气候变化领域集成服务门户(CCPortal): Grazing exclusion enhanced net ecosystem carbon uptake but decreased plant nutrient content in an alpine steppe

CCPortal

DOI	10.1016/j.catena.2020.104799
	Grazing exclusion enhanced net ecosystem carbon uptake but decreased plant nutrient content in an alpine steppe
	Liu, Yongwen; Tenzintarchen; Geng, Xiaodong; Wei, Da; Dai, Dongxue; Xu-Ri
通讯作者	Liu, YW ; Xu-Ri (通讯作者)
发表日期	2020
ISSN	0341-8162
EISSN	1872-6887
卷号	195
英文摘要	Grazing exclusion is widely conducted to restore degraded grasslands. The recovery status can be indicated by both nutrient and carbon cycling. However, the effect of grazing exclusion on net ecosystem CO2 exchange and mineral nutrients in pastures on the Tibetan Plateau remains unclear, due to a lack of in situ investigations. Here, we conducted an in situ investigation of the grazing exclusion effect on net ecosystem CO2 exchange and foliar mineral elements in an alpine steppe on the central Tibetan Plateau. Our results show that seven years of grazing exclusion enhanced net CO2 uptake by 17% during the growing season via increased gross ecosystem photosynthesis, rather than unchanged ecosystem respiration. Grazing exclusion reduced the sensitivity of ecosystem respiration to soil surface temperature by 16-17% at both diurnal and seasonal scales. Grazing exclusion, therefore, may be an effective way to enhance carbon sequestration under the background of a warming climate. We further found that grazing exclusion significantly decreased the soil available nitrate-nitrogen concentration by 50% and foliar mineral concentrations such as nitrogen, calcium, sulfur, iron, and manganese. Grazing exclusion increased the foliar carbon:nitrogen ratio by 16% and decreased the foliar nitrogen:phosphorus ratio by 15%. These results indicate that grazing exclusion enhanced net ecosystem CO2 uptake but aggravated mineral nutrient limitation of plant growth. Our study highlights that grazing exclusion influences alpine grassland carbon cycling by directly preventing grazing and by indirectly altering the status of plant nutrients. A quantitative distinction of such direct and indirect effects based on long-term and continuous in situ field observations is critical for revealing the mechanism underlying carbon-nutrient cycling evolution in the restoration of degraded alpine grasslands.
关键词	TIBETAN PLATEAU CO2 EXCHANGE NITROGEN MINERALIZATION TEMPERATURE SENSITIVITY SOIL-TEMPERATURE INNER-MONGOLIA CLIMATE-CHANGE GRASSLAND PRODUCTIVITY VEGETATION
英文关键词	Climate change; Livestock exclosure; Carbon cycle; Net ecosystem CO2 exchange; Mineral element; Nitrogen:phosphorus ratio; Alpine grassland; Rangeland degradation; Tibetan Plateau
语种	英语
WOS研究方向	Geology ; Agriculture ; Water Resources
WOS类目	Geosciences, Multidisciplinary ; Soil Science ; Water Resources
WOS记录号	WOS:000580366300046
来源期刊	CATENA
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/259859
推荐引用方式 GB/T 7714	Liu, Yongwen,Tenzintarchen,Geng, Xiaodong,et al. Grazing exclusion enhanced net ecosystem carbon uptake but decreased plant nutrient content in an alpine steppe[J]. 中国科学院青藏高原研究所,2020,195.
APA	Liu, Yongwen,Tenzintarchen,Geng, Xiaodong,Wei, Da,Dai, Dongxue,&Xu-Ri.(2020).Grazing exclusion enhanced net ecosystem carbon uptake but decreased plant nutrient content in an alpine steppe.CATENA,195.
MLA	Liu, Yongwen,et al."Grazing exclusion enhanced net ecosystem carbon uptake but decreased plant nutrient content in an alpine steppe".CATENA 195(2020).