鄂尔多斯十大孔兑区植被生产力变化趋势对土地利用转移的响应

归一化植被指数(Normalized difference vegetation index,NDVI)是衡量区域植被生产力变化的一个重要指标,而土地利用/覆盖变化(Land use/cover change,LUCC)进程深刻影响了陆地生态系统空间分布格局及其生产力变化。因此本文结合趋势分析和转移矩阵法,从中分辨率成像光谱仪(Moderate-resolution Imaging Spectroradiometer,MODIS)NDVI年际变化角度分析鄂尔多斯北部典型农牧交错区(十大孔兑地区)2000-2015年植被生产力的变化趋势与LUCC的关系。结果表明:(1)在农牧交错区植被生产力总体呈增加趋势,其中显著增加和不显著增加区域面积占总面积的89.41%,分别为22.01%和67.4%;其后依次为不显著减少区域、无变化区域和显著减少区域,面积比例分别为4.59%、3.32%和2.68%。(2)在不显著增加和显著增加区,土地转换面积分别为235146.08 hm2和82761.76 hm2,草地转为农田、林地、水体、建设用地和未利用地尤其是草地转为农田导致对应区域植被生产力增加。

Response of change trend of vegetation productivity to land use conversion in Ten Tributaries Basin of Ordos

Land cover/use change (LUCC), which is a focus in global changing study, deeply influences the geographical distribution pattern and productivity of terrestrial ecological system. Normalized differential vegetation index (NDVI), as a key indicator of vegetation productivity, plays an important role in assessing regional vegetation productivity. We selected Ten Tributaries Basin (TTB), where the Yellow River has ten first-level tributaries, to analyze the relationship between the vegetation change trend and LUCC conversion based on the annual data of MODIS NDVI from 2000 to 2015 in the northern part of Ordos, China. Meanwhile, this study employed trend analysis and transfer matrix to analyze the relationships. The results showed that the productivity had an increasing trend totally due to the dominance of grasslands in farming-pastoral region, and areas of significant increase and unsignificant increase account for 22.01% and 67.4% of the total area, respectively. The areas of unsignificant decrease, unchange and significant decrease account for 4.59%, 3.32% and 2.68%, respectively. Land conversion areas in unsignificant increase and significant increase come to 235146.08 hm² and 82761.76 hm², respectively. The conversion of grassland to farmland, woodland, water body, construction land and unused land, especially the conversion of grassland to farmland, led to the increase of vegetation productivity in corresponding regions.