Impacts of fire on sources of soil CO2 efflux in a dry Amazon rain forest

Daniel B. Metcalfe, Wanderley Rocha, Jennifer K. Balch, Paulo M. Brando, Christopher E. Doughty, Yadvinder Malhi

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Fire at the dry southern margin of the Amazon rainforest could have major consequences for regional soil carbon (C) storage and ecosystem carbon dioxide (CO2) emissions, but relatively little information exists about impacts of fire on soil C cycling within this sensitive ecotone. We measured CO2 effluxes from different soil components (ground surface litter, roots, mycorrhizae, soil organic matter) at a large-scale burn experiment designed to simulate a severe but realistic potential future scenario for the region (Fire plot) in Mato Grosso, Brazil, over 1 year, and compared these measurements to replicated data from a nearby, unmodified Control plot. After four burns over 5 years, soil CO2 efflux (Rs) was ~5.5 t C ha−1 year−1 lower on the Fire plot compared to the Control. Most of the Fire plot Rs reduction was specifically due to lower ground surface litter and root respiration. Mycorrhizal respiration on both plots was around ~20% of Rs. Soil surface temperature appeared to be more important than moisture as a driver of seasonal patterns in Rs at the site. Regular fire events decreased the seasonality of Rs at the study site, due to apparent differences in environmental sensitivities among biotic and abiotic soil components. These findings may contribute toward improved predictions of the amount and temporal pattern of C emissions across the large areas of tropical forest facing increasing fire disturbances associated with climate change and human activities.

Original languageEnglish (US)
Pages (from-to)3629-3641
Number of pages13
JournalGlobal change biology
Volume24
Issue number8
DOIs
StatePublished - Aug 2018

Keywords

  • Amazon tropical rain forest
  • burn experiment
  • carbon dioxide
  • climate change
  • fire
  • mycorrhizae
  • soil respiration partitioning

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

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