2000年以来西秦岭地区植被覆盖变化特征——以陇南市为例

Study on Spatiotemporal Variations of Vegetation Cover in the Western Qinling Mountain Areas During the Period from 2000 to 2010——A Case of Longnan of Gansu,China

利用NDVI数据,以陇南市为案例区,研究了2000年以来西秦岭地区植被覆盖度变化的时空特征。采集2000—2010年6—10月NDVI数据,利用像元二分法设计了植被覆盖度(Vc)的计算方法,结果显示,2000—2010年陇南市植被覆盖度变化呈基本稳定态势,与同期温度和降雨的变化显著相关。利用一元线性回归和标准差方法,分析了Vc的时空变化特征,结果显示,土地面积将近90%的区域表现为稳定趋势,Vc的年际波动较小,空间分布与林地的分布区域基本吻合;将近1/10的区域表现为上升趋势,Vc的年际波动较大,主要分布在徽成盆地、西礼盆地、白龙江河谷阳面山坡等区域,与耕地、草地分布区域基本吻合,表明退耕还林工程对植被覆盖度增加的贡献显著。论文为20世纪末以来西秦岭地区生态建设的成效提供了证据,也为当地深化生态环境建设和可持续发展提供了借鉴。

As the main topic of terrestrial ecosystem study, vegetation cover change gained extensive attention in the process of global climate change and sustainable development recently. Based on M（）DIS NDVI data from June to October during the period from 2000 to 2010, taking Longnan City as a case area, we developed the calculation method of vegetation cover （V,） by using Pixel Dichotomy model and analyzed the spatiotem- poral variations of vegetation cover in the western Qinling Mountain areas by using simple linear regression and standard deviation method. The results showed that vegetation cover remained stable and significantly correlated with temperature and precipitation during the decade. The vegetation cover of 90% of study area showed the stability with small annual variation and also was consistent with the spatial distribution of forest land while the vegetation cover in other 10% of study areas showed the growing tendency with significant variations and also was consistent with the spatial distribution of farmland and grassland, especially in Huicheng Basin, Xili Basin and adret slope of Bailong River Valley, which indicates that the Grain for Green project has the great contribution to vegetation cover increase. This study proved the effect of ecological construction in the western Qinling Mountain areas since late last century. All the findings can also provide references for local ecological environment construction and sustainable development.