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Carbon balance of a grazed savanna grassland ecosystem in South Africa

Räsänen, Matti; Aurela, Mika; Vakkari, Ville; Beukes, Johan P.; Tuovinen, Juha-Pekka; Van Zyl, Pieter G.; Josipovic, Miroslav; Venter, Andrew D.; Jaars, Kerneels and Siebert, Stefan J., et al. (2017) In Biogeosciences 14(5). p.1039-1054
Abstract

Tropical savannas and grasslands are estimated to contribute significantly to the total primary production of all terrestrial vegetation. Large parts of African savannas and grasslands are used for agriculture and cattle grazing, but the carbon flux data available from these areas are limited. This study explores carbon dioxide fluxes measured with the eddy covariance method for 3 years at a grazed savanna grassland in Welgegund, South Africa. The tree cover around the measurement site, grazed by cattle and sheep, was around 15 %. The night-time respiration was not significantly dependent on either soil moisture or soil temperature on a weekly temporal scale, whereas on an annual timescale higher respiration rates were observed when... (More)

Tropical savannas and grasslands are estimated to contribute significantly to the total primary production of all terrestrial vegetation. Large parts of African savannas and grasslands are used for agriculture and cattle grazing, but the carbon flux data available from these areas are limited. This study explores carbon dioxide fluxes measured with the eddy covariance method for 3 years at a grazed savanna grassland in Welgegund, South Africa. The tree cover around the measurement site, grazed by cattle and sheep, was around 15 %. The night-time respiration was not significantly dependent on either soil moisture or soil temperature on a weekly temporal scale, whereas on an annual timescale higher respiration rates were observed when soil temperatures were higher. The carbon dioxide balances of the years 2010-2011, 2011-2012 and 2012-2013 were-85 ± 16, 67 ± 20 and 139 ± 13 gC m-2yr-1, respectively. The yearly variation was largely determined by the changes in the early wet season fluxes (September to November) and in the mid-growing season fluxes (December to January). Early rainfall enhanced the respiratory capacity of the ecosystem throughout the year, whereas during the mid-growing season high rainfall resulted in high carbon uptake.

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Biogeosciences
volume
14
issue
5
pages
16 pages
publisher
Copernicus Publications
external identifiers
  • scopus:85014889493
  • wos:000396168900001
ISSN
1726-4170
DOI
10.5194/bg-14-1039-2017
language
English
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yes
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9063d6ad-69a4-46a5-94e5-e2ab63612c25
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2017-03-23 09:46:56
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2018-01-07 11:56:46
@article{9063d6ad-69a4-46a5-94e5-e2ab63612c25,
  abstract     = {<p>Tropical savannas and grasslands are estimated to contribute significantly to the total primary production of all terrestrial vegetation. Large parts of African savannas and grasslands are used for agriculture and cattle grazing, but the carbon flux data available from these areas are limited. This study explores carbon dioxide fluxes measured with the eddy covariance method for 3 years at a grazed savanna grassland in Welgegund, South Africa. The tree cover around the measurement site, grazed by cattle and sheep, was around 15 %. The night-time respiration was not significantly dependent on either soil moisture or soil temperature on a weekly temporal scale, whereas on an annual timescale higher respiration rates were observed when soil temperatures were higher. The carbon dioxide balances of the years 2010-2011, 2011-2012 and 2012-2013 were-85 ± 16, 67 ± 20 and 139 ± 13 gC m<sup>-2</sup>yr<sup>-1</sup>, respectively. The yearly variation was largely determined by the changes in the early wet season fluxes (September to November) and in the mid-growing season fluxes (December to January). Early rainfall enhanced the respiratory capacity of the ecosystem throughout the year, whereas during the mid-growing season high rainfall resulted in high carbon uptake.</p>},
  author       = {Räsänen, Matti and Aurela, Mika and Vakkari, Ville and Beukes, Johan P. and Tuovinen, Juha-Pekka and Van Zyl, Pieter G. and Josipovic, Miroslav and Venter, Andrew D. and Jaars, Kerneels and Siebert, Stefan J. and Laurila, Tuomas and Rinne, Janne and Laakso, Lauri},
  issn         = {1726-4170},
  language     = {eng},
  month        = {03},
  number       = {5},
  pages        = {1039--1054},
  publisher    = {Copernicus Publications},
  series       = {Biogeosciences},
  title        = {Carbon balance of a grazed savanna grassland ecosystem in South Africa},
  url          = {http://dx.doi.org/10.5194/bg-14-1039-2017},
  volume       = {14},
  year         = {2017},
}