1980—2018年江苏里下河平原景观格局时空变化及其热点分析

  目的  探讨景观格局时空变化及其冷热点，为区域生态安全与高质量发展提供科学依据。  方法  以江苏里下河平原1980、1990、2000、2010与2018年共5期景观类型数据为基础，采用景观格局指数、景观转移矩阵、景观综合动态度等方法，分析里下河平原近40 a景观格局的时空变化特征，基于热点分析探究景观变化的冷热点区域。  结果  研究区耕地、湖荡湿地和建设用地为优势景观类型，耕地是面积占比最多的景观，但整体上持续减少了1 000.67 km2，湖荡湿地和建设用地面积不断扩张，建设用地扩张面积达679.83 km2，草地和未利用地面积有所减少，林地面积有所增加。近40 a来，研究区各景观类型之间发生了复杂的相互转化，最显著的是耕地与湖荡湿地、建设用地之间的相互转化。研究期间格网景观综合动态度变化幅度为0~5.43%。里下河平原景观变化具有明显的方向性和聚集性，以“东南—西北”方向为主轴发生倾斜，兴化市、高邮市、盐都区及江都区是景观变化的热点区域。  结论  里下河平原景观格局变化显著，景观多样性增加、破碎化加剧，人类活动对景观格局的影响增强。自然湿地恢复政策的实施对研究区景观生态安全产生了积极影响。图4表4参32

Spatial-temporal variations of landscape pattern and hot spot analysis in the Lixiahe Plain of Jiangsu Province from 1980 to 2018

  Objective  With an exploration of the temporal and spatial changes of landscape pattern as well as an investigation of its cold and hot spots, this paper is aimed to provide a scientific basis for regional ecological security and high-quality development.   Method  With landscape type data collected of the Lixiahe Plain, Jiangsu Province over the five periods of 1980, 1990, 2000, 2010 and 2018, an analysis was made of the characteristics of temporal and spatial changes of its landscape pattern in the past 40 years using landscape pattern metrics, transfer matrix and comprehensive dynamic index. Then, an investigation was conducted of the cold and hot spot regions of landscape changes on the basis of hot spot analysis.   Result  Cultivated land, lake wetland and construction land were the dominant landscape types in the study area with the coverage of cultivated land accounting for the largest proportion, but having decreased by 1 000.67 km2 in the past 40 years whereas the areas of lake wetland and construction land increasingly expanded, with the area of construction land increasing by 679.83 km2 and the area of grassland and unused land showed a slightly decreasing trend, while that of forest increased slightly. The landscape types had undergone complex mutual transformations in the past 40 years with those of cultivated land, lake wetland and construction land being the most remarkable with the comprehensive dynamic index of the grid landscape varying between 0 and 5.43% over the study period. The landscape change of the Lixiahe Plain had obvious directionality and agglomeration: the center of change was tilted along the “southeast-northwest” direction, and the hot spots of landscape change were located at Xinghua City, Gaoyou City, Yandu District and Jiangdu District.  Conclusion  The landscape pattern of the Lixiahe Plain underwent significant changes due to the increase of landscape diversity and the intensification of fragmentation and the impact of human activities on the landscape pattern. The implementation of the natural wetland restoration policy had a positive impact on the landscape ecological security in the Lixiahe Plain. [Ch, 4 fig. 4 tab. 32 ref.]