Analysing the forcing mechanisms for net primary productivity changes in the Heihe River Basin, north‐west China
Analysing the forcing mechanisms for net primary productivity changes in the Heihe River Basin, north‐west China
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DOI：
10.1080/01431160802438530
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发表时间：
2009-02
影响因子：
3.4
通讯作者：
Le Lu;X. Li;Frank Veroustraete;E. Kang;J. Wang
中科院分区：
文献类型：
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作者：
Le Lu;X. Li;Frank Veroustraete;E. Kang;J. Wang
在过去的几十年里，中国西北地区的大多数内陆河流域都经历了生态系统退化甚至荒漠化。以黑河流域为例，利用Monteith型参数NPP模型C-Fix估算了流域2002年和1998年的净初级生产力，并分析了其差异。所使用的数据包括从1公里SPOT/VEGETATION传感器和其他环境记录得出的归一化差异植被指数。通过获取流域NPP变化和土地利用变化的时空格局，从气候变化和人类活动的角度，我们确定了其驱动因素。我们认为，降水量的下降，在五年的NPP减少的流域的原因之一。其他因素，如上游的不合理开垦和中游灌溉农田的集约化发展，起着更重要的作用。它们加强了整个流域人工和自然生态系统之间的水竞争。同时还发现，人类活动在短时间内会引起山地NPP的显著变化。生态系统保护工程研究表明，祁连山东部地区由于开垦和过度放牧，净第一性生产力呈下降趋势，而西部地区则呈上升趋势。
Most of the inland river basins in north‐west China have experienced ecosystem degradation and even desertification in the last few decades. As a case study, we estimated the net primary productivity (NPP) of the Heihe river basin and analysed its difference between 2002 and 1998 by using the C‐Fix, a Monteith type parametric NPP model. The data used include the normalized difference vegetation index (NDVI) derived from the 1‐km SPOT/VEGETATION sensor and other environmental records. By obtaining the spatiotemporal patterns of NPP change as well as land use changes from higher resolution imagery in the basin, we identified its forcing factors in terms of climate change and human activities. We suggest that a decline in rainfall over the five years was one reason for NPP decrease in the basin. Other factors, such as irrational reclamation upstream and intensive development of irrigated farmland in the midstream play more important roles. They reinforce water competition between artificial and natural ecosystems over the whole basin. It is also found that human activities can produce very different NPP changes in a short time in mountainous regions. The NPP decreased in the east Qilian Mountains due to farmland reclamation and overgrazing but increased in the west, according to the ecosystem preserve project.