Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow
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 t...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-08-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/4381/2014/bg-11-4381-2014.pdf |
| _version_ | 1831736249302384640 |
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| author | J. Zou L. Zhao S. Xu X. Xu D. Chen Q. Li N. Zhao C. Luo X. Zhao |
| author_facet | J. Zou L. Zhao S. Xu X. Xu D. Chen Q. Li N. Zhao C. Luo X. Zhao |
| author_sort | J. Zou |
| collection | DOAJ |
| description | 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 <i>Kobresia humilis</i> 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 <sup>13</sup>C 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 <sup>13</sup>C 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 <sup>13</sup>C 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 <sup>13</sup>C lost from soil respiration. Thirty-two days after labeling,
37% of the recovered <sup>13</sup>C remained in the soil of the fenced plots, with
significant differences compared to in the grazed plots (47%). In addition,
less <sup>13</sup>C (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
<i>Kobresia</i> meadow, and the effects on photoassimilated carbon cycling
are likely to result from the variations of community structures in the
ecosystem. |
| first_indexed | 2024-12-21T12:41:12Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-21T12:41:12Z |
| publishDate | 2014-08-01 |
| publisher | Copernicus Publications |
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| series | Biogeosciences |
| spelling | doaj.art-e2af1d80d2ed418396e28ac386a7d3932022-12-21T19:03:47ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-08-0111164381439110.5194/bg-11-4381-2014Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadowJ. Zou0L. Zhao1S. Xu2X. Xu3D. Chen4Q. Li5N. Zhao6C. Luo7X. Zhao8Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, ChinaKey Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, ChinaKey Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, ChinaKey Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographical Sciences & Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaKey Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, ChinaKey Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, ChinaKey Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, ChinaKey Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, ChinaKey Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, ChinaLivestock 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 <i>Kobresia humilis</i> 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 <sup>13</sup>C 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 <sup>13</sup>C 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 <sup>13</sup>C 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 <sup>13</sup>C lost from soil respiration. Thirty-two days after labeling, 37% of the recovered <sup>13</sup>C remained in the soil of the fenced plots, with significant differences compared to in the grazed plots (47%). In addition, less <sup>13</sup>C (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 <i>Kobresia</i> meadow, and the effects on photoassimilated carbon cycling are likely to result from the variations of community structures in the ecosystem.http://www.biogeosciences.net/11/4381/2014/bg-11-4381-2014.pdf |
| spellingShingle | J. Zou L. Zhao S. Xu X. Xu D. Chen Q. Li N. Zhao C. Luo X. Zhao Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow Biogeosciences |
| title | Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow |
| title_full | Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow |
| title_fullStr | Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow |
| title_full_unstemmed | Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow |
| title_short | Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow |
| title_sort | field sup 13 sup co sub 2 sub pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a i kobresia i meadow |
| url | http://www.biogeosciences.net/11/4381/2014/bg-11-4381-2014.pdf |
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