Effects of Drought on Ecosystem Carbon and Water Processes: a Review at Differ ent Scales
干旱对陆地生态系统水碳过程的影响研究进展

In the background of global climate change, the effect of drought on ecosystem structure and function has been paid more and more attention to. In this paper, for the purpose of presenting approaches to elucidate the mechanism of drought effects on ecosystem processes, we reviewed the effects of drought on carbon/water processes at individual level and community level. At the individual level, drought can make plant change its physiological and morphological traits to conserve water, such as decreasing stomata conductance, increasing solute content, changing stomata density and size, increasing specific leaf area and belowground biomass allocation, etc. In addition, different plants have different water-use strategies. Their physiological and morphological traits responding to drought are apparently distinct. At the community level, similarly, drought can change vegetations physiology and structure, such as photosynthesis, respiration, transpiration, water use efficiency, biodiversity, productivity et al. Despite that most aspects of drought effects on ecosystem are included in current studies, they are isolated from each other. To fully understand how ecosystem responds to drought, it is essential to combine all methods available, to synthetically study the processes coupling with each other (e.g. carbon cycle, water cycle and nitrogen cycle), and to construct a theoretical system to connect different time scales ( from minute to decade) and levels (from leaf to ecosystem).