黄土高原人工柠条灌丛水分利用特征及其生长衰退成因

人工柠条林是黄土高原生态恢复的主要灌木物种，对区域生态环境改善、植被恢复建设发挥了重要作用。受气候暖干化和柠条强烈耗水导致的水分亏缺，造成柠条生长受限，并出现大面积衰退和死亡现象。因而，干旱半干旱环境下的柠条灌丛群落面对干旱胁迫如何进行水分汲取的适应性调整，以及生长后期出现衰退的机制如何，值得广泛研究。本项目拟以黄土高原人工柠条林为研究对象，通过传统生态学、稳定同位素技术及灌木年轮解剖学的理论与方法，明晰样地和样带尺度随林龄、降水梯度的人工柠条林水分利用策略，依据定位观测站柠条林的生理生态学监测，从基部（根部）到地上茎干分析柠条灌丛年轮导管解剖结构特征，揭示人工柠条林的导水能力及其限制性生态因素，最终从水分利用角度阐明其对干旱半干旱环境的适应特征及其在生长后期出现生长衰退的生态学机理。本项目对气候变化背景下黄土高原主要人工灌木植被的恢复管理及黄河流域生态保护和高质量发展具有重要的指导意义。

Caragana korshinskii is the main shrub species for ecological restoration in the Loess Plateau, which plays a significant role in the improvement of regional ecological environment and vegetation restoration. However, water deficit caused by climate change and intense water consumption of Caragana korshinskii shrubs has resulted in widespread growth decline and mortality phenomenon. Therefore, how does the Caragana shrub community adapt to the drought stress and why does it decline at the later growth stage deserve extensive research. Based on the traditional ecology, stable isotope technique and shrub rings anatomy, this project intends to reveal the water use strategy by Caragana shrubs with stand age and precipitation gradient at the stand and transect scale, respectively. According to the situ physiological and ecological monitoring, the shrub ring vessel anatomy will be analyzed from belowground root to aboveground stem to reveal the water conductivity and its limited factors in controlling Caragana shrub growth. Ultimately, we want to illustrate the adaptive characteristics of Caragana shrub to arid and semi-arid environment and the ecological mechanism of growth decline in the late growth period from the perspective of water use. In the context of the global climate change, it is of great guiding significance not only for the restoration and management of the main artificial shrub vegetation in the Loess Plateau, but also for the ecological protection and high-quality development in the Yellow River Basin.