DOI: 10.1016/j.jenvman.2026.130022

发表期刊：Journal of Environmental Management

链接：https://doi.org/10.1186/s12864-025-11241-5

作者：Dongming Chen, Muhammad Ibrar, Fei Yana, Geng Sun, Ran Xue, Aomei Jia, Jiqiong Zhou, Yongheng Gao, Congyu Ma, Meng Wang, Jian Zhang*, Zhouwen Ma*, Lin Liua*

Abstract: Desertification-induced soil organic carbon (SOC) loss poses a major environmental threat to the alpine grasslands of the Qinghai-Tibet Plateau, jeopardizing ecological security and sustainability. While pioneer shrub introduction has yielded positive ecological outcomes, the mechanisms of SOC recovery remain poorly understood. We investigated the effects of a widely used dioecious shrub on rhizosphere SOC dynamics across a 20-year restoration chronosequence, employing a comprehensive framework that combined root exudation measurements, soil physicochemical analysis, metagenomics, and biomarker profiling to decipher the mechanism. Our results reveal that microbial-derived carbon dominated rhizosphere SOC accrual, contributing 20.1-22.0% to the total SOC pool, over 50 times more than plant-derived carbon (0.1-0.4%). The microbial pool was predominantly fungal necromass (>93%), correlated with declining root exudation and suppressed carbon-degrading gene abundance during restoration. In the 20th year after recovery, a striking divergence in the effects of male and female shrubs on rhizosphere SOC became apparent, with female shrubs sustaining 15% more microbial necromass and 47% more lignin phenols than males. Our findings highlight that SOC restoration in the rhizosphere of pioneer shrubs is predominantly driven by a fungal-mediated microbial carbon pump. Moreover, the preferential use of female shrubs offers a dual benefit: enhancing long-term rhizosphere SOC sequestration and controlling shrubs encroachment. This sex-informed strategy therefore provides a scalable framework for degraded alpine grasslands and serves as a transferable model for other drylands undergoing warming–wetting transitions, where alleviated water limitation increasingly enables vegetation–microbe-mediated carbon stabilization.

Keywords: Soil organic carbon; Sexual dimorphism; Fungal necromass; Carbon cycling genes; Recovery years