Issues and prospects of belowground ecology with special reference to global climate change

The theory of ecology is based on over 100 a of research and investigation, all centered on aboveground pat-terns and processes. However, as contemporary ecologists are increasingly acknowledging, belowground structures, func-tions, and processes are some of the most poorly understood areas in ecology. This lack of understanding of belowground ecological processes seriously restricts the advance of global change research. The interdisciplinary field of belowground ecology began to flourish in the 1990s, along with the expan-sion of global change research, and quickly gained momen-tum. Belowground ecology aims to investigate belowground structures, functions, and processes, as well as their rela-tionships with corresponding aboveground features, empha-sizing the responses of belowground systems under global change conditions. Key research areas include root ecology, belowground animals, and soil microorganisms. This review summarizes and analyzes the relationships between above- and belowground ecosystems, root ecology, root biogeogra-phy, belowground biodiversity, as well as research areas with particular challenges and progress. This commentary em-phasizes certain theoretical issues concerning the responses of belowground processes to global change, and concludes that belowground ecology is a critical research priority in the 21st century.