The Importance of Termites to the CH4 Balance of a Tropical Savanna Woodland of Northern Australia
- 363 Downloads
Termites produce methane (CH4) as a by-product of microbial metabolism of food in their hindguts, and are one of the most uncertain components of the regional and global CH4 exchange estimates. This study was conducted at Howard Springs near Darwin, and presents the first estimate of CH4 emissions from termites based on replicated in situ seasonal flux measurements in Australian savannas. Using measured fluxes of CH4 between termite mounds and the atmosphere, and between soil and the atmosphere across seasons we determined net CH4 flux within a tropical savanna woodland of northern Australia. By accounting for both mound-building and subterranean termite colony types, and estimating the contribution from tree-dwelling colonies it was calculated that termites were a CH4 source of +0.24 kg CH4-C ha−1 y−1 and soils were a CH4 sink of −1.14 kg CH4-C ha−1 y−1. Termites offset 21% of CH4 consumed by soil resulting in net sink strength of −0.90 kg CH4-C ha−1 y−1 for these savannas. For Microcerotermes nervosus (Hill), the most abundant mound-building termite species at this site, mound basal area explained 48% of the variation in mound CH4 flux. CH4 emissions from termites offset 0.1% of the net biome productivity (NBP) and CH4 consumption by soil adds 0.5% to the NBP of these tropical savannas at Howard Springs.
Key wordsmethane termite mounds soil methane oxidation subterranean termites hypogeal termites Microcerotermes nervosus
This research was supported by the Australian Research Council, Linkage project grant LP0774812. Jamali was supported by an AusAID postgraduate scholarship. We are thankful to Gus Wanganeen from CSIRO Ecosystem Sciences, Darwin for identifying the termite species. We are thankful to Dr Alan Anderson from CSIRO Ecosystem Sciences, Darwin and Dr Brett Murphy from the University of Tasmania for reviewing an earlier draft of this manuscript. In Charles Darwin National Park research was carried out through permit number 29227 of the Northern Territory Government, Australia.
- Bignell DE, Eggleton P, Nunes L, Thomas KL. 1997. Termites as mediators of forest carbon fluxes in tropical forests: budgets for carbon dioxide and methane emissions. In: Watt AD, Stork NE, Hunter MD, Eds. Forests and insects. London: Chapman and Hall. p 109–34.Google Scholar
- Brümmer C, Papen H, Wassmann R, Bruggemann N. 2009. Fluxes of CH4 and CO2 from soil and termite mounds in south Sudanian savanna of Burkina Faso (West Africa). Global Biogeochem Cycles 23, GB1001.Google Scholar
- Bureau of Meteorology, 2009. Government of Australia, www.bom.gov.au.
- Cook GD, Meyer CP. 2009. Fires, fuels and greenhouse gases. In: Russell-Smith J, Whitehead P, Cooke P, Eds. Culture ecology and economy of fire management in North Australian savannas. Melbourne: CSIRO Publishing. p 313–28.Google Scholar
- Denman KL, Brasseur G. 2007. Couplings between changes in the climate system and biogeochemistry. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL, Eds. Climate change 2007: the physical science basis. Contribution of working group I into the fourth assessment report of the intergovernmental panel on climate change. Cambridge, New York (NY): Cambridge University Press. p 499–588.Google Scholar
- Dutaur L, Verchot LV. 2007. A global inventory of the soil CH4 sink. Global Biogeochem Cycles 21:GB4013. doi: 10.1029/2006GB002734.
- Forster P, Ramaswamy V, Artaxo P, Berntsen T, Betts R, Fahey DW, Haywood J, Lean J, Lowe DC, Myhre G, Nganga J, Prinn R, Raga G, Schulz M, Van Dorland R. 2007. Changes in atmospheric constituents and in radiative forcing. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL, Eds. Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge, New York (NY): Cambridge University Press. p 129–234.Google Scholar
- Fox ID, Neldner VJWWG, Bannink PJ. 2001. The vegetation of the Australian tropical savannas. Brisbane: Environmental Protection Agency, Queensland Government.Google Scholar
- IPCC. 2007. Climate change 2007: the physical science basis. Cambridge: Cambridge University Press.Google Scholar
- Jamali H, Livesley SJ, Dawes TZ, Cook GD, Hutley LB, Arndt SK. 2011. Diurnal and seasonal variations in CH4 flux from termite mounds in tropical savannas of the Northern Territory, Australia. J Agric For Meteorol (in press).Google Scholar
- Lavelle P, Bignell D, Lepage M, Wolters V, Roger P, Ineson P, Heal OW, Dhillion S. 1997. Soil function in a changing world: the role of invertebrate ecosystem engineers. Eur J Soil Biol 33:159–93.Google Scholar
- Lepage M. 1982. Foraging of Macrotermes spp. (Isoptera: Macrotermitinae) in the tropics. In: Jaisson P, Ed. Social insects. Paris: Universite’ de Paris-Norad. p 206–18.Google Scholar
- Rouland C, Brauman A, Labat M, Lepage M. 1993. Nutritional factors affecting methane emissions from termites. Amsterdam: Pergamon-Elsevier Science Ltd. pp 617–22.Google Scholar
- Sugimoto A, Bignell DE, McDonald JA. 2000. Global impact of termites on the carbon cycle and atmospheric trace gases. In: Abe T, Bignell DE, Higashi M, Eds. Termites: evolution sociality, symbiosis, ecology. Dordrecht: Kluwer Academic Publishers. p 409–35.Google Scholar
- Watson JAL, Abbey HM. 1993. Atlas of Australian termites. Australia: CSIRO.Google Scholar
- Wood TG, Sands WA. 1978. The role of termites in ecosystems. In: Brian MV, Ed. Production ecology of ants and termites. Cambridge: Cambridge University Press. p 245–92.Google Scholar