川西北高寒草原退化沙化成因分析——以红原县为例

Analysis on the causes of degeneration and sandification of alpine grassland in northwest part of Sichuan Province——Taking Hongyuan County as the example

川西北高寒草原是全国5大牧区之一,同时作为长江黄河两大水系的发源地,也具有着十分重要的生态作用。但草原退化沙化现象严重,以川西北的红原县为例,采用3S技术结合实地调查和室内分析的方法,研究了在高寒湿润条件下草原的退化、沙化的主要成因。结果表明:草原的退化、沙化是自然成因和人为成因共同作用的结果。自然成因包括地形地貌和水文母质因素、气候因素;人为成因包括过渡放牧,滥垦乱挖和疏干沼泽等因素。其中,自然成因是造成研究区沙化的基础性因素,人为不合理的经济活动,在一定程度上引发和大大加速了草原的沙化;而人为因素是造成由沼泽草甸-草原草甸-草原草地-退化草地退化的主要成因,其中以过度放牧最为普遍和严重。

The alpine grassland area located in the northwestern Sichuan Province was one of the five main pasturing areas in China,and as the headstream of both Yellow River and Yangtze River,it was a very important ecosystem. However,the degradation and sandification situation in this area is very serious in recent years. The main reasons of the grassland degradation and sandification was studied by taking Hongyuan County as the example through field investigation and 3S technologies. The results showed that the degradation and sandification of the grassland were caused by the effects of natural factors and man-made factors. The natural causes were landform,parent materials and weather. The man-made causes were over grazing and estrepement. The natural factors were the basic causes of sandification in Hongyuan. The unreasonable economic activities caused and greatly accelerated the grassland sandification at a certain extent. However,the man-made factor is the most important cause to the degradation succession of bog meadow-grassland meadow-grassland-degradation grassland, and over grazing was the most common and serious cause.