Divergent water use strategies of three desert shrubs on the Alxa plateau: insights from stable isotopes and root distribution analysis

Introduction: Understanding how desert shrubs partition water sources is critical for predicting ecosystem responses to increasing drought and guiding restoration efforts in arid regions. However, the water use strategies of coexisting shrubs in cold deserts remain poorly resolved, particularly under varying soil moisture conditions. Methods: C analysis and root distribution measurements. The Bayesian mixing model (MixSIAR) was used to estimate the proportional contributions of six soil layers to plant water uptake under wet, moderate, and dry soil moisture conditions. Results: C values confirmed a depth-water use efficiency (WUE) trade-off, with deeper-rooted species exhibiting higher intrinsic WUE. Discussion: for microsites that episodically concentrate surface water. Such species-site matching can enhance restoration success under projected drier climates.