Oecologia

, Volume 172, Issue 2, pp 539–550

Provisioning of bioavailable carbon between the wet and dry phases in a semi-arid floodplain

  • Darren S. Baldwin
  • Gavin N. Rees
  • Jessica S. Wilson
  • Matthew J. Colloff
  • Kerry L. Whitworth
  • Tara L. Pitman
  • Todd A. Wallace
Ecosystem ecology - Original research

DOI: 10.1007/s00442-012-2512-8

Cite this article as:
Baldwin, D.S., Rees, G.N., Wilson, J.S. et al. Oecologia (2013) 172: 539. doi:10.1007/s00442-012-2512-8

Abstract

Ecosystem functioning on arid and semi-arid floodplains may be described by two alternate traditional paradigms. The pulse-reserve model suggests that rainfall is the main driver of plant growth and subsequent carbon and energy reserve formation in the soil of arid and semi-arid regions. The flood pulse concept suggests that periodic flooding facilitates the two-way transfer of materials between a river and its adjacent floodplain, but focuses mainly on the period when the floodplain is inundated. We compared the effects of both rainfall and flooding on soil moisture and carbon in a semi-arid floodplain to determine the relative importance of each for soil moisture recharge and the generation of a bioavailable organic carbon reserve that can potentially be utilised during the dry phase. Flooding, not rainfall, made a substantial contribution to moisture in the soil profile. Furthermore, the growth of aquatic macrophytes during the wet phase produced at least an order of magnitude more organic material than rainfall-induced pulse-reserve responses during the dry phase, and remained as recognizable soil carbon for years following flood recession. These observations have led us to extend existing paradigms to encompass the reciprocal provisioning of carbon between the wet and dry phases on the floodplain, whereby, in addition to carbon fixed during the dry phase being important for driving biogeochemical transformations upon return of the next wet phase, aquatic macrophyte carbon fixed during the wet phase is recognized as an important source of energy for the dry phase. Reciprocal provisioning presents a conceptual framework on which to formulate questions about the resistance and ecosystem resilience of arid and semi-arid floodplains in the face of threats like climate change and alterations to flood regimes.

Keywords

Pulse-reserve Flood pulse concept Soil carbon Ecosystem resilience Rainfall 

Supplementary material

442_2012_2512_MOESM1_ESM.doc (13 mb)
Supplementary material 1 (DOC 13317 kb)

Copyright information

© Her Majesty the Queen in Rights of Australia 2012

Authors and Affiliations

  • Darren S. Baldwin
    • 1
  • Gavin N. Rees
    • 1
  • Jessica S. Wilson
    • 2
  • Matthew J. Colloff
    • 3
  • Kerry L. Whitworth
    • 2
  • Tara L. Pitman
    • 2
  • Todd A. Wallace
    • 1
    • 4
  1. 1.Murray-Darling Freshwater Research Centre and CSIRO Land and WaterLa Trobe UniversityWodongaAustralia
  2. 2.Murray-Darling Freshwater Research CentreLa Trobe UniversityWodongaAustralia
  3. 3.CSIRO Ecosystem SciencesCanberraAustralia
  4. 4.Water Research CentreThe University of AdelaideAdelaideAustralia

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