基于网格尺度的保山市中心城区生态安全评价研究

Research on Ecological Security Evaluation of Central Baoshan City Based on Grid Scale

以保山市中心城区为研究对象,基于划分的生态评价网格,应用分离度指数(LDI)、最大斑块占比(LPI)和香浓多样性指数(SHDI)分析保山市中心城区景观格局特征,从景观格局指数和生态安全评价模型对2001-2019年保山市中心城区进行生态安全研究。结果表明:2001-2019年,保山市中心城区景观破碎化程度呈上升趋势,在研究区东部表现最为明显;研究区中部和南部的优势斑块受到外界持续干扰,最大斑块面积持续减小;城市化进程中,研究区土地利用越来越丰富,各斑块类型在景观中呈均衡化趋势分布,主要表现为生产空间逐渐转为生活空间。研究区生态安全属性持续降低:其中Ⅱ级生态安全区面积减少最多,净减少15 261.73 hm^(2);Ⅲ级生态安全区面积增加最多,净增加9 439.52 hm^(2);生态安全在Ⅴ级以下主要分布在研究区西部,由西部逐渐向东部、南部和北部扩散,表现出由单一团状向多团状趋势发展。研究区在2019年首次出现生态安全状态重警区域,说明该区域内部生态系统结构发展极不合理,生态系统服务功能退化严重。

Based on the gridding supervision of ecological environment, the separation index(LDI), the largest patch index(LPI) and the Shannon diversity index(SHDI) were used to analyze the characteristics of the landscape pattern of central urban area of Baoshan City, researches on the ecological protection of it from 2001 to 2009 are carried out from the perspectives of landscape pattern index and ecological security evaluation. The results have shown that during that period, the landscape fragmentation of central urban area of Baoshan City is on the rise, which is especially true in the east;under the continuous influence of external interferences, the areas of dominant patches in the central and southern parts keep decreasing;in the process of urbanization, the land utilization is becoming increasingly diversified;and the land patches are evenly distributed, which is shown as the gradual change from production space to living space;the ecological safety indexes continue to decrease: the area of Grade-Ⅱ ecological safety zone decreases the most with a net reduction of 15 261.73 hm^(2), while that of Grade-Ⅲ ecological safety zone increases by 9 439.52 hm^(2);the ecological safety zones below Grade-Ⅴ are mainly distributed in the west, which are now stretching to the east, south and north. It actually shows a trend from single cluster to multi cluster. The serious warning had been released for the first time in 2019, indicating that in the study area, the structure of ecosystem is extremely unreasonable and the service function of ecosystem is severely degraded.