| In recent years,with the intensity and the scale of human activities expands unceasingly which causes the destruction of the ecological environment and makes the regional ecological security is deteriorating.The ecological environment in the Mountain-Plains transition zones are fragile and cause natural disaster easily.In China,there is not enough attention to this problem and lacks of deep discussion of this kind of regional ecological security.So,It is significant to strengthen the research in the ecological safety of Mountain-Plains transition zone.The present study combined with the program of the National Natural Science Foundation of China.And use the five administrative regions in the Mountain-Plains transition zones in Chengdu as the study zone which include Pengzhou,Dujiangyan,Chongzhou,Dayi and Qionglai.The author selected the remote sensing images from2000,2007,2008 and 2015 as the data sources.The study is based on P-S-R model to build a ecological security evaluation index system for the research area.And using remote sensing and GIS to rasterize the 20 indexes.After that the spatial averaging technique by weight value will be used on it to get the ecological security dates of the transition zones from 2000 to 2015.Then,the author analysis the transition zones' ecological security situations from two scales: pixel and administrative regions.At last,The Moran's I,Getis-Ord General G and Getis-Ord Gi* from ESDA and the index of the Local Moran's Ii will be used to analyze the transition zones' ecological security situations.The results of the research are as follows:(1)From 2000 to 2015,the transition zones' ecological security situation is sable and safe as a whole but the ecological security index tends to reduce.The high ecological security grade areas are mountainous area and the semi-mountainous area in the west and north where are far from cities and towns.However,the grade ofecological security in plain area is low because of the the activities of human beings are intense.The ecological security grades' of Dujiangyan,Dayi,and Qionglai are higher than the average.But the ecological security grades' of Pengzhou and Chongzhou are lower than the average.With the development of the economy,the extension of the main city zone and the development of the villages and towns which makes the ecological security index from high to low.(2)Spatial autocorrelation existed under four scales(?500*500??1000*1000??1500*1500??2000*2000)of regional ecological security are clearly effective in all four periods.The Morans' I decreased along with the increasing spatial autocorrelation.In other words,with the increase of the spatial autocorrelation and expansion of the study scale but the spatial autocorrelation of the study areas distance.The four periods' value of Moran's I reached the biggest value when the scale is500m*500m.(3)During the four periods from 2000 to 2015,study area with a similar ecological security tended to have an aggregated distribution which was enhanced as time increased.The cold-spot areas extend its area with the main city zone of the cities and some big towns as the core.Cold-spot areas are mainly distributed in plain areas in the east and south.The hot-spot are mainly distributed in mountainous areas in west and north where the effect of the human beings activities are small.(4)During the two periods of 2000 to 2007 and 2008 to 2015,the transition areas where the ecological security changed in a similar way showed obvious spatial cluster pattern,and differences was also enhanced considerably over time.From 2007 to2008,the ecological security changed still showed obvious spatial cluster pattern.The four kinds of the ecological security regions are changing on the space pattern.The main space structure of ecological security was high-high type and the second is the low-low type.The diffusion effect of both types of area gradually decreased over time. |
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