安全变化情况，找出其中的问题，能为盐城市土地利用可持续发展提供理论依据和参考价值。研究表明：盐城市土地利用生态安全等级除了2003年和2007年为安全等级外，其余8 a均为中等安全、不安全和极不安全等级，而且基本呈逐年下降趋势；人口、环保投入和城镇化是导致盐城市土地利用生态安全等级下降的重要影响因素，这种现实状况应该引起政府相关决策部门的高度重视，最后提出了几点建议

ASSESSING LAND ECOLOGICAL SECURITY IN YANCHENG CITY  BASED ON CATASTROPHIC THEORY

Land is the foundation ofglobal survival and development Land ecological security is related to regional sustainable development The land ecosystem plays a very important role in social economic progress at regional, national, and international scale The land ecosystems of Yancheng city have become highly stressed and dysfunctional due to the continuous, excessive exploitation and utilization of land resources In this regard, there is considerable need for methods and indicators to diagnose the state of land ecosystem for prompting ecological restoration, management and regulation A catastrophic model for land ecological security assessment combined with the pressure state response （PSR） model framework was developed in this paper to overcome the disadvantages in subjectivity and complexity of the currently used assessment methods Based on the actual land use in Yancheng city, the paper established the ecological security of land index system from perspectives of economy, society and ecological environment The catastrophic assessment index system was divided into hierarchical sub systems under the pressure state response framework The catastrophe model integrated multiple assessment indices of land ecological security according to the inherent contradictions and relative importance of indices without calculating weights Specifically, membership degree of higher level index was calculated based on the membership degrees of lower level indices that were subjective to suitable model, such as cusp, fold, swallowtail and butterfly model The purpose of this paper is to judge the degree of land ecological security in Yancheng city from 2002 to 2011 via catastrophic theory and PSR model and find the inherent issues to make sure of sustainable development of this region The results showed that among the ten years, the value of pressure, state, response and synthetic about land ecological security was evaluated as safe in the year of 2003 and 2007, then in the year of 2002 and during 2004-2006 was at middle level, then the degree of land ecological security during 2008-2009 was insecure and very insecure from 2011 to 2012, which showed that ecological security level and circumstance of land use in Yancheng city continually decreased During this period, the land use pattern of Yancheng was under the tremendous pressure from the conflict between the rapid urbanization, economic development and the conservation and rehabilitation of eco environment All these imply that land ecosystem conditions are not optimistic for Yancheng city and such situation should draw the high attention of related government departments There are some factors that demographic, the invest ration to protect environment and urbanization rate has the most important influence on the land ecological security of Yancheng city Generally, The calculation procedure presented in this paper does not require a high level of technical expertise to determine the membership degree, making it simple and operational Being applicable to similar land ecosystems, the catastrophic model is thus believed to provide an alternative approach to land eco security assessment This paper emphasized the impacts of human activity on land ecological security of Yancheng city and put forward suggestions concerning the adjustment or optimization of land use pattern and improvement of the technical system for eco security assessment based on regional overall planning from 2011 to 2030, which would have wide application prospective in the future