中文摘要：

基于对黑河流域中下游荒漠区植被和土壤生境的调查分析，以土壤水分在各调查样地中的差异来反映研究区的生态水文特征，采用种的丰富度和多度来代表荒漠植物多样性研究了荒漠植物，包括隐花植物多样性分布对土壤水分变化的响应。土壤水分变化不仅直接影响着荒漠植物的多样性，而通过影响其它生境因子又间接地影响着多样性的维持。因此，如何维持中下游相对稳定的土壤水分来源是该区荒漠植物多样性保育今后所要面临的挑战。

英文摘要：

Based on the investigation for vegetation and soil habitat in the desert areas in the middle-lower reaches of the Heihe River, the relationship between the distribution of vascular plant and cryptogam species diversity and the variation of soil water contents has been studied. Species diversity was presented by species richness and species abundance. Soil water contents in the different investigative plots were used to present the characteristics of eco-hydrological processes in the study areas. Our results show that the effects of the shallow soil water on the diversity of herbaceous species, in particular, on species diversity of annual plants and ephemeral plants are much more significant than that on woody species. The woody species diversity is mainly depends on the deeper soil water contents. Cryptogamic diversity is closely associated with the soil shallow water content. The higher soil water contents are beneficial to the development and colonization of cryptogamic diversity, dominated by mosses and lichen. However, the lower soil water contents are favorable for developing cryptogamic diversity characterized by cyanobacteria and desert algae. The maintaining of cryptogamic diversity improved the habitat for development of species diversity of vascular plants in arid regions. In addition, the distribution of plant species is also regulated by biological traits of these plants, such as psammophytic and halophytic species. The effects of decreasing of soil water on species abundance are more obvious than that on species richness. In general, soil water contents of plots not only directly influence plant species diversity, but indirectly act on it through re-allocation of soil sources availability by soil water. Therefore, it will be a great challenge for biodiversity conservation how to maintain a relatively stable soil water in the middle-lower reaches of the Heihe River.