Abstract:

Aims: Plant traits serve as a bridge linking plants and their environment. As the basic unit for studying this relationship, functional groups carry key information on responses to environmental changes. Investigating how the composition of plant functional groups and leaf traits vary along resource gradients is crucial for understanding the environmental adaptation strategies of desert plants. 

Methods: This study focused on the Artemisia ordosica communities in the Mu Us Sandy Land including four typical restoration stages: semi-fixed dune (D1), fixed dune (D2), fixed dune with biological soil crusts (D3), fixed dune with abundant herbaceous plants (D4). The plant communities were categorized into three functional groups: grass, non-grass herbs, and shrub. We revealed the species composition of different plant functional groups at each restoration stage, the characteristics of their leaf traits, and the key soil-driven factors, with redundancy analysis (RDA) and variation partitioning. 

Results: As the sand dunes gradually stabilize, the composition of plant functional groups became more complex, and the number of grass and non-grass species showed an increasing trend. However, shrub species showed relatively stable. The leaf traits of plant functional groups during the D1 and D2 stages exhibited higher specific leaf area and lower leaf dry matter content (LDMC), suggesting that plants prioritized investment in leaf morphological development to enhance resource utilization under harsh environmental conditions. Among these, grass had higher LDMC and carbon assimilation capacity, which enhanced their ability to adapt to stressful environments. RDA revealed that soil water content (SWC), soil carbon-to-nitrogen ratio (SC: N), and soil organic carbon content (SOC) significantly influenced the leaf trait assemblages of all three plant functional groups (P < 0.01). Variation partitioning and hierarchical partitioning analysis indicated that nine soil factors explained 18.5% of the total variance in plant leaf traits. The SC: N had the largest individual effect (4.13%), and both SC: N and SWC exhibited co-effects with most other factors. These findings contributed to a deeper understanding of the ecological adaptation strategies of desert plants and provided a theoretical basis for vegetation restoration and management in desert regions.

Key words: leaf traits, soil environmental factors, redundancy analysis, sand fixation stage, plant functional groups