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

Research output: Contribution to journalArticle

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.

Details

Authors
  • Daniel B. Metcalfe
  • Wanderley Rocha
  • Jennifer K. Balch
  • Paulo M. Brando
  • Christopher E. Doughty
  • Yadvinder Malhi
Organisations
External organisations
  • Umeå University
  • Amazon Environmental Research Institute (IPAM)
  • University of Colorado
  • Northern Arizona University
  • University of Oxford
  • Woods Hole Research Center
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Climate Research

Keywords

  • Amazon tropical rain forest, Burn experiment, Carbon dioxide, Climate change, Fire, Mycorrhizae, Soil respiration partitioning
Original languageEnglish
Pages (from-to)3629-3641
JournalGlobal Change Biology
Volume24
Issue number8
Early online date2018 Jan 1
Publication statusPublished - 2018 Aug
Publication categoryResearch
Peer-reviewedYes