降水、氮沉降及放牧对草地生态系统凋落物分解的影响研究进展

Research Advances on the Effects of Precipitation,Nitrogen Deposition and Grazing on Litter Decomposition in Grassland Ecosystem

草地生态系统对我国建设生态文明、提供生态系统服务、保障食品安全和维护边疆稳定有举足轻重的作用。全球气候变化和过度的人为干扰打破了草地生态系统原有的平衡及稳定性,造成草地退化、沙化和盐渍化现象严重。草地生态系统结构、功能与过程的稳定是保证草地生态系统稳定的基础。凋落物分解过程是草地物质循环的重要环节,对维持草地生态系统稳定性具有重要作用。草地生态系统凋落物分解对降水格局变化、大气氮沉降增加及放牧干扰的响应已有较多的研究。对目前国内外相关研究进行了梳理和总结,发现降水、氮沉降和放牧对草地生态系统凋落物分解的影响,因地理位置和气候变化以及草地类型的异质性而不同,也有针对同一地区开展的研究呈现不同结果的现象。目前对这三种干扰因素中的两因素或三因素交互作用对草地生态系统凋落物分解过程的影响研究较少,而研究气候变化及人为干扰对草地生态系统凋落物的影响对正确理解草地生态系统结构与功能,以及可持续利用与保护草地生态系统具有重要的意义。

Grassland ecosystem plays important roles in construction of ecological civilization,provision of ecosystem service,guarantee of food safety,and maintenance of border stability in China.Global climate change and excessive human disturbance have broken the original balance and stability of grassland ecosystem,and resulted in serious grassland degradation,desertification and salinization.The stability of structure,function and process of grassland ecosystem is fundamental to protect its steadiness.The litter decomposition is an important part in the grass material cycle and is of great significance to maintain the stability of grassland ecosystem.The responses of litter decomposition in grassland ecosystem to precipitation pattern change,increased atmospheric nitrogen deposition and grazing interference have been widely reported.By generalizing the related researches in China and abroad,we found that the results of studies on effects of precipitation,nitrogen deposition and grazing on litter decomposition in grassland ecosystem varied due to the geographical location,climate change and heterogeneity of grassland types,and even the same region had different findings.At present,there is limited information regarding the impacts of interactions of the above mentioned two or three interference factors on litter decomposition process of grassland ecosystem.It is of great significance to assess the effects of climate change and human disturbance on grassland ecosystem litter for the correct understanding of the structure and function of grassland ecosystem,as well as the sustainable utilization and protection of grassland ecosystem.