基于土地利用变化模拟的生态风险动态评价

Ecological Risk Dynamic Assessment Based on Simulation of Land Use Change

以松滋市2000年和2010年LandsatTM影像为基础，利用CA—Markov模型并引入土地利用总体规划限制因素，预测松滋市2020年土地利用情况。构建土地利用生态风险指数，运用4km×4km的网格模型采样，采用普通克里金插值法进行插值，引入密度分割法进行归一化等级划分，利用GIS工具进行空间叠加分析并制作土地利用生态风险分级图，实现土地利用变化生态风险动态评价，揭示生态风险变化趋势。模拟预测及评价结果显示：①松滋市2000～2020年土地利用结构发生较大变化，耕地、水域和未利用地面积减少，林地和建设用地面积增加。②土地利用生态风险呈逐步升高趋势，由2000年的21．95升高到2020年的88．53，分布以中部及南部较高，西部及东北部较低。③2000～2020年分级结果主要以低风险、较低风险及次中风险为主，特高风险区域逐渐增多，生态风险等级以中心城区为中心呈圈层分布，且距离越远生态风险等级越低。

Based on the data of Landsat TM images of Songzi city in 2000 and 2010, by using CA - Markov model and taking the factors of the land use planning into consideration, the land use patterns and the spatial distribution in 2020 were forecasted. The eco - risk was conducted based on the land use change, the eco -risk plots of 4km × 4km were applied. The maps of the spatial distribution of ecorisk and eeo- risk level were designed, obtained by using the eco -risk plots, ordinary Kriging, normalization methods of density slice and spatial overlay analysis by GIS, which to realize the eco - risk dynamic assessment of land use change and reveal the trend of eco - risk change. The conclusions from the Simulation of land use change and the eeo - risk dynamic assessment showed that： 1 ） The land use change was great between 2000 and 2020 in Songzi city. The area of cropland, waters and unused land de- creased, the area of forestland and construction land increased. 2） The eco - risk of land use change was increasing trend and in- creased from 21.95 to 88.53 between 2000 and 2020. The high eco - risk was in the central region and south region, the low was in the west region and the northeast region. 3 ） Between 2000 and 2020, the area of eeo - risk level was mainly in low - risk, inferior - risk and weakly medium - risk and the strongly high - risk area gradually increased. The eco - risk level was a circle distribution and as the distance from center city was farther the eco - risk level of the area was lower.