Ili River Valley is the main agricultural and animal husbandry base. Meanwhile, it is also one of the most serious soil erosion areas in Xinjiang, China. Vegetation is the most important component of terrestrial ecosystems and a key indicator for assessing the interaction between climate and the terrestrial ecosystems. The study of vegetation cover change is of great significance in preventing soil erosion and improving ecological environment. Based on the EOS/MODIS data from 2000 to 2015, the degree of vegetation coverage and its spatial change characteristics during 2000 to 2015 was analyzed. Trend analysis method was used to analyze vegetation cover change during 2000 to 2015. The Hurst index was used to predict the future change of vegetation cover. Coefficient of variation method was used to analyze the dispersion degree and fluctuation of vegetation spatial distribution. The results showed as follow: (1) Spatial distribution pattern of high vegetation coverage in Ili River Valley was distributed in the north, south, and east, while the region of low vegetation coverage is distributed in the west and middle. The ratio of vegetation area in poor, medium, and good condition accounted for 12.75%, 16.11%, and 71.14% of the total area, respectively. (2) Affected by natural factors such as temperature rise, precipitation decrease, and human factors such as overgrazing, the average NDVI in Ili River Valley fluctuated between 0.58 and 0.68, and the vegetation cover has a decreasing trend of fluctuation with the rate of 6.25 %·(10 a)- 1. (3) Generally speaking, there was a relatively low vegetation change trend in Ili River Valley. Regions with low fluctuation degree accounted for 73.16% , which were mainly distributed in the mountainous area of Ili River Valley. The vegetation types were mountain meadow, alpine meadow, and primitive forest. Regions with high fluctuation degree accounted for 26.84%, which were mainly distributed in the altitudes (0-1 500 m) of Tekes River, Künes River, Ili River, and the sunny slope of mountain body. (4) The vegetation coverage of Ili River Valley will decrease in future. The area of vegetation decreased accounting for 76.90% , which was mainly distributed in high altitude areas of Huocheng County, Yining County, Gongliu County, Xinyuan County, Tekes County, and Zhaosu County. The area of vegetation increased and accounted for 23.10%, which was mainly distributed in the low and gentle slopes of Qapqal County, Yining County, and Yining City. (5) The change trend of vegetation cover in Ili River Valley was more complex. The areas of continuous degradation and improvement of vegetation cover were obviously distributed in spatial distribution. The area of continuous degradation of vegetation accounted for 57.55%, which was mainly distributed in the higher altitude areas of the north Tianshan Mountains, the middle Tianshan Mountains, and the south Tianshan Mountains. The area of continuous improvement of vegetation accounted for 13.51% , which was mainly distributed in the newly reclaimed areas of the Ili River valley. Results of this study would provide a scientific support for better understanding the status of ecological environment and the vegetation change trend in Ili River Valley and also for formulating the corresponding ecological protection countermeasures in future.
