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Biodiversity Impacts of Prescribed Burning in SW Australia

Study on prescribed burning in SW Australia, its impacts on landscapes and species, and the challenge of species resilience in a changing climate.

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Biodiversity Impacts of Prescribed Burning in SW Australia

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  1. Biodiversity and Ecological Impacts of Prescribed Burning in the South-west Australian Biodiversity HotspotDon Bradshaw and Kingsley DixonAdapted from: Bradshaw et al. (2018) J of Wildands Fire. doi.org/10.1071/WF18067

  2. The Review FoundOne size does not fit all • The five mediterranean regions showed PB of uncertain or limited value including rare species protection. For South-west WA • Target driven burning at current scales is a major impact on SW landscapes and species • Frequency and aseasonality of PB will challenge species resilience – lack of an evolutionary framework • Long unburnt sites are essential for a suite of animal species • A rapidly drying climate will require longer inter-fire recovery periods • Protective value of PB is uncertain

  3. “We are the kings of extinction” Leslie Shultz (Njadju) • In 200 years Australia has been responsible for more mammal extinctions than any other country. • Australia is the fourth worst contry for extinctions. • 35 per cent of global mammal extinctions since 1500 are Australian. • >500 threatened animals and 1300 plant species are federally listed. • Australia is one of seven countries responsible for half of the globe’s biodiversity loss. Endemism: 82% mammals, 45% terrestrial birds, 85% flowering plants, 89% reptiles and 93% frogs.

  4. WesternAustralia is more biodiverse than 98% of other countries Kwongkan 10 meters x 10 meters = 110 flowering plant species

  5. A 3.5km B 3.5-11km C >11km

  6. Prescribed burning 2 May 2019

  7. 1918 CE Lane Poole legislated to protect forests from ‘devastation within a generation’ 1918 Charles Lane-Poole advocated for protection of forests from fire to protect the timber and the aesthetic. Kessell followed and commenced systematic prescribed burning

  8. Historical perceptions of imposed fire Victorian Royal Commission into the 1939 Fires. Nos. 2: 6912

  9. SW Australia: Largescale, high frequency and aseasonal 200,000 ha pa Fuel age <6 years* Area excludes wildfire and PB escapes? Independent of fuel load • Subject to burning 45% of area, could be up to 11y • between burns

  10. A world view "Prescribed fires can sometimes be used to replace the original role of wildfires” (but not always) Evolutionary scale Pausas and Keeley (2019) Front Ecol Environ 17(5) doi:10.1002/fee.2044

  11. ImpactsKings Park’s ‘banksia’ woodland She-oak, rapid regrowth wattles. • 1939 – 1999 Missing: key fire sensitive species (Ericaceae, Dilleniaceae, Rutaceae) Crosti et al. 2008

  12. High frequency fire degrades vulnerable, fragmented ecosystems more rapidly Veld Grass in Kings Park

  13. Loss of diversity, resilience, ecological simplification and increase in fire-proneness Before After

  14. Management and climate change impacts Summer 2009/10 drought deaths in Kings Park bushland

  15. Fire Sensitive Ecosystems • Forest • Woodlands • Malletwoodlands • ProteaceousMallee-shrubland • Mallee over Melaleuca • Graniteshrublandandfringing Eucalyptus or Allocasuarinawoodlands • Spongeliteshrubland and mallet woodlands • Montane thicket and mallee-thickets Quartzite Ecodistrict • Banksiashrubland, heaths and Proteaceouspalusplain heath • Allocasuarinashrubland: Yilgarn East, Greenstone • Wetlands and damplands Barrett et al. (2009) Identification and conservation of Fire Sensitive Ecosystems and Species Department of Environment and Conservation

  16. Image: David Edmonds

  17. Image: Joanna Young Poison Hill 23 May 2018

  18. Stirling Range National Park May 2018 Impacted 7 threatened invertebrