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Journal of Desert Research ›› 2026, Vol. 46 ›› Issue (1): 209-218.DOI: 10.7522/j.issn.1000-694X.2025.00169

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Vegetation distribution characteristics and influencing factors along a precipitation gradient in the Qaidam Basin

Wenrong Kang1,2(), Wenzhi Zhao1(), Yongyong Zhang1, Denke Ma1, Yuanyuan Ma1,2, Yifan Yue3, Guoying Zhou4   

  1. 1.Linze Inland River Basin Research Station,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
    2.University of Chinese Academy of Sciences,Beijing 100049,China
    3.Ningxia University,Yinchuan 750021,China
    4.Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810008,China
  • Received:2025-10-30 Revised:2025-12-22 Online:2026-01-20 Published:2026-03-09
  • Contact: Wenzhi Zhao

Abstract:

Precipitation is a key factor governing the spatial differentiation of vegetation and plant community dynamics in arid regions. This study was conducted in the Qaidam Basin, where typical desert sites along three mean annual precipitation gradients (200-300 mm, 100-200 mm, and 50-100 mm) were selected to investigate plant community composition, spatial patterns, and soil physicochemical properties, and to explore their relationships with precipitation. Vegetation composition and spatial structure were quantified through field quadrat surveys combined with UAV-based imagery, and their associations with environmental factors were examined using diversity indices, landscape metrics, Mantel tests, and correlation analyses. The results showed that, with decreasing precipitation, the proportion of herbaceous species declined markedly, and plant communities in the 50-100 mm precipitation zone became dominated by a single shrub life form. The Shannon-Wiener diversity index was significantly higher in the 200-300 mm zone (1.14±0.32) than in the 100-200 mm (0.93±0.74) and 50-100 mm (0.36±0.40) zones, whereas Evenness and Margalef richness indices did not differ significantly among precipitation gradients (P>0.05). Vegetation cover decreased significantly with declining precipitation, with mean values of 11.15%, 6.37%, and 1.81% for the three gradients, respectively, accompanied by a shift in spatial pattern from relatively continuous to sparse and fragmented. Soil nutrient levels were generally low and showed no significant differences among precipitation zones. Total nitrogen in the 0-20 cm soil layer was highest in the 200-300 mm zone (0.05 g·kg⁻¹), while total phosphorus and total potassium reached their highest values in the 100-200 mm zone (0.60 and 17.97 g·kg⁻¹, respectively). Soil pH ranged from 7.05 to 8.26 across all sites. Mantel analysis indicated that vegetation metrics were significantly correlated with environmental factors as a whole (P<0.01), with groundwater depth showing the strongest association, whereas overall correlations between soil properties and vegetation indicators were not significant (P>0.05). These results demonstrate that vegetation composition and spatial patterns in the Qaidam Basin deserts are primarily controlled by water availability, while the influence of soil nutrients is relatively weak. The findings provide a scientific basis for vegetation restoration and ecological management in high-altitude arid desert regions.

Key words: Qaidam Basin, desert region, species diversity, soil nutrients

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