Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions
North Australian tropical savanna accounts for 12% of the world’s total savanna land cover. Accordingly, understanding processes that govern carbon, water and energy exchange within this biome is critical to global carbon and water budgeting. Climate and disturbances drive ecosystem carbon dynamics....
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2013-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/8/4/045023 |
| _version_ | 1797748053719908352 |
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| author | L B Hutley B J Evans J Beringer G D Cook S W Maier E Razon |
| author_facet | L B Hutley B J Evans J Beringer G D Cook S W Maier E Razon |
| author_sort | L B Hutley |
| collection | DOAJ |
| description | North Australian tropical savanna accounts for 12% of the world’s total savanna land cover. Accordingly, understanding processes that govern carbon, water and energy exchange within this biome is critical to global carbon and water budgeting. Climate and disturbances drive ecosystem carbon dynamics. Savanna ecosystems of the coastal and sub-coastal of north Australia experience a unique combination of climatic extremes and are in a state of near constant disturbance from fire events (1 in 3 years), storms resulting in windthrow (1 in 5–10 years) and mega-cyclones (1 in 500–1000 years). Critically, these disturbances occur over large areas creating a spatial and temporal mosaic of carbon sources and sinks. We quantify the impact on gross primary productivity (GPP) and fire occurrence from a tropical mega-cyclone, tropical Cyclone Monica (TC Monica), which affected 10 400 km ^2 of savanna across north Australia, resulting in the mortality and severe structural damage to ∼140 million trees. We estimate a net carbon equivalent emission of 43 Tg of CO _2 -e using the moderate resolution imaging spectroradiometer (MODIS) GPP (MOD17A2) to quantify spatial and temporal patterns pre- and post-TC Monica. GPP was suppressed for four years after the event, equivalent to a loss of GPP of 0.5 Tg C over this period. On-ground fuel loads were estimated to potentially release 51.2 Mt CO _2 -e, equivalent to ∼10% of Australia’s accountable greenhouse gas emissions. We present a simple carbon balance to examine the relative importance of frequency versus impact for a number of key disturbance processes such as fire, termite consumption and intense but infrequent mega-cyclones. Our estimates suggested that fire and termite consumption had a larger impact on Net Biome Productivity than infrequent mega-cyclones. We demonstrate the importance of understanding how climate variability and disturbance impacts savanna dynamics in the context of the increasing interest in using savanna landscapes for enhanced carbon sinks in emission offset schemes. |
| first_indexed | 2024-03-12T16:00:26Z |
| format | Article |
| id | doaj.art-405abc665ef3475ba329a9b8ff4eafc2 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:00:26Z |
| publishDate | 2013-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-405abc665ef3475ba329a9b8ff4eafc22023-08-09T14:39:53ZengIOP PublishingEnvironmental Research Letters1748-93262013-01-018404502310.1088/1748-9326/8/4/045023Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissionsL B Hutley0B J Evans1J Beringer2G D Cook3S W Maier4E Razon5School of Environment, Research Institute for the Environment and Livelihoods, Charles Darwin University , NT, 0909, AustraliaDepartment of Biological Sciences, Macquarie University , North Ryde, New South Wales, 2113, AustraliaSchool of Geography and Environmental Science, Monash University , Victoria, 3800, Australia; School of Earth and Environment, University of Western Australia , WA, 6009, AustraliaCSIRO Ecosystem Sciences , PMB 44 Winnellie NT, 0822, AustraliaSchool of Environment, Research Institute for the Environment and Livelihoods, Charles Darwin University , NT, 0909, AustraliaCSIRO Ecosystem Sciences , PMB 44 Winnellie NT, 0822, AustraliaNorth Australian tropical savanna accounts for 12% of the world’s total savanna land cover. Accordingly, understanding processes that govern carbon, water and energy exchange within this biome is critical to global carbon and water budgeting. Climate and disturbances drive ecosystem carbon dynamics. Savanna ecosystems of the coastal and sub-coastal of north Australia experience a unique combination of climatic extremes and are in a state of near constant disturbance from fire events (1 in 3 years), storms resulting in windthrow (1 in 5–10 years) and mega-cyclones (1 in 500–1000 years). Critically, these disturbances occur over large areas creating a spatial and temporal mosaic of carbon sources and sinks. We quantify the impact on gross primary productivity (GPP) and fire occurrence from a tropical mega-cyclone, tropical Cyclone Monica (TC Monica), which affected 10 400 km ^2 of savanna across north Australia, resulting in the mortality and severe structural damage to ∼140 million trees. We estimate a net carbon equivalent emission of 43 Tg of CO _2 -e using the moderate resolution imaging spectroradiometer (MODIS) GPP (MOD17A2) to quantify spatial and temporal patterns pre- and post-TC Monica. GPP was suppressed for four years after the event, equivalent to a loss of GPP of 0.5 Tg C over this period. On-ground fuel loads were estimated to potentially release 51.2 Mt CO _2 -e, equivalent to ∼10% of Australia’s accountable greenhouse gas emissions. We present a simple carbon balance to examine the relative importance of frequency versus impact for a number of key disturbance processes such as fire, termite consumption and intense but infrequent mega-cyclones. Our estimates suggested that fire and termite consumption had a larger impact on Net Biome Productivity than infrequent mega-cyclones. We demonstrate the importance of understanding how climate variability and disturbance impacts savanna dynamics in the context of the increasing interest in using savanna landscapes for enhanced carbon sinks in emission offset schemes.https://doi.org/10.1088/1748-9326/8/4/045023Cyclone MonicaMODISGPPdisturbancefiretermites |
| spellingShingle | L B Hutley B J Evans J Beringer G D Cook S W Maier E Razon Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions Environmental Research Letters Cyclone Monica MODIS GPP disturbance fire termites |
| title | Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions |
| title_full | Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions |
| title_fullStr | Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions |
| title_full_unstemmed | Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions |
| title_short | Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions |
| title_sort | impacts of an extreme cyclone event on landscape scale savanna fire productivity and greenhouse gas emissions |
| topic | Cyclone Monica MODIS GPP disturbance fire termites |
| url | https://doi.org/10.1088/1748-9326/8/4/045023 |
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