Soil Methane Uptake Increases under Continuous Throughfall Reduction in a Temperate Evergreen, Broadleaved Eucalypt Forest
- 365 Downloads
Soils in temperate forests ecosystems are the greatest terrestrial CH4 sink globally. Global and regional circulation models predict decreased average rainfall, increased extreme rainfall events and increased temperatures for many temperate ecosystems. However, most studies of soil CH4 uptake have only considered extended periods of drought rather than an overall decrease in rainfall amount. We measured soil CH4 uptake from March 2010 to March 2012 after installing passive rainfall reduction systems to intercept approximately 40% of throughfall in a temperate broadleaf evergreen eucalypt forest in south-eastern Australia. Throughfall reduction caused an average reduction of 15.1 ± 6.4% (SE) in soil volumetric water content, a reduction of 19.8 ± 6.9% in soil water-filled pore space (%WFPS) and a 20.1 ± 6.8% increase in soil air-filled porosity. In response to these changes, soil CH4 uptake increased by 54.7 ± 19.3%. The increase in soil CH4 uptake could be explained by increased diffusivity in drier soils, whilst the activity of methanotrophs remained relatively unchanged. It is likely that soil CH4 uptake will increase if rainfall reduces in temperate broadleaf evergreen forests of Australia as a consequence of climate change.
Keywordssoil CH4 exchange soil moisture sensitivity soil temperature drought dry sclerophyll eucalypt forest throughfall reduction climate change south-eastern Australia
The study was supported by funding from the Terrestrial Ecosystem Research Network (TERN) Australian Supersite Network, the TERN OzFlux Network, the Australian Research Council (ARC) grants LE0882936 and DP120101735 and the Integrated Forest Ecosystem Research program funded by the Victorian Department of Environment, Land, Water & Planning. The authors specially thank the many internship students from the Institut Polytechnique LaSalle Beauvais, and Xin Kun and Julio Najera, who helped them with field data collection and in the laboratory, and Ian Gordon and Rachel Sore for their advice in statistical analyses.
- Butterbach-Bahl K, Breuer L, Gasche R, Willibald G, Papen H. 2002a. Exchange of trace gases between soils and the atmosphere in Scots pine forest ecosystems of the northeastern German lowlands 1. Fluxes of N2O, NO/NO2 and CH4 at forest sites with different N-deposition. For Ecol Manag 167:123–34.CrossRefGoogle Scholar
- Conrad R. 2007. Microbial ecology of methanogens and methanotrophs. In: Donald LS, Ed. Advances in agronomy. Boston: Academic Press. p 1–63.Google Scholar
- CSIRO. 2010. Climate variability and change in south-eastern Australia: a synthesis of findings from Phase 1 of the South Eastern Australian Climate Initiative (SEACI). Australia. p 36.Google Scholar
- CSIRO. 2012. Climate and water availability in south-eastern Australia: a synthesis of findings from Phase 2 of the South Eastern Australian Climate Initiative (SEACI). Australia. p 41.Google Scholar
- CSIRO, Australian Bureau of Meteorology. 2007. Climate change in Australia. Australia: CSIRO. p p148.Google Scholar
- CSIRO, Australian Bureau of Meteorology. 2012. State of the climate 2012. Australia: CSIRO. p p12.Google Scholar
- IPCC. 2013. The scientific basis. Contribution of Working Group I to the Fifth Assessment Report of the intergovernmental panel on climate change.In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Boschung J, Nauels S, Xia Y, Bex V, Midgley PM, Eds. Cambridge: Cambridge University Press. p 1535.Google Scholar
- Koster RD, Dirmeyer PA, Guo ZC, Bonan G, Chan E, Cox P, Gordon CT, Kanae S, Kowalczyk E, Lawrence D, Liu P, Lu CH, Malyshev S, McAvaney B, Mitchell K, Mocko D, Oki T, Oleson K, Pitman A, Sud YC, Taylor CM, Verseghy D, Vasic R, Xue YK, Yamada T, Team G. 2004. Regions of strong coupling between soil moisture and precipitation. Science 305:1138–40.CrossRefPubMedGoogle Scholar
- Loveday J, Commonwealth Bureau of Soils. 1973. Methods for analysis of irrigated soils. Farnham Royal: Commonwealth Agricultural Bureaux. p 208.Google Scholar
- Robinson N, Rees D, Reynard K, MacEwan R, Dahlhaus P, Imhof M, Boyle G, Baxter N. 2003. A land resource assessment of the Corangamite region. Bendigo: Primary Industries Research Victoria. p 121.Google Scholar
- The Commissioner for Environmental Sustainability. 2012. Foundation paper one; climate change victoria: the science, our people and our state of play. Melbourne: The Commissioner for Environmental Sustainability. p 144.Google Scholar