Status of Stipa breviflora as the constructive species will be lost under climate change in the temperate desert steppe in the future

Abstract

Climate change affects the structure and composition of a plant community and the stability and service functions of grassland ecosystems. However, the influence of warming, increased precipitation and their interaction on plant functional traits in the desert steppe are unclear. Therefore, after simulating warming (ambient temperature, warming 2℃ and warming 4℃) and increasing precipitation (natural precipitation, precipitation increased by 25% and 50%) for 6 years, we measured the morphological characteristics, photosynthesis parameters, carbon (C) and nitrogen (N) contents of leaves of Stipa breviflora Griseb. (S. breviflora), a constructive species in the desert steppe. Results showed that both warming and increased precipitation reduced the importance value (IV) of S. breviflora, while the IV of annual herbs significantly increased (P < 0.05). Warming, increased precipitation and their interactions all improve the adaptability of S. breviflora functional traits and have a positive impact on its IV, which indicates that climate change is beneficial to the growth of S. breviflora. However, a structural equation model based on ANOVA analysis and correlation analysis showed that a sharp decrease in the density of S. breviflora due to warming was the main reason for decreasing its IV in our study (P < 0.05). Warming promotes intensified competition among species, and annual herbs have an advantage in the competition. Therefore, our research reveals the succession strategy of S. breviflora and provides a theoretical basis for studying the response mechanisms of desert steppe plant communities to climate change.

Keywords

• Climate change
• Desert steppe
• Stipa breviflora
• Importance value
• Plant functional traits