[1] LI Z, CHEN Y N, LI W H, et al. Potential impacts of climate change on vegetation dynamics in Central Asia[J]. Journal of Geo⁃ 6208. [LIU Yang, LI Chengzhi, LIU Zhihui, et al. Assessment of spatio-temporal variations in vegetation cover in Xinjiang from 1982 to 2013 based on GIMMS- NDVI[J]. Acta Ecologica Sinica, 2016, 36(19): 6198－6208. ] [10] 赵安周, 刘宪锋, 朱秀芳, 等. 2000—2014 年黄土高原植被覆盖 时空变化特征及其归因[J]. 中国环境科学, 2016, 36(5): 1568－ 1578. [ZHAO Anzhou, LIU Xianfeng, ZHU Xiufang, et al. Spatio⁃ temporal analyses and associated driving forces of vegetation cov⁃ erage change in the Loess Plateau[J]. China Environmental Sci⁃ ence, 2016, 36(5): 1568－1578. ] [11] TUCKER C J, SLAYBACK D A , PINZON J E, et al. Higher north⁃ ern latitude normalized difference vegetation index and growing season trends from 1982 to 1999[J]. International Journal of Bio⁃ meteorology, 2001, 45(4): 184－190. [12] 邓兴耀, 姚俊强, 刘志辉. 基于 GIMMS NDVI 的中亚干旱区植 被覆盖时空变化 [J]. 干旱区研究, 2017, 34(1): 10－19. [DENG Xingyao, YAO Junqiang, LIU Zhihui. Spatiotemporal dynamic change of vegetation coverage in arid regions in Central Asia based on GIMMS NDVI[J]. Arid Zone Research, 2017, 34(1): 10－ 19. ] [13] 刘宪锋, 任志远. 西北地区植被覆盖变化及其与气候因子的关 系[J]. 中国农业科学, 2012, 45(10): 1954－1963. [LIU Xianfeng, REN Zhiyuan. Vegetation coverage change and its relationship with climate factors in northwest China[J]. Scientia Agricultura Si⁃ nica, 2012, 45(10): 1954－1963. ] [14] 闫俊杰, 乔木, 周宏飞, 等. 基于 MODIS／NDVI 的新疆伊犁河 谷植被变化[J]. 干旱区地理, 2013, 36(3): 512－519. [YAN Jun⁃ jie, QIAO Mu, ZHOU Hongfei, et al. Vegetation dynamics in Ili River Valley of Xinjiang based on MODIS／NDVI[J]. Arid Land Geography, 2013, 36(3): 512－519. ] [15] 王倩, 杨太保, 杨雪梅. 伊犁河流域归一化植被指数的时空变化 及 其 对 气 候 的 季 节 响 应 [J]. 兰 州 大 学 学 报（自 然 科 学 版）, 2016, 52(4): 466－474. [WANG Qian, YANG Taibao, YANG Xue⁃ mei. The spatio-temporal changes of normalized difference vegeta⁃ tion index and its response to seasonal climate in Ili River Basin [J]. Journal of Lanzhou University: Natural Sciences, 2016, 52(4): 466－474. ] [16] 王洪亮, 冯爱萍, 高彦华, 等. 伊犁河流域最大植被覆盖度的时 空 动 态 变 化 [J]. 环 境 科 学 与 技 术, 2018, 41(6): 161 － 167. [WANG Hongliang, FENG Aiping, GAO Yanhua, et al. Temporal- spatial dynamic change on maximum vegetation coverage degree of Ili River Basin[J]. Environmental Science & Technology, 2018, 41(6): 161－167. ] [17] SUN G J, LI W H, ZHU C G, et al. Spatial variability of soil car⁃ bon to nitrogen ratio and its driving factors in Ili River Valley, Xin⁃ jiang, northwest China[J]. Chinese Geographical Science, 27(4): 529－538. [18] 张建亮, 刘方正, 崔国发, 等. 长白山国家级自然保护区植被时 空变化及其驱动因子[J]. 