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

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 15261.73 hm², while that of Grade-Ⅲ ecological safety zone increases by 9439.52 hm²; 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.