Soil properties rather than climate dominate the variation of leaf trait network structure in desert ecosystems: a case study from the Hexi Corridor, Northwestern China

Leaf trait networks (LTNs) can reveal complex relationships among multiple traits, and their topological structure reflects plant adaptation to the environment. However, the main environmental drivers and underlying mechanisms of spatial variation in LTN structure remain insufficiently studied, particularly in desert ecosystems. To this end, this study selected 15 typical desert sites along the southeast to northwest of the Hexi Corridor, constructed LTNs based on 20 leaf functional traits, and used geography, climate, soil, and plant diversity as environmental factors to assess their relationships with the network structure. The results showed that LTN structure varied greatly among sites, exhibiting significant spatial heterogeneity. Moreover, for different plant life forms, the network topology of herbaceous species was more tightly connected than that of shrubs, suggesting that herbs rely more on multi-trait coordination to improve resource-use efficiency. Among all environmental factors, soil properties had the greatest influence on LTN variation, with higher soil nutrients significantly enhancing network connectivity and complexity, while geographic and climatic factors had weaker direct effects. Partial least squares path modeling further revealed that soil properties had significant direct effects on LTN structure, whereas climate and geography influenced it indirectly through plant diversity. This study highlights the key role of soil properties in regulating LTNs in desert ecosystems and provides insights into how multi-trait trade-offs are reshaped and optimized in resource-heterogeneous communities.