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Analysis of Service Value and Changing Characteristics of Ecological Land in Simao Basin in Recent 20 Years Based on Visualization of Remote Sensing

Ecological land has irreplaceable functions such as regulation of drought and flood, conservation of biodiversity, aesthetic education, and heritage preservation. It's helpful to grasp the response of ecological land to the process of urbanization and provide localized case for reference by identifying the changed characteristics of ecological land and analyzing its service value. Based on the five-phase Landsat remote sensing images from 1997 to 2017 as the data source, combined with the visualization technology of remote sensing, which is used for the dynamic analysis and thematic map expression of service value and changed characteristics of ecological land in Simao basin. The results show that:(1) the classification method combined with support vector machine (SVM) after the decomposition of mixed pixels is more suitable for the identification of ecological land information in the study area, and the accuracy can reach 85.53%. (2)The overall number of dynamical change of ecological land in the study area shows a downward and convergent trend, from 3164.13hm2 in 1997 to 2745.63hm2 in 2017. The woodland area as a whole shows a decreasing trend of varying degrees, but there is a small increase in between 2012 and 2017; and the garden land area shows the “inverted V -shaped” trend in 2002 when is the main boundary line, while the increase and decrease of farmland area are not fixed and alternate, showing irregular changes. (3)The change of the total service value of ecological land in the study area is declining, which is from 12.7217 × 107 yuan in 1997 to 9.6565 × 107 yuan in 2017, the ecological service value decrease by 3.0652 × 107 yuan during the period, and the reduction of average annual is 0.1533 × 107 yuan/a. The changing characteristics of ecological land in Simao basin within 20 years reflects the process of urban expansion, which aggravates the fragmentation of the ecological landscape pattern to a certain extent, interferes with the ecological self-efficacy of local ethnic groups, and damages the stability and diversity of the ecosystem in study area.