河西走廊草地荒漠化动态及驱动因素

Dynamic characteristics and driving factors of grassland desertification in Hexi Corridor

草地荒漠化是河西走廊面临的主要生态问题。探究河西走廊草地荒漠化的现状与变化,是维持地区生态安全、确保经济社会健康稳定发展的关键。本研究以2009、2014、2019年全国荒漠化监测数据为基础,结合同时期的气象和年鉴数据,利用趋势分析、灰色关联及结构方程模型等方法,分析了河西走廊草地荒漠化的动态变化规律,在此基础上,量化了驱动草地荒漠化的因素。结果表明:(1)河西走廊草地荒漠化威胁持续存在,2019年,荒漠化草地面积为371.93万hm^(2),占河西走廊草地总面积的43.7%,荒漠化程度以中度为主,占比为65.58%。(2)2009—2019年,荒漠化草地面积减少134.68万hm^(2),草地荒漠化得到有效遏制。根据草地荒漠化程度综合性评价指数,除金昌市外,酒泉市、嘉峪关市、张掖市和武威市草地荒漠化呈逆转趋势。(3)驱动草地荒漠化动态变化的各类因素中,年降水量增加有助于荒漠化逆转,年均气温、农作物播种面积、大牲畜存栏数、常住人口数与草地荒漠化呈正相关,其中常住人口数通过影响农作物播种面积间接导致草地荒漠化加剧。

Grassland desertification is the main ecological problem in Hexi Corridor.Therefore,exploring the status and changes of grassland desertification in the Hexi Corridor is the key to maintain regional ecological security and ensure healthy and stable economic and social development.Based on the three national desertification monitoring data in 2009,2014 and 2019,and combined with the meteorological and yearbook data of the same period,our study analyzed the rule of dynamic changes of grassland desertification in the Hexi Corridor by applying trend analysis,grey correlation and structural equation modeling,and on this basis,the factors driving grassland desertification were quantified.The results show that:(1)The threat of grassland desertification persists in the Hexi Corridor region.In 2019,the desertified grassland area was 3.7193 million hm^(2),accounting for 43.7%of the total grassland area in the Hexi Corridor,and the degree of desertification was mainly moderate,accounting for 65.58%of the total desertification grassland.(2)From 2009 to 2019,the area of desertified grassland decreased by 1.3468 million hm^(2),and the grassland desertification tended to be reversed.The comprehensive evaluation index of grassland desertification degree showed that,except for Jinchang City,the grassland desertification in Jiuquan City,Jiayuguan City,Zhangye City and Wuwei City showed reversing trend.(3)Among the driving factors that cause the dynamic changes of grassland desertification,the increase of precipitation is helpful for the reversal of desertification.Among them,temperature,crop sown area,number of large livestock,and permanent population are positively correlated with grassland desertification,and the permanent population indirectly promote the exacerbation of grassland desertification by affecting the sown area of crops.