The 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fire
Extreme fire seasons characterised by very large ‘mega-fires’ have demonstrably increased area burnt across forested regions globally. However, the effect of extreme fire seasons on fire severity, a measure of fire impacts on ecosystems, remains unclear. Very large wildfires burnt an unprecedented a...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2021-01-01
|
| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/abeb9e |
| _version_ | 1797747831258218496 |
|---|---|
| author | Luke Collins Ross A Bradstock Hamish Clarke Michael F Clarke Rachael H Nolan Trent D Penman |
| author_facet | Luke Collins Ross A Bradstock Hamish Clarke Michael F Clarke Rachael H Nolan Trent D Penman |
| author_sort | Luke Collins |
| collection | DOAJ |
| description | Extreme fire seasons characterised by very large ‘mega-fires’ have demonstrably increased area burnt across forested regions globally. However, the effect of extreme fire seasons on fire severity, a measure of fire impacts on ecosystems, remains unclear. Very large wildfires burnt an unprecedented area of temperate forest, woodland and shrubland across south-eastern Australia in 2019/2020, providing an opportunity to examine the impact of extreme fires on fire severity patterns. We developed an atlas of wildfire severity across south-eastern Australia between 1988 and 2020 to test (a) whether the 2019/2020 fire season was more severe than previous fire seasons, and (b) if the proportion of high-severity fire within the burn extent (HSp) increases with wildfire size and annual area burnt. We demonstrate that the 2019/2020 wildfires in south-eastern Australia were generally greater in extent but not proportionally more severe than previous fires, owing to constant scaling between HSp and annual fire extent across the dominant dry-forest communities. However, HSp did increase with increasing annual fire extent across wet-forests and the less-common rainforest and woodland communities. The absolute area of high-severity fire in 2019/2020 (∼1.8 M ha) was larger than previously seen, accounting for ∼44% of the area burnt by high-severity fire over the past 33 years. Our results demonstrate that extreme fire seasons are a rare but defining feature of fire regimes across forested regions, owing to the disproportionate influence of mega-fires on area burnt. |
| first_indexed | 2024-03-12T15:56:15Z |
| format | Article |
| id | doaj.art-f375696d43674d3ba96eedf199e8f719 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:56:15Z |
| publishDate | 2021-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-f375696d43674d3ba96eedf199e8f7192023-08-09T14:55:37ZengIOP PublishingEnvironmental Research Letters1748-93262021-01-0116404402910.1088/1748-9326/abeb9eThe 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fireLuke Collins0https://orcid.org/0000-0001-8059-0925Ross A Bradstock1https://orcid.org/0000-0002-6904-2394Hamish Clarke2https://orcid.org/0000-0002-8747-3729Michael F Clarke3https://orcid.org/0000-0003-1138-2908Rachael H Nolan4https://orcid.org/0000-0001-9277-5142Trent D Penman5https://orcid.org/0000-0002-5203-9818School of Ecosystem and Forest Sciences, University of Melbourne , Creswick, Victoria 3363, Australia; Department of Ecology, Environment and Evolution, La Trobe University , Bundoora, Victoria 3086, Australia; Arthur Rylah Institute for Environmental Research , Department of Environment, Land, Water and Planning, PO Box 137, Heidelberg, Victoria 3084, Australia; Research Centre for Future Landscapes, La Trobe University , Bundoora, Victoria 3086, AustraliaCentre for Environmental Risk Management of Bushfire, University of Wollongong , Wollongong, NSW 2522, Australia; NSW Bushfire Risk Management Research Hub , Wollongong, NSW 2522, AustraliaCentre for Environmental Risk Management of Bushfire, University of Wollongong , Wollongong, NSW 2522, Australia; NSW Bushfire Risk Management Research Hub , Wollongong, NSW 2522, AustraliaDepartment of Ecology, Environment and Evolution, La Trobe University , Bundoora, Victoria 3086, Australia; Research Centre for Future Landscapes, La Trobe University , Bundoora, Victoria 3086, AustraliaNSW Bushfire Risk Management Research Hub , Wollongong, NSW 2522, Australia; Hawkesbury Institute for the Environment, Western Sydney University , Locked Bag 1797, Penrith, NSW 2751, AustraliaSchool of Ecosystem and Forest Sciences, University of Melbourne , Creswick, Victoria 3363, AustraliaExtreme fire seasons characterised by very large ‘mega-fires’ have demonstrably increased area burnt across forested regions globally. However, the effect of extreme fire seasons on fire severity, a measure of fire impacts on ecosystems, remains unclear. Very large wildfires burnt an unprecedented area of temperate forest, woodland and shrubland across south-eastern Australia in 2019/2020, providing an opportunity to examine the impact of extreme fires on fire severity patterns. We developed an atlas of wildfire severity across south-eastern Australia between 1988 and 2020 to test (a) whether the 2019/2020 fire season was more severe than previous fire seasons, and (b) if the proportion of high-severity fire within the burn extent (HSp) increases with wildfire size and annual area burnt. We demonstrate that the 2019/2020 wildfires in south-eastern Australia were generally greater in extent but not proportionally more severe than previous fires, owing to constant scaling between HSp and annual fire extent across the dominant dry-forest communities. However, HSp did increase with increasing annual fire extent across wet-forests and the less-common rainforest and woodland communities. The absolute area of high-severity fire in 2019/2020 (∼1.8 M ha) was larger than previously seen, accounting for ∼44% of the area burnt by high-severity fire over the past 33 years. Our results demonstrate that extreme fire seasons are a rare but defining feature of fire regimes across forested regions, owing to the disproportionate influence of mega-fires on area burnt.https://doi.org/10.1088/1748-9326/abeb9efire regimesfire severitymega-firestemperate forest |
| spellingShingle | Luke Collins Ross A Bradstock Hamish Clarke Michael F Clarke Rachael H Nolan Trent D Penman The 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fire Environmental Research Letters fire regimes fire severity mega-fires temperate forest |
| title | The 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fire |
| title_full | The 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fire |
| title_fullStr | The 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fire |
| title_full_unstemmed | The 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fire |
| title_short | The 2019/2020 mega-fires exposed Australian ecosystems to an unprecedented extent of high-severity fire |
| title_sort | 2019 2020 mega fires exposed australian ecosystems to an unprecedented extent of high severity fire |
| topic | fire regimes fire severity mega-fires temperate forest |
| url | https://doi.org/10.1088/1748-9326/abeb9e |
| work_keys_str_mv | AT lukecollins the20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT rossabradstock the20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT hamishclarke the20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT michaelfclarke the20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT rachaelhnolan the20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT trentdpenman the20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT lukecollins 20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT rossabradstock 20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT hamishclarke 20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT michaelfclarke 20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT rachaelhnolan 20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire AT trentdpenman 20192020megafiresexposedaustralianecosystemstoanunprecedentedextentofhighseverityfire |