Responses of leaf functional traits to soil environment at different sand fixation stages in the Mu Us desertland

Leaf functional traits (LFTs) can directly or indirectly reflect the adaptation strategy of plants to the environment, influencing their survival, growth, and reproduction. However, there is still uncertainty as to the relationship between LFTs and environmental gradients, especially in resource-limited regions. In this study, we selected Artemisia ordosica communities as the research objects at four different dune fixation stages, including semi-fixed (D1), fixed (D2), soil-crust fixed (D3) and herbaceous-plant-covered fixed sand dunes (D4) in Mu Us Desert. Based on field investigation and laboratory analysis, we examined the characteristics of 13 LFTs and the relationship between of LFTs trade-offs and soil physicochemical environment under different dune fixation stages. It was found that (1) in community level, leaf area (LA) and specific leaf area (SLA) were the largest at D1, while leaf tissue density (LTD) and leaf dry matter content (LDMC) shown gradually increasing trend with dune fixation. The results indicated that plants will adapt to progressively increasing competition by reducing their photosynthetic capacity and enhancing their physical defense structures. (2) with ongoing dune fixation, the soil organic carbon content (SOC) and soil total nitrogen content (STN) were significantly higher in D2-D4 than that in D1, and soil water content (SWC) was the highest in D2, then decreased significantly in D3-D4 with increasing community species. (3) according to the results of redundancy analysis (RDA), the two main axes represented the soil physical condition (54.11%) and chemical condition (30.06%), respectively. And the SWC and SOC were the main factors affecting changes in LFTs during the dune fixation. Our results provide theoretical basis for understanding the resource use strategy and adaptation mechanism of desert plants under stress environments.