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石羊河流域中下游位于干旱荒漠区,河岸带植被破坏、生物多样性下降,区域生态系统和生态过程受到严重影响。运用空间变化代替时间过程的方法,对石羊河流域中下游不同河段河岸带植被与土壤特征及两者相关性进行了研究。结果表明:石羊河中下游从常流水区、季节性流水区到常年断流区,随着河床的常年和季节性断流,植被与土壤逐渐退化。植被盖度、生物量和丰富度指数呈下降趋势,多样性指数呈上升趋势。不同河段的土壤理化特征差异性显著,河流断流对土壤产生了直接或间接影响;但是从季节性流水区到常年断流区表征土壤肥力和水分的指标均呈增大趋势,常年断流区土壤已经逐渐改善。植被盖度和生物量分别与土壤含水量、全氮,电导率有线性关系。修复该区的退化生态系统需要保证适宜的土壤含水量。
The middle and lower reaches of Shiyang River Basin is located in the arid desert area. The riparian vegetation is destroyed, the biodiversity is declining, and the regional ecosystems and ecological processes are seriously affected. By using the method of spatial change instead of time process, the characteristics of vegetation and soil in the riparian zone of the middle and lower reaches of Shiyang River Basin and the correlation between them were studied. The results show that the middle and lower reaches of Shiyang River flow from the normal flow area and the seasonal flow area to the normal cutoff area. The vegetation and soil gradually degenerate with the annual and seasonal cutoff of the riverbed. Vegetation coverage, biomass and abundance index showed a downward trend and diversity index showed an upward trend. The differences of soil physical and chemical characteristics in different reaches were significant. The river runoff had a direct or indirect impact on the soil. However, the indices for characterizing soil fertility and water from the seasonal flow area to the perennial drying area showed an increasing trend, The area of soil has been gradually improved. Vegetation coverage and biomass were linear with soil water content, total nitrogen and conductivity, respectively. Rehabilitation of degraded ecosystems in the area requires adequate soil moisture content.