Non‑linear responses of life‑history strategies to warming in arid desert herbaceous plants

• Desert herbs responded non-linearly to warming. • Moderate warming increased biomass allocation to stem, leaf and reproduction. • Extreme warming increased biomass allocation to roots. • Optimal partitioning theory and r - and K -selection predict plant dynamics. Plant life-history strategy involves a trade-off among survival, growth, and reproduction, influenced not only by their inherent capacity but also by prevailing environments. Climate warming and the following environmental changes are likely to rapidly reshape plant resource acquisition and allocation strategies, particularly for desert plants, which are already pushed to the limits of their physiological tolerances. Here, a three-year in situ warming experiment was conducted through the open-top chambers (OTCs), with air temperature increases of 0.9 °C, 1.2 °C, and 1.6 °C, respectively. This study aimed to examine the effects of different warming scenarios on plant growth, biomass allocation, and reproduction in Grubovia dasyphylla and Allium mongolicum , as well as to assess the coordination among trait responses. The results demonstrated that desert herbs exhibited non-linear responses to climate warming. Plant growth and reproductive traits were enhanced in 0.9 °C and 1.2 °C warming but declined in 1.6 °C warming. Additionally, plants allocated fewer resources to roots in 0.9 °C and 1.2 °C warming, while reallocating more resources to roots and reducing reproductive investment in 1.6 °C warming. Furthermore, plant traits coordination decreased across all three warming scenarios. These shifts in life-history strategies were primarily driven by changes in soil moisture and nutrient availability resulting from experimental warming. These findings revealed non-linear responses of plant life-history strategies under different warming scenarios, highlighting warming intensity as a critical determinant of plant growth and reproductive success in desert ecosystems. These findings have important implications for forecasting vegetation dynamics and ecosystem structures in deserts under future climate scenarios.