Seasonal litter decomposition and accumulation in north Australian savanna

Cameron Yates; Jay Evans; Jeremy Russell-Smith

doi:10.1071/WF24053

RESEARCH ARTICLE (Open Access)

Previous Contents Vol 33(8)

Seasonal litter decomposition and accumulation in north Australian savanna

Cameron Yates ^A ^* , Jay Evans ^A and Jeremy Russell-Smith ^A

+ Author Affiliations

- Author Affiliations

^A Darwin Centre for Bushfire Research, Research Institute or Environment and Livelihoods, Charles Darwin University, Darwin, NT 0909, Australia.

^* Correspondence to: cameron.yates@cdu.edu.au

International Journal of Wildland Fire 33, WF24053 https://doi.org/10.1071/WF24053

Submitted: 20 March 2024 Accepted: 28 June 2024 Published: 26 July 2024

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of IAWF. This is an open access article distributed under the Creative Commons Attribution 4.0 International License (CC BY)

Abstract

Background

Calculating greenhouse gas emissions from fires relies on estimation of available fuels at time of burn. Fuel accumulation and decomposition occur throughout the year, with seasonality of decomposition poorly researched in monsoonal Australia.

Aims

We investigate the decomposition and accumulation of litter fuels (leaves, twigs), and coarse woody debris (CWD >6 mm–<5 cm diameter) across a full monsoonal cycle.

Methods

The study was undertaken at three sites in long unburned (10 years+) eucalypts-dominated mesic savanna woodland. For measuring decomposition, twelve 50 g samples of leaves and twigs were placed in situ on the soil surface, with one sample removed and dried each month; one sample of CWD was tested after 12 months. Fine fuel accumulation was recorded monthly.

Key results

Significant statistical relationships were observed between soil moisture and leaf decomposition. Across the study period 66% of leaves, 35% of twig, and 27.2% of CWD decomposed. Fine fuel accumulation was consistent with previous studies and peaking in August. Combining monthly rates of accumulation and decomposition, net fine fuel loads were observed to be much greater late in the dry season.

Implications

The present study provides enhanced fine fuel load calculations by including seasonality of decomposition which allows for better estimates of emissions from savanna fires.

Keywords: coarse woody debris, EDS (early dry season), eucalyptus - dominated mesic savanna, fine fuels, fire emissions, fuel loads, LDS (late dry season), monsoonal Australia.

References

Chen X, Eamus D, Hutley LB (2002) Seasonal patterns of soil carbon dioxide efflux from a wet–dry tropical savanna of northern Australia. Australian Journal of Botany 50, 43-52.
| Crossref | Google Scholar |

CoA (Commonwealth of Australia) (2013) Carbon Credits (Carbon Farming Initiative) Reduction of Greenhouse Gas Emissions through Early Dry Season Savanna Burning—1.1) Methodology Determination 2013. Available at http://www.comlaw.gov.au/Series/F2013L01165

CoA (Commonwealth of Australia) (2015) Carbon Credits (Carbon Farming Initiative—Emissions Abatement through Savanna Fire Management) Methodology Determination 2015. (ComLaw, Australian Govt.: Canberra, ACT). Available at http://www.comlaw.gov.au/Details/F2015L00344

CoA (Commonwealth of Australia) (2018) Carbon Credits (Carbon Farming Initiative—Savanna Fire Management—Emissions Avoidance) Methodology Determination 2018. (Dept Environment and Energy, Australian Government: Canberra, ACT). Available at https://www.legislation.gov.au/F2018L00560/latest/text

Cook GD (2003) Fuel dynamics, nutrients and atmospheric chemistry. In ‘Fire in tropical savannas: the Kapalga experiment’. (Eds AN Andersen, GD Cook, RJ Williams) pp. 47–58. (Springer: New York, NY, USA)

Cook GD, Meyer CPM (2017) Seasonal variation in fine fuel accumulation in savannas. Technical Report. (CSIRO: Australia)

Cuff N, Brocklehurst P (2015) Leaf and coarse fuel accumulation relationships with vegetation attributes in evergreen tropical eucalypt savanna. In ‘Carbon accounting and savanna fire management’. (Eds BP Murphy, AC Edwards, CP Meyer, J Russell-Smith) pp. 133–168. (CSIRO Publishing: Melbourne, Australia)

Davies AB, van Rensburg BJ, Eggleton P, Parr CL (2013) Interactive effects of fire, rainfall, and litter quality on decomposition in savannas: frequent fire leads to contrasting effects. Ecosystems 16, 866-880.
| Crossref | Google Scholar |

Department of the Environment and Energy – Australian Government (2019) Report - Understanding Savann Fire Management Methods in the Emissions Reduction Fund. (Commonwealth of Australia)

Erin EJ, Kennedy MC, Ren J, Johnson MC, Smith AMS (2022) Missing climate feedbacks in fire models: limitations and uncertainties in fuel loadings and the role of decomposition in fine fuel accumulation. Journal of Advances in Modeling Earth Systems 14(3), e2021MS002818.
| Crossref | Google Scholar |

Furniss PR, Ferrar P, Morris JW, Bezuidenhout JJ (1982) A model of savanna litter decomposition. Ecological Modelling 17(1), 33-51.
| Crossref | Google Scholar |

Giglio L, Boschetti L, Roy DP, Humber ML, Justice CO (2018) The Collection 6 MODIS burned area mapping algorithm and product. Remote Sensing of Environment 217, 72-85.
| Crossref | Google Scholar | PubMed |

Gould JS, McCaw WL, Cheney NP (2011) Quantifying fine fuel dynamics and structure in dry eucalypt forest (Eucalyptus marginata) in Western Australia for fire management. Forest Ecology and Management 262(3), 531-546 ISSN 0378-112.
| Crossref | Google Scholar |

Hanan EJ, Kennedy MC, Ren J, Johnson MC, Smith AM (2022) Missing climate feedbacks in fire models: limitations and uncertainties in fuel loadings and the role of decomposition in fine fuel accumulation. Journal of Advances in Modeling Earth Systems 14(3), e2021MS002818.
| Crossref | Google Scholar |

Harris RMB, Remenyi TA, Williamson GJ, Bindoff NL, Bowman DMJS (2016) Climate–vegetation–fire interactions and feedbacks: trivial detail or major barrier to projecting the future of the Earth system? WIREs Climate Change 7, 910-931.
| Crossref | Google Scholar |

Hopkins JR, Huffman JM, Platt WJ, Sikes BA (2020) Frequent fire slows microbial decomposition of newly deposited fine fuels in a pyrophilic ecosystem. Oecologia 193, 631-643.
| Crossref | Google Scholar | PubMed |

Lehmann CER, Anderson TM, Sankaran M, Higgins SI, Archibald S, Hoffmann WA, Hanan NP, Williams RJ, Fensham R, Felfili J, Hutley L, Ratnam J, San Jose J, Montes R, Franklin DC, Russell-Smith J, Ryan C, Durigan G, Hiernaux P, Haidar R, Bowman DMJS, Bond WJ (2014) Savanna vegetation-fire-climate relationships differ between continents. Science 343, 548-552.
| Crossref | Google Scholar |

Meyer CP, Cook GD (2015) Biomass combustion and emission processes in the northern Australian savannas. In ‘Carbon accounting and savanna fire management’. (Eds Murphy B, Russell-Smith J, Edwards A, Meyer CP) pp. 185–217. (CSIRO Publishing: Melbourne, Australia)

Moise A, Abbs D, Bhend J, Chiew F, Church J, Ekström M, Kirono D, Lenton A, Lucas C, McInnes K, Monselesan D, Mpelasoka F, Webb L, Whetton P (2015) Monsoonal North Cluster Report, Climate Change in Australia Projections for Australia’s Natural Resource Management Regions: Cluster Reports. (Eds M Ekström, P Whetton, C Gerbing, M Grose, L Webb, J Risbey) (CSIRO and Bureau of Meteorology: Australia)

Moura LC, Scariot AO, Schmidt IB, Beatty R, Russell-Smith J (2019) The legacy of colonial fire management policies on traditional livelihoods and ecological sustainability in savannas: impacts, consequences, new directions. Journal of Environmental Management 232, 600-606.
| Crossref | Google Scholar | PubMed |

Murphy B, Russell-Smith J, Edwards A, Meyer CP (Eds) (2015) ‘Carbon accounting and savanna fire management.’ (CSIRO Publishing: Melbourne, Australia)

Murphy B, Whitehead PJ, Evans J, Yates CP, Edwards AC, MacDermott HJ, Lynch DC, Russell‐Smith J (2023) Using a demographic model to project the long‐term effects of fire management on tree biomass in Australian savannas. Ecological Monographs 93(2), e1564.
| Crossref | Google Scholar |

Ngatia LW, Reddy KR, Nair PKR, Pringle RM, Palmer TM, Turner BT (2014) Seasonal patterns in decomposition and nutrient release from East African savanna grasses grown under contrasting nutrient conditions. Agriculture, Ecosystems & Environment 188, 12-19.
| Crossref | Google Scholar |

Olson JS (1963) Energy storage and the balance of producers and decomposers in ecological systems. Ecology 44, 322-334.
| Crossref | Google Scholar |

Pyne SJ (1997) ‘World fire: the culture of fire on Earth.’ (University of Washington Press: Seattle and London)

Rossiter-Rachor NA, Setterfield SA, Douglas MM, Hutley LB, Cook GD (2008) Andropogon gayanus (gamba grass) invasion increases fire-mediated nitrogen losses in the tropical savannas of northern Australia. Ecosystems 11, 77-88.
| Crossref | Google Scholar |

Rossiter-Rachor NA, Setterfield SA, Hutley LB, McMaster D, Schmidt S, Douglas MM (2017) Invasive Andropogon gayanus (Gamba grass) alters litter decomposition and nitrogen fluxes in an Australian tropical savanna. Scientific Reports 7(1), 11705.
| Crossref | Google Scholar | PubMed |

Russell-Smith J, Yates C, Edwards A, Allan GE, Cook GD, Cooke P, Craig R, Heath B, Smith R (2003) Contemporary fire regimes of northern Australia, 1997–2001: change since Aboriginal occupancy, challenges for sustainable management. International Journal of Wildland Fire 12, 283-297.
| Crossref | Google Scholar |

Russell-Smith J, Yates C, Lynch B (2006) Fire regimes and soil erosion in north Australian hilly savannas. International Journal of Wildland Fire 15, 551-556.
| Crossref | Google Scholar |

Russell-Smith J, Murphy BP, Meyer CPM, Cook GD, Maier S, Edwards AC, Schatz J, Brocklehurst P (2009) Improving estimates of savanna burning emissions for greenhouse accounting in northern Australia: limitations, challenges, applications. International Journal of Wildland Fire 18(1), 1-18.
| Crossref | Google Scholar |

Scholes RJ, Archer SR (1997) Tree-grass interactions in savannas. Annual Review of Ecology and Systematics 28, 517-544.
| Crossref | Google Scholar |

Townsend SA, Douglas MM (2004) The effect of a wildfire on stream water quality and catchment water yield in a tropical savanna excluded from fire for 10 years (Kakadu National Park, North Australia). Water Research 38(13), 3051-3058.
| Crossref | Google Scholar | PubMed |

van der Werf GR, Randerson JT, Giglio L, van Leeuwen TT, Chen Y, Rogers BM, Mu M, van Marle MJE, Morton DC, Collatz GJ, Yokelson RJ, Kasibhatla PS (2017) Global fire emissions estimates during 1997–2016. Earth System Science Data 9, 697-720.
| Crossref | Google Scholar |

Vernooij R, Eames T, Russell-Smith J, Yates C, Beatty R, Evans J, Edwards A (2023) Dynamic savanna burning emission factors based on satellite data using a machine learning approach. EGUsphere 2023, 1-31.
| Crossref | Google Scholar |

Yates CP, Edwards AC, Russell-Smith J (2008) Big fires and their ecological impacts in Australian savannas: size and frequency matters. International Journal of Wildland Fire 17, 768-781.
| Crossref | Google Scholar |

Yates C, MacDermott H, Evans J, Murphy BP, Russell-Smith J (2020) Seasonal fine fuel and coarse woody debris dynamics in north Australian savannas. International Journal of Wildland Fire 29, 1109-1119.
| Crossref | Google Scholar |

Yibarbuk D, Whitehead PJ, Russell‐Smith J, Jackson D, Godjuwa C, Fisher A, Cooke P, Choquenot D, Bowman D (2001) Fire ecology and Aboriginal land management in central Arnhem Land, northern Australia: a tradition of ecosystem management. Journal of Biogeography 28(3), 325-343.
| Crossref | Google Scholar |

Ziembicki MR, Woinarski JCZ, Webb JK, Vanderduys E, Tuft K, Smith J, Ritchie EG (2015) Stemming the tide: progress towards resolving the causes of decline and implementing management responses for the disappearing mammal fauna of northern Australia. Therya 6(1), 169-225.
| Crossref | Google Scholar |