草原灌丛化是干旱/半干旱区最重要的植被类型变化方式，严重影响草原及畜牧业生产的可持续发展，是全球干旱/半干旱区面临的重要生态问题。研究草原灌丛化发展过程中各阶段灌丛群落根系的分布特征，有助于揭示驱动或限制草原灌丛化过程的内在机制，对于草原退化治理和恢复具有实践意义。受传统根系调查方法的制约，群落尺度上的灌木根系空间分布特征的野外观测研究极为缺乏。本研究拟采用探地雷达技术，开发多频率探地雷达数据融合及根目标自动识别和提取的方法。在此基础上，应用探地雷达多个频率天线系统对内蒙古草原灌丛化过程中，不同发展阶段灌丛群落根系进行监测，恢复重建灌丛群落地下根系三维构型，进而获取灌丛斑块尺度上的根系空间分布特征。再结合地上部分生态参数的系统调查，揭示地下根系在灌丛化过程中的作用及其与地上部分的相互关系，为阐明干旱/半干旱区草原灌丛化过程的内在作用机制提供理论依据。

Shrub encroachment is the most important change ways of plant community composition in arid and semi-arid grasslands. With its serious implications on local husbandry economies, this phenomenon has become a significant ecological problem around the world. Investigation of the spatial distribution characteristics of shrub community root system at different stages of encroachment not only reveals the intrinsic driving or limiting mechanisms on shrub encroachment but also has a practical significance in the degenerated pasture restoration. However, limited by the traditional root investigation methods in field, quantitative studies in root spatial distribution characteristics of shrub community are so far seriously insufficient. In this project, a signal fusion method for multiple-frequency GPR data and an automatic recognition algorithm for GPR images of root detection will be developed. Ground-penetrating radar (GPR), with multiple-frequency antenna system, will be used to detect the root system of shrub community at different stages of encroachment. And then a noninvasive method for reconstruction root system architecture of shrub community will be established. Based on this, the spatial distribution characteristics of shrub community root system at different stages of encroachment will be acquired. Combining with Up-ground ecological parameters of shrub community measured, the interrelation of below- and up-ground of shrub community will be revealed. This project will enhance the noninvasive study of plant root in field. Findings in this project are of great scientific interest in understanding the intrinsic mechanisms of shrub encroachment and the protection of the grassland ecosystem in future.