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Desert ecosystems possess an astonishing biodiversity and are rich in endangered species. This study investigated characteristics of species diversity and soil environmental factors in three major deserts of China's Alxa Plateau. The Alxa Desert included 183 plant species belonging to 109 genera and 35 families. The highest numbers of plant species belonged to the Compositae, Gramineae, and Chenopodiaceae families. The research area belongs to the semi-shrub and small semi-shrub deserts in temperate deserts. Species diversity was low, with the Shannon–Wiener index (H′) of shrub-herb = shrub > herb > tree. The Pielou evenness index (E) of shrub herb vegetation was the lowest, indicating more enriched species and fewer sparse species in the community, and that these types of vegetation had the characteristics of rich and obviously dominant species. Redundancy analysis (RDA) and correlations between the comprehensive plant community biodiversity index and soil factors indicated that soil-available phosphorus (NP), organic matter (SOM), and electrical conductivity (EC) had significant impacts on community species diversity. The herbaceous shrub community exhibited the highest H′, Simpson index (D), species richness index (S), soil moisture (SW), and soil nutrients. Planting Calligonum mongolicum, Ephedra membranacea, Artemisia annua, and Phragmites australis to form a typical desert shrub community for community diversity protection is recommended to effectively protect and restore desert ecosystems. [ABSTRACT FROM AUTHOR]

Mega-dunes in the lake group area of the Badain Jaran Sand Sea, China, are generally taller than dunes in the non-lake group area. This spatial distribution of dune heights may provide a new perspective on the controversy regarding the dunes' formation mechanism. In this study, we calculated the relative heights and slopes of individual dunes based on a digital elevation model, and we confirmed the height distribution of abnormally tall dunes in the lake group area of the sand sea. It was also found that slopes of more than 10° in the lake group area are more common than those in the non-lake group area. Based on meteorological observations, coupled with the measurement of water content in the sand layers, we propose a conceptual model demonstrating that moisture exchange between the lakes and soil via non-rainfall water will humidify dune slopes and form a more favorable accumulation environment for aeolian sand, thus increasing dune heights. Although long-term observations are yet to be carried out, the present study can be used as evidence for understanding the basis of dune formation in the lake group area and assessing groundwater utilization in deserts. [ABSTRACT FROM AUTHOR]