Field (CO2)-C-13 pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a Kobresia meadow

NWIPB OpenIR

	Field (CO2)-C-13 pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a Kobresia meadow
	Zou, J. ; Zhao, L. ; Xu, S. ; Xu, X. ; Chen, D. ; Li, Q. ; Zhao, N. ; Luo, C. ; Zhao, X.
	2014
发表期刊	BIOGEOSCIENCES ; Zou, J; Zhao, L; Xu, S; Xu, X; Chen, D; Li, Q; Zhao, N; Luo, C; Zhao, X.Field (CO2)-C-13 pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a Kobresia meadow,BIOGEOSCIENCES,2014,11(16):4381
摘要	Livestock exclosure has been widely used as an approach for grassland restoration. However, the effects of exclosures on grasslands are controversial and can depend on many factors, such as the grassland ecosystem types, evolutionary history and so on. In this study, we conduct field experiments to investigate the variations of the ecosystem function in response to livestock exclosure in a Kobresia humilis meadow with 6 years of grazing exclosure on the Qinghai-Tibetan Plateau. We focused on two ecosystem functions: plant community structure and ecosystem carbon cycling. The plant aboveground productivity, plant diversity and the composition of plant functional groups of the meadow were addressed as the indicators of the plant community structure. The C-13 isotope pulse labeling technique was applied to evaluate the alterations of ecosystem carbon cycling during a short term. The results showed that the plant community structure was changed after being fenced in for 6 years, with significantly decreased aboveground productivity, species loss and varied composition of the four plant functional groups (grasses, sedges, legumes and forbs). Using the pulse labeling technique, we found a lower cycling rate of C-13 in the plant-soil system of the fenced plots compared with the grazed sites during the first 24 h after labeling. A higher proportion of recovered C-13 in the plant-soil system migrated into the soil as root exudates immediately after labeling at both fenced and control grazed sites, with a significantly lower proportion in the fenced site, coinciding with the lower proportion of C-13 lost from soil respiration. Thirtytwo days after labeling, 37% of the recovered C-13 remained in the soil of the fenced plots, with significant differences compared to in the grazed plots (47 %). In addition, less C-13 (5 vs. 7 %) was lost by soil respiration in the fenced plots during the chase period of 32 days. Overall, our study suggests that livestock exclosures have negative effects on the plant community structure and partitioning patterns of the photoassimilated carbon in the Kobresia meadow, and the effects on photoassimilated carbon cycling are likely to result from the variations of community structures in the ecosystem.; Livestock exclosure has been widely used as an approach for grassland restoration. However, the effects of exclosures on grasslands are controversial and can depend on many factors, such as the grassland ecosystem types, evolutionary history and so on. In this study, we conduct field experiments to investigate the variations of the ecosystem function in response to livestock exclosure in a Kobresia humilis meadow with 6 years of grazing exclosure on the Qinghai-Tibetan Plateau. We focused on two ecosystem functions: plant community structure and ecosystem carbon cycling. The plant aboveground productivity, plant diversity and the composition of plant functional groups of the meadow were addressed as the indicators of the plant community structure. The C-13 isotope pulse labeling technique was applied to evaluate the alterations of ecosystem carbon cycling during a short term. The results showed that the plant community structure was changed after being fenced in for 6 years, with significantly decreased aboveground productivity, species loss and varied composition of the four plant functional groups (grasses, sedges, legumes and forbs). Using the pulse labeling technique, we found a lower cycling rate of C-13 in the plant-soil system of the fenced plots compared with the grazed sites during the first 24 h after labeling. A higher proportion of recovered C-13 in the plant-soil system migrated into the soil as root exudates immediately after labeling at both fenced and control grazed sites, with a significantly lower proportion in the fenced site, coinciding with the lower proportion of C-13 lost from soil respiration. Thirtytwo days after labeling, 37% of the recovered C-13 remained in the soil of the fenced plots, with significant differences compared to in the grazed plots (47 %). In addition, less C-13 (5 vs. 7 %) was lost by soil respiration in the fenced plots during the chase period of 32 days. Overall, our study suggests that livestock exclosures have negative effects on the plant community structure and partitioning patterns of the photoassimilated carbon in the Kobresia meadow, and the effects on photoassimilated carbon cycling are likely to result from the variations of community structures in the ecosystem.
文献类型	期刊论文
条目标识符	http://210.75.249.4/handle/363003/52678
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	Zou, J.,Zhao, L.,Xu, S.,et al. Field (CO2)-C-13 pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a Kobresia meadow[J]. BIOGEOSCIENCES, Zou, J; Zhao, L; Xu, S; Xu, X; Chen, D; Li, Q; Zhao, N; Luo, C; Zhao, X.Field (CO2)-C-13 pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a Kobresia meadow,BIOGEOSCIENCES,2014,11(16):4381,2014.
APA	Zou, J..,Zhao, L..,Xu, S..,Xu, X..,Chen, D..,...&Zhao, X..(2014).Field (CO2)-C-13 pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a Kobresia meadow.BIOGEOSCIENCES.
MLA	Zou, J.,et al."Field (CO2)-C-13 pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a Kobresia meadow".BIOGEOSCIENCES (2014).