基于MODIS数据的锡林郭勒草原植被覆盖变化及驱动因子分析

防治荒漠化管理往往需要掌握人类因素对植被生长动态影响的关键数据,气候变化背景下的干旱半干旱地区草原植被覆盖多属于缓慢量变,这种变化很难通过土地利用/覆盖类型的转换来分析.旨在掌握2001—2014年内蒙古锡林郭勒草原植被覆盖变化时空特征,定量掌握关键区域气候因子与植被的动态关联关系,进而分离和评估气候和人类因素对区域植被覆盖变化的贡献.结果表明:研究区植被覆盖2001—2014年总体呈增加趋势,年内最大的归一化植被指数(normalized difference vegetation index,NDVI)每年增幅为0.001 8;气温和降水对锡林郭勒草原植被变化均有显著作用,两者共同驱动的NDVI预测模型决定系数(R2=0.65)大于气温(R2=0.46)或降水(R2=0.54)单要素驱动的结果;气候和人类因素对区域植被覆盖增长总体均呈现积极的作用,人类因素特别是生态治理保护措施对草原植被覆盖的贡献远大于气候因素变化.耦合遥感数据的植被变化驱动力分析方法,有助于提高干旱半干旱地区人地相互作用的定量评估能力,为防治荒漠化工作提供重要科学数据支撑.

Driving Factors of Vegetation Changes in Xilingol Grassland Based on MODIS Data

Assessment of vegetation change and its causes in arid and semiarid regions are important for ecosystem protection project management. However, slow changes of vegetation coverage in arid and semiarid regions are difficult to explain through land use/cover type changes. Aimed to analyze the sensitivity of climate driving factors on vegetation changes, the human-induced and climate-driven vegetation changes in the Xilingol Grassland, Inner Mongolia from 2001 to 2014 were distinguished. Results show that vegetation coverage in the study area from 2001 to 2014 has an increasing trend, and the annual maximum normalized difference vegetation index (NDVI) is 0. 0018. The decision coefficient ( R2 ) of the vegetation index prediction model constructed by temperature and precipitation factors is 0. 65, better than the results only using temperature factor (R2 =0. 46) or precipitation factor (R2 =0. 54 ) . The contribution of human factors to the increase in vegetation cover is much greater than that of climate factors. The RESTREND method is a useful tool to improve the assessment of human-induced vegetation changes in arid and semiarid regions, and can provide scientific data support for the prevention and control of desertification work.