2000—2016年甘肃祁连山自然保护区土地覆被时空变化分析

Temporal and Spatial Variation of Land Cover in Gansu Qilian Mountains Nature Reserve from 2000 to 2016

利用102景Landsat TM/ETM+/OLI遥感影像和美国航天局NASA数据共享网数据作为甘肃祁连山自然保护区的基础研究数据,对祁连山自然保护区土地覆被、植被覆盖指数(EVI)的时空变化进行分析。结果表明,整个保护区生态系统组成以草地为主,占总面积的52.9%;其次是荒漠、森林、农田、冰川积雪、湿地。森林主要以落叶阔叶灌丛为主,主要分布在实验区,面积占该类林地总面积的44.4%;温性草原主要分布在实验区,占该类草地面积的55.0%,分布在外围保护地带的占36.0%,分布在核心区的最少。近16年来主要生态系统整体处于稳定状态,2000—2005年自然保护区整体变化趋势是森林和草地生态系统及冰川积雪面积减少,农田、湿地、荒漠和人工生态系统面积增加; 2005—2010年,森林、农田、湿地、荒漠生态系统和冰川积雪面积净减少,草地和人工生态系统面积净增加;2010—2016年,草地、农田和荒漠生态系统面积净减少,森林、湿地、人工生态系统和冰川积雪面积是净增加。祁连山自然保护区年EVI总体上呈现片状分布特征,且存在一定的空间分布差异。EVI高值即植被覆盖指数高区域主要分布在自然保护区的东南区域,西北区域EVI值普遍较低,年植被覆盖度变化与生长季植被覆盖度变化基本一致。

Using 102 Landsat TM/ETM＋/OLI remote sensing images and NASA’s NASA data sharing network data as the basic research data of Gansu Qilian Mountains nature reserve,the temporal and spatial changes of land cover and EVI in the Qilian Mountains nature reserve are analyzed.The results showed that the ecological system of the whole protected area was mainly composed of grassland,accounting for 52.9% of the total area,followed by desert,forest,farmland,Glacial Snow and wetland.The main forest was deciduous broad-leaved shrubs,mainly distributed in the experimentation area.The area accounts for 44.4% of the total area of this kind of woodland.The temperature grassland mainly distributes in the experimentation area,accounting for 55.0% of the area of this kind of grassland,36.0% in the peripheral protection zone,and the least in the core area.In the last 16 years,the main ecosystems were in a stable state.During 2000-2005,the overall change trend of natural reserves was the decrease in the area of forest and grassland ecosystems and Glacial Snow,and the increase in the area of farmland,wetlands,deserts and artificial ecosystems.During 2005-2010,forests,agricultural fields,wetlands,desert ecosystems and glaciers;net snow cover decreased and grassland and artificial ecosystem area increased.During 2010-2016,the area of grassland,farmland and desert ecosystem decreased,while forest,wetland,artificial ecosystem and glacier snow area increased.The annual EVI of Qilian Mountains nature reserve showed a plate-like distribution in general,and there was a certain spatial distribution difference.The high value of EVI,that was,the high area of vegetation cover index was mainly distributed in the southeast region of the natural reserve,and the EVI value in the northwest region was generally low.The change of vegetation coverage in the year was basically the same as the vegetation coverage in the growing season.