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Pasture degradation modifies the water and carbon cycles of the Tibetan highlands

Babel, Wolfgang; Biermann, Tobias LU ; Coners, Heinz; Falge, Eva; Seeber, Elke; Schleuß, Per Marten; Gerken, Tobias; Leonbacher, Juergen; Leipold, Thomas and Willinghöfer, Sandra, et al. (2014) In Biogeosciences 11(23). p.6633-6656
Abstract
The Tibetan Plateau has a significant role with regard to atmospheric circulation and the monsoon in particular. Changes between a closed plant cover and open bare soil are one of the striking effects of land use degradation observed with unsustainable range management or climate change, but experiments investigating changes of surface properties and processes together with atmospheric feedbacks are rare and have not been undertaken in the world's two largest alpine ecosystems, the alpine steppe and the Kobresia pygmaea pastures of the Tibetan Plateau. We connected measurements of micro-lysimeter, chamber, 13C labelling, and eddy covariance and combined the observations with land surface and atmospheric models, adapted to the highland... (More)
The Tibetan Plateau has a significant role with regard to atmospheric circulation and the monsoon in particular. Changes between a closed plant cover and open bare soil are one of the striking effects of land use degradation observed with unsustainable range management or climate change, but experiments investigating changes of surface properties and processes together with atmospheric feedbacks are rare and have not been undertaken in the world's two largest alpine ecosystems, the alpine steppe and the Kobresia pygmaea pastures of the Tibetan Plateau. We connected measurements of micro-lysimeter, chamber, 13C labelling, and eddy covariance and combined the observations with land surface and atmospheric models, adapted to the highland conditions. This allowed us to analyse how three degradation stages affect the water and carbon cycle of pastures on the landscape scale within the core region of the Kobresia pygmaea ecosystem. The study revealed that increasing degradation of the Kobresia turf affects carbon allocation and strongly reduces the carbon uptake, compromising the function of Kobresia pastures as a carbon sink. Pasture degradation leads to a shift from transpiration to evaporation while a change in the sum of evapotranspiration over a longer period cannot be confirmed. The results show an earlier onset of convection and cloud generation, likely triggered by a shift in evapotranspiration timing when dominated by evaporation. Consequently, precipitation starts earlier and clouds decrease the incoming solar radiation. In summary, the changes in surface properties by pasture degradation found on the highland have a significant influence on larger scales. (Less)
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Biogeosciences
volume
11
issue
23
pages
6633 - 6656
publisher
Copernicus Publications
external identifiers
  • scopus:84919363203
ISSN
1726-4189
DOI
10.5194/bg-11-6633-2014
language
English
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yes
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cbbff06b-6759-4054-8e74-0f3288bbe664 (old id 7767013)
date added to LUP
2015-09-03 13:09:44
date last changed
2017-09-17 04:06:22
@article{cbbff06b-6759-4054-8e74-0f3288bbe664,
  abstract     = {The Tibetan Plateau has a significant role with regard to atmospheric circulation and the monsoon in particular. Changes between a closed plant cover and open bare soil are one of the striking effects of land use degradation observed with unsustainable range management or climate change, but experiments investigating changes of surface properties and processes together with atmospheric feedbacks are rare and have not been undertaken in the world's two largest alpine ecosystems, the alpine steppe and the Kobresia pygmaea pastures of the Tibetan Plateau. We connected measurements of micro-lysimeter, chamber, 13C labelling, and eddy covariance and combined the observations with land surface and atmospheric models, adapted to the highland conditions. This allowed us to analyse how three degradation stages affect the water and carbon cycle of pastures on the landscape scale within the core region of the Kobresia pygmaea ecosystem. The study revealed that increasing degradation of the Kobresia turf affects carbon allocation and strongly reduces the carbon uptake, compromising the function of Kobresia pastures as a carbon sink. Pasture degradation leads to a shift from transpiration to evaporation while a change in the sum of evapotranspiration over a longer period cannot be confirmed. The results show an earlier onset of convection and cloud generation, likely triggered by a shift in evapotranspiration timing when dominated by evaporation. Consequently, precipitation starts earlier and clouds decrease the incoming solar radiation. In summary, the changes in surface properties by pasture degradation found on the highland have a significant influence on larger scales.},
  author       = {Babel, Wolfgang and Biermann, Tobias and Coners, Heinz and Falge, Eva and Seeber, Elke and Schleuß, Per Marten and Gerken, Tobias and Leonbacher, Juergen and Leipold, Thomas and Willinghöfer, Sandra and Becher, Lena and Spielvogel, Sandra and Guggenberger, Georg and Schuetzenmeister, Klaus and Shibistova, Olga and Hafner, Silke and Li, Xiaogang and Xu, Xingliang and Yang, Yongping and Ma, Yaoming and Wesche, Karsten and Graf, Hans-F. and Leuschner, Christoph and Kuzyakov, Yakov and Miehe, Georg and Foken, Thomas},
  issn         = {1726-4189},
  language     = {eng},
  number       = {23},
  pages        = {6633--6656},
  publisher    = {Copernicus Publications},
  series       = {Biogeosciences},
  title        = {Pasture degradation modifies the water and carbon cycles of the Tibetan highlands},
  url          = {http://dx.doi.org/10.5194/bg-11-6633-2014},
  volume       = {11},
  year         = {2014},
}