Landscape ecological risk assessment in the Taihu region based on land use change

Abstract

在GIS和RS技术支持下, 以遥感数据和土地利用数据为基础, 以行政区划为评价单元, 定量分析太湖地区1990-2008年土地利用变化及其转化关系;从土地利用变化和景观结构角度构建景观生态风险评价模型, 定量评价了研究区内景观生态风险的时空动态变化特征.结果表明:太湖地区景观生态风险分布与区内土地利用方式和强度具有较高关联.景观生态风险整体呈上升趋势, 高生态风险区范围不断扩大;受自然特征和社会经济发展影响, 景观生态风险空间分异显著, 较低风险区主要分布于以苕溪为主的山地丘陵区, 中等风险区主要分布于农业发达的平原区, 较高风险区及高风险区主要集中于沿湖经济发达区.不同区域景观生态风险来源存在一定差异, 各用地类型对生态风险的贡献率亦不尽相同, 就全区而言, 景观生态风险主要来源于耕地和建设用地, 但随着社会经济不断发展, 来自水域和林地的生态风险比例越来越大;The quantitative analysis of the land use change and its transformation relationship in the Taihu region during 1990-2008 was put forward,using GIS and RS technologies, based on the remote sensing data and land use data, taking the administrative di-vision as the assessment units.The assessment model comprising a landscape disturbance index and a land use sensitivity index was established on the base of land use change and landscape perspective to assess the landscape ecological risk characteristics of tempo-ral and spatial change in study area.The results showed that the distribution of ecological risk had higher associated with the inten-sity and pattern of land use change.As a whole, the landscape ecological risk had been rising in the past 18 years;the area of high ecological risk was expanding.Due to the physical characteristics and social economy,the spatial variation of landscape ecological risk was significant.The low risk areas distributed mainly in the hilly and mountainous areas,the medium risk areas was mainly in the agriculture developed plain area,and the higher and highest risk areas distributed at the economically developed areas around the lake.The sources of landscape ecological risks were different, and variable land use types also had different risks.The farmland and construction land were the main risk source of the whole region.As the regional development, the ecological risk from the water and woodland were increasing steadily.