川北若尔盖高原盆地沙漠化、岩漠化遥感动态监测研究

Remote-sensing dynamic monitoring of sand-and rock-desertification of the Zoigê Plateau basin, northern Sichuan, China

若尔盖高原盆地是全国五大牧区之一,曾是青藏高原东北缘最好的草场。若尔盖高原盆地生态环境脆弱,生态平衡极易被打破。一旦失去平衡,生态环境将呈现由沼泽→草原→荒漠草原→荒漠逐级退化的发展趋势。20世纪80年代中期以来,若尔盖高原盆地逐渐沙漠化、岩漠化,部分地段甚至出现沙(岩)进人退、沙(岩)进路移的景象。遥感动态调查证实,该地区2000年沙漠化、岩漠化区面积已达43911.15hm2,比1986年扩大了6280.44hm2。沙漠化主要分布在山丘的北坡和垭口,岩漠化分布在山丘的南坡。沙漠化、岩漠化主要受北西向季风、地貌条件、松散沉积物、古沙丘等自然因素和过度放牧等人为因素控制。

The Zoigê Plateau basin, which used to be the best pasture on the southeastern margin of the Qinghai-Tibet Plateau, is one of the five largest pastures of China. The ecological environment of the Zoigê Plateau basin is fragile and the ecological balance is easy to destroy. Once the balance is destroyed, the environment will tend to degrade gradually from the swamp→grassland→desert grassland→desert. Since the middle 1980s, the plateau basin has been sand- and rock-desertified progressively and in some places there even appears the following sight： with the advance of the sand （rock）, inhabitants have to give in and withdraw and roads have to change their original routes. Remote sensing dynamic monitoring confirms that by 2000 the area of the sand- and rock-desertified districts had reached 43911.15 hm^2, an increase of 6280.44 hm^2 over 1986. The hill sand desertification is mostly distributed on the north slopes of the hills and mountain mouths, while the hill rock desertification is distributed on the south slope. The former is mainly controlled by monsoons from the northwest, geo- morphological conditions, loose sediments and ancient sand dunes; whereas the latter is mainly influenced by the factors such as air temperature rise, solar radiation and gale. Human factors such as overgrazing are also an important cause.