Functional traits and environmental adaptive characteristics of Ammopiptanthus mongolicus postprint

Abstract: To investigate the adaptive characteristics of Ammopiptanthus mongolicus, a rare and endangered species native to the desert regions of northwest China, under the context of climate change, we conducted a comprehensive analysis of the functional traits of natural A. mongolicus populations in gravelly habitats across Inner Mongolia, Ningxia Hui Autonomous Region, and Gansu Province. Using the self-calibrating Palmer Drought Severity Index ( scPDSI ), we assessed the drought conditions of the study sites and explored the functional traits of A. mongolicus and their adaptive responses to environmental factors. The study employed various methods, including GPS-based measurements of geographic coordinates and altitude, along with assessments of soil moisture, leaf structural traits, physiological and ecological indicators, and growth parameters. The results were as follows：（1）The intraspecific coefficient of variation in A. mongolicus ranged from 7.06% to 39.54%, with considerable variability observed in leaf morphology and structural composition. （2）As the study regions became increasingly humid, significant decreases were observed in leaf dry matter content, leaf thickness, petiole length, petiole dry weight, petiole fresh weight, and transpiration rate (P<0.05), while significant increases were found in leaf fresh weight, leaf length, leaf shape index, and water use efficiency (P<0.05).（3）The leaf functional traits of A. mongolicus were significantly influenced by environmental conditions, with key factors including soil sand content, average annual wind speed, soil clay content, and average annual potential evapotranspiration. （ 4 ） The plant trait networks (PTNs) of A. mongolicus exhibited a loosely structured yet locally clustered configuration in sandy habitats, while in gravelly habitats, traits were more coordinated. These findings suggest that the development of leaf traits in A. mongolicus is a complex process shaped by the interaction of multiple environmental factors. A. mongolicus adapts to different habitats by modulating trait modules, either coordinating traits as a whole or differentiating them into distinct modules to mitigate water stress in arid environments. In summary, A. mongolicus demonstrates distinct functional traits and adaptive strategies under varying environmental conditions, with these traits significantly influenced by environmental factors. This study provides scientific insights into the mechanisms of environmental adaptation in A. mongolicus and serves as a reference for formulating conservation and restoration strategies for this endangered species.