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

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • W. Babel - , University of Bayreuth (Author)
  • T. Biermann - , Lund University (Author)
  • H. Coners - , University of Göttingen (Author)
  • E. Falge - , Johann Heinrich von Thunen Institute (Author)
  • E. Seeber - , Senckenberg Gesellschaft für Naturforschung (Author)
  • J. Ingrisch - , University of Innsbruck (Author)
  • P. M. Schleuß - , University of Göttingen (Author)
  • T. Gerken - , Pennsylvania State University (Author)
  • J. Leonbacher - , University of Bayreuth (Author)
  • T. Leipold - , University of Bayreuth (Author)
  • S. Willinghöfer - , University of Göttingen (Author)
  • K. Schützenmeister - , University of Koblenz (Author)
  • O. Shibistova - , Leibniz University Hannover (LUH), RAS - Sukachev Institute of Forest, Siberian Branch (Author)
  • L. Becker - , Leibniz University Hannover (LUH) (Author)
  • S. Hafner - , University of Göttingen (Author)
  • S. Spielvogel - , University of Göttingen, University of Koblenz (Author)
  • X. Li - , Lanzhou University (Author)
  • X. Xu - , University of Göttingen, CAS - Institute of Geographical Sciences and Natural Resources Research (Author)
  • Y. Sun - , University of Göttingen, CAS - Institute of Geographical Sciences and Natural Resources Research (Author)
  • L. Zhang - , CAS - Chinese Academy of Sciences (Author)
  • Y. Yang - , CAS - Chinese Academy of Sciences (Author)
  • Y. Ma - , CAS - Chinese Academy of Sciences (Author)
  • K. Wesche - , Chair of Biodiversity of Higher Plants, Senckenberg Museum of Natural History Görlitz, Senckenberg Gesellschaft für Naturforschung, German Centre for Integrative Biodiversity Research (iDiv) Halle—Jena—Leipzig (Author)
  • H. F. Graf - , University of Cambridge (Author)
  • C. Leuschner - , University of Göttingen (Author)
  • G. Guggenberger - , Leibniz University Hannover (LUH) (Author)
  • Y. Kuzyakov - , University of Göttingen, Kazan Volga Region Federal University (Author)
  • G. Miehe - , University of Marburg (Author)
  • T. Foken - , University of Bayreuth (Author)

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.

Details

Original languageEnglish
Pages (from-to)6633-6656
Number of pages24
JournalBiogeosciences
Volume11
Issue number23
Publication statusPublished - 2 Dec 2014
Peer-reviewedYes