Spatiotemporal dynamics and adaptive strategies of plant diversity and functional traits in desert steppe.

Introduction: Plant diversity and functional traits form the core foundation of grassland ecosystem stability. However, rapid climate change poses a severe threat to biodiversity, making it imperative to clarify how these two factors mediate community responses to environmental changes across spatiotemporal scales. Methods: By integrating field surveys with laboratory analyses, we have investigated the spatiotemporal patterns of plant diversity and key functional traits within desert grasslands of the Ili River Basin. Results: We found that: (1) Plant diversity in May and July was significantly higher than in September, with distinct seasonal dynamics observed across different plant community types; (2) During the main growing season, plant functional traits exhibited a marked increasing trend along the elevation gradient; (3) Both plant functional traits and diversity displayed a patchy mosaic distribution pattern, accompanied by significant spatial heterogeneity. High diversity values were predominantly located around Nilek and Huocheng counties, while low-value areas were distributed in Xinyuan and Gongliu counties. High-value areas for plant functional traits were concentrated in Nilek county, with low-value areas found in Xinyuan, Gongliu, and Huocheng counties. (4) Redundancy Analysis (RDA) and Structural Equation Modeling (SEM) indicate that soil moisture content and soil nitrogen are the primary drivers of diversity variation, while soil carbon-to-nitrogen ratio and precipitation regulate functional trait variation. Discussion: These findings demonstrate how plants adapt to environmental heterogeneity through coordinated changes in diversity and functional traits, offering a scientific basis for conserving and managing desert steppe ecosystems.