海口市江东新区30年来海岸带城市扩展与生态格局演变

Urban expansion and ecological pattern evolution of coastal zone in Jiangdong New District of Haikou City in the past 30 years

基于GIS和RS技术,在最小累积阻力MCR模型基础上引入不同源地等级的相对阻力因子构建城市扩展生态阻力面UEER模型,并结合水文分析Hydrology模型利用多时相的研究方法对海口市江东新区五个时期(1988年、2001年、2009年、2017年和2019年)的建设用地扩展格局进行动态模拟分析,从生态安全的视角探讨海口市江东新区海岸带城市扩展与生态格局演变趋势。研究结果表明:(1)2018年前研究区重点建设区表现出“摊大饼”式蔓延格局,但在研究时域内重点建设区的面积从49.48 km^(2)增加到61.57 km^(2),建设用地总体上是逐渐集聚的,表现出以重要交通枢纽、现有居民区和商业区为中心向外扩展的趋势。(2)城市扩展是沿着建设用地适宜扩展路径进行的,因受制于生态隔离带并不与相邻建设用地直接相连,由“适宜扩展路径”引导建设用地优化开发,避免建设用地盲目的向外扩展。另外,生态隔离带有逐渐向建设用地渗入,打破了建设用地适宜性区域集中连片的扩展态势。(3)东寨港自然保护区的存在,使得江东新区东海岸以东寨港红树林自然保护区为中心形成的片状区域是生态安全核心区域,虽在相关政策的支持下,研究区的生态风险在一定程度上有所减小,但仍应予以重视及保护。(4)结合研究区实际发展情况,研究区建设用地扩展现象受政策因素影响较大,现有建设用地在禁止建设区和生态恢复区内面积占研究区总建设面积的比重由0.30%增长到15.65%,说明海岸带及其附近的建设用地虽有向生态用地演变的趋势,整体上也逐渐规范化,但生态格局依旧需要优化。

Based on GIS and RS technology, this paper introduces the relative resistance factors of different land grades to build the urban expansion ecological resistance surface model(UEER) on the basis of the minimum cumulative resistance model(MCR). What′s more, combined with the hydrological analysis model, using the multi temporal research method, this paper makes a dynamic simulation analysis on the expansion pattern of construction land in 1988, 2001, 2009, 2017 and 2019 of Jiangdong New District in Haikou, and then discusses the trend of urban expansion and ecological pattern evolution in the coastal zone of Jiangdong New District in Haikou from the perspective of ecological security. The results show that:(1) Before 2018, the key construction areas in the study area showed a "pie spreading" pattern, but the area of the key construction areas in the study time domain increased from 49.48 km^(2)to 61.57 km^(2). Generally, the construction land is gradually concentrated, showing a trend of outward expansion centered on important transportation hubs, existing residential areas and commercial areas.(2) Urban expansion is carried out along the suitable expansion path of construction land. Because it is subject to the ecological isolation zone and is not directly connected with adjacent construction land, the "suitable expansion path" guides the optimal development of construction land to avoid blind outward expansion of construction land. In addition, the ecological isolation zone gradually infiltrates into the construction land, breaking the expansion trend of centralized and contiguous areas of construction land suitability.(3) Because Dongzhaigang Mangrove is listed as a National Nature Reserve, the sheet area formed by Dongzhaigang Mangrove Nature Reserve on the east coast of Jiangdong New District is the core area of ecological security. Although the ecological risk in the study area has been reduced to a certain extent with the support of relevant policies, it should still be paid attention to and protected.(4) Combined with the actual development of the study area, the expansion of construction land in the study area is greatly affected by policy factors. The proportion of the existing construction land in the prohibited construction area and ecological restoration area in the total construction area of the study area has increased from 0.30% to 15.65%, indicating that although the construction land in the coastal zone and its vicinity has a trend of evolution to ecological land and is gradually standardized as a whole, the ecological pattern still needs to be optimized.