呈贡区近30年植被覆盖度时空变化特征与土地利用驱动

Temporal and Spatial Variation Characteristics of Vegetation Coverage and Land Use Driving in Chenggong District in Recent 30 Years

以1990—2018年Landsat数据为基础,辅以像元二分法、小波分析、趋势分析、面向对象最近邻分类法等,探究呈贡区植被覆盖时空分布、趋势变化、空间波动特征及与土地利用关系。时间上,呈贡区FC呈缓慢增长态势,主要存在14,7 a共2个变化周期控制着FC在整个时间域内的变化特征。空间上,呈贡区整体呈现外围FC较高,并向中部区域递减的特征。区域高植被覆盖区域占71.92%,植被整体较好。植被改善面积占39.02%,退化面积占25.52%,改善区域主要位于呈贡东部山区。中部约占总面积2/3的区域为中高态势波动变化。FC较高和改善地区主要位于现呈贡区东部林地;高波动变化为中部耕地、裸地转为建设用地和林地区域。转换为林地主要由裸地、耕地和建设用地构成,其中裸地转换比例达25.94%;高达31.14%的建设用地及26.93%的耕地转换为裸地。

Based on the Landsat data from 1990 to 2018,pixel dichotomy,wavelet analysis,trend analysis,and object-oriented nearest neighbor classification,the temporal and spatial distribution,trend variation,spatial fluctuation characteristics and land use of vegetation cover in Chenggong District were explored.With respect to the time scale,the FC in Chenggong District showed a slow growth trend,and there were mainly two periods of change in 14 years and 7 years to control the variation characteristics of FC in the whole time domain.With respect to spatial scale,the Chenggong District as a whole presented a feature that the peripheral FC was higher and decreased toward the central region.The area with high vegetation coverage accounted for 71.92%,and the overall vegetation was better.The area of vegetation improvement accounted for 39.02%,and the degraded area accounted for 25.52%.The improvement area was mainly located in the eastern mountainous area of Chenggong District.The central part of the area of about 2/3 of the total area was fluctuating in the middle and high.The higher and improved areas of FC were mainly located in the eastern forest land of the present Chenggong District;the high fluctuation change was observed in the central cultivated land,the bare land converted into the construction land and the forest land area.The bare land,cultivated land and construction land were mainly converted into forest land,of which the proportion of converted bare land was 25.94%;up to 31.14%of construction land and 26.93%of cultivated land were converted into bare land.