摘要
陆地生态系统与大气之间的CO2净气体交换(net ecosystem exchange of carbon dioxide,NEE)被称为生物圈的呼吸,它是陆地生态系统碳循环的重要组分,是全球气候变化研究的重点。草地生态系统是陆地生态系统的主体,约占陆地表面的40%,是气候变化的敏感区域。放牧是草地生态系统的主要利用方式,伴随着气候变化,放牧利用强度不同,对草地生态系统NEE的影响也不同。本文以放牧草地生态系统NEE组成为基础,从放牧干扰途径出发,综述了放牧对草地生态系统CO2净气体交换特征的影响。放牧主要干扰草地土壤-植被界面,通过影响植物群落组成、地上净初级生产力、地下净初级生产力来影响植被群落的光合作用和呼吸作用,使草地生态系统的NEE发生变化;放牧也可通过影响土壤包括土壤呼吸、土壤养分以及土壤温度和水分来影响NEE。放牧干扰途径的研究亦可应用于草地开垦和刈割等利用方式中,这对了解和研究草地不同利用方式下生态系统的CO2交换特征、草地碳源或碳汇的转换状态,以及草地碳贮存功能的强弱具有重要意义。
The net ecosystem exchange of carbon dioxide （NEE） between terrestrial ecosystems and atmos- phere is a major component of carbon cycle of terrestrial ecosystems called ＂breathing＂ of the terrestrial bi- osphere, and is great concerned in the research of global climate change. Grasslands, as a major compo- nent of the terrestrial ecosystems, comprising approximately 40 % of the world＇s terrestrial surface, is sen- sitive to climate change. Grazing plays a significant role in the land use and management of grasslands. With the change in global climate, the impacts o＇f different grazing intensities on grazing ecosystems have different ways. In this review, the effects of grazing on the characteristics of NEE in grassland ecosystems are focused in general based on factors in NEE composition and the pathways of grazing effects on NEE in grasslands. Grazing mainly disturbs the soil-vegetation interface of grasslands then affects grassland NEE through the disturbances on 1） plant, including effects on plant community composition, above and below- ground net primary production and litter~ 2） soil, including the effects on soil respiration, soil nutrients especially soil carbon and nitrogen, soil temperature and moisture. The pathways of grazing effects on grasslands can also be applied in disturbances such as cultivation and defoliation and is of great importance in the investigating of NEE characters and carbon flux of different grassland ecosystems, particularly grasslands in different land-use, whether in carbon source or sink in certain degrees and their carbon stor- age capacity.
出处
《草地学报》
CAS
CSCD
北大核心
2013年第1期3-10,共8页
Acta Agrestia Sinica
基金
公益性行业(农业)科研专项经费(200903060)(201003019)资助
关键词
碳通量
生态系统呼吸
草地
放牧
净初级生产力
Carbon flux
Ecosystem respiration
Grassland
Grazing
Net primary productivity