生态学报, 2016, 36(12): 3525－3536. [ ZHANG Jianliang, LIU Fangzheng, CUI Guofa, et al. Spatio-tem⁃ poral variation of vegetation and analysis of its driving factors in Changbai Mountain National Nature Reserve[J]. Acta Ecologica Si⁃ nica, 2016, 36(12): 3525－3536. ] [19] SUN J, CHENG G W, LI W P, et al. On the variation of NDVI with the principal climatic elements in the Tibetan Plateau[J]. Remote Sensing, 2013, 5(4): 1894－1911. [20] CAO L, XU J H, CHEN Y N, et al. Understanding the dynamic coupling between vegetation cover and climatic factors in a semiar⁃ id region: A case study of Inner Mongolia, China[J]. Ecohydrology, 2013, 6(6): 917-926. [21] 李双双, 延军平, 万佳. 近 10 年陕甘宁黄土高原区植被覆盖时 空变化特征[J]. 地理学报, 2012, 67(7): 960－970. [ LI Shuangsh⁃ uang, YAN Junping, WAN Jia. The spatial- temporal changes of vegetation restoration on Loess Plateau in Shanxi- Gansu- Ningxia region[J]. Acta Geographica Sinica, 2012, 67(7): 960-970. ] [22] 毛德华, 王宗明, 罗玲, 等. 基于 MODIS 和 AVHRR 数据源的东 北地区植被 NDVI 变化及其与气温和降水间的相关分析[J]. 遥 感技术与应用, 2012, 27(1): 77－85. [MAO Dehua, WANG Zong⁃ ming, LUO Ling, et al. Correlation analysis between NDVI and cli⁃ mate in northeast China based on AVHRR and GIMMS data sourc⁃ es[J]. Remote Sensing Technology & Application, 2012, 27(1): 77－85. ] [23] 张宝庆, 吴普特, 赵西宁. 近 30 a 黄土高原植被覆盖时空演变监 测与分析[J]. 农业工程学报, 2011, 27(4): 287－293. [ZHANG Baoqing, WU Pute, ZHAO Xining. Detecting and analysis of spa⁃ tial and temporal variation of vegetation cover in the Loess Plateau during 1982—2009[J]. Transactions of the Chinese Society of Ag⁃ ricultural Engineering, 2011, 27(4): 287－293. ] [24] 张宏斌, 唐华俊, 杨桂霞, 等. 2000—2008 年内蒙古草原 MODIS NDVI 时空特征变化[J]. 农业工程学报, 2009, 25(9): 168－175. [ZHANG Hongbin, TANG Huajun, YANG Guixia, et al. Changes of spatial-temporal characteristics based on MODIS NDVI data in Inner Mongolia grassland from 2000 to 2008[J]. Transactions of the Chinese Society of Agricultural Engineering, 2009, 25(9): 168－175. ] [25] 刘芳, 张红旗, 董光龙, 等. 伊犁河谷草地植被 NDVI 变化及其 降水敏感性特征[J]. 资源科学, 2014, 36(8): 1724－1731. [ LIU Fang, ZHANG Hongqi, DONG Guanglong, et al. Vegetation dy⁃ namics and precipitation sensitivity in Yili Valley grassland[J]. Re⁃ sources Science, 2014, 36(8): 1724－1731. ] [26] 孙国军, 李卫红, 朱成刚, 等. 新疆伊犁河谷表层土壤容重的空 间 变 异 性 分 析 [J]. 资 源 科 学, 2016, 38(7): 1222 － 1228. [SUN Guojun, LI Weihong, ZHU Chenggang, et al. Spatial variation anal⁃ ysis of topsoil bulk density in the Yili Valley, Xinjiang[J]. Resourc⁃ es Science, 2016, 38(7): 1222－1228. ] [27] 汪洋, 靳瑰丽, 李卫红, 等. 伊犁河谷土地利用变化对生态服务 价 值 的 影 响 [J]. 环 境 与 可 持 续 发 展, 2017, 42(2): 151 － 155. [WANG Yang, JIN Guili, LI Weihong, et al. The spatial coupling of land use／cover change and its environmental effects on Ili Val⁃ ley[J]. Environment and Sustainable Development, 2017, 42(2): 151－155. ] [28] 陈秀妍, 付碧宏, 时丕龙, 等. 2000—2016 年中亚天山植被变化 及 气 候 分 异 研 究 [J]. 干 旱 区 地 理, 2019, 42(1): 162 － 171. [CHEN Xiuyan, FU Bihong, SHI Pilong, et al. Vegetation dynam⁃ ics in response to climate change in Tianshan, Central Asia from 2000 to 2016[J]. Arid Land Geography, 2019, 42(1): 162－171. ] [29] 靳建辉, 李志忠, 马鹏, 等. 新疆伊犁河谷新垦绿洲土壤主要养 分含量特征[J]. 亚热带资源与环境学报, 2011, 6(1): 39－44. [JIN Jianhui, LI Zhizhong, MA Peng, et al. Organic matter, total ni⁃ trogen and total phosphorus features of oasissoil ina newly rec⁃ lamatedarea of Yili Valley, Xinjiang Province[J]. Journal of Sub⁃ tropical Resources and Environment, 2011, 6(1): 39－44. ]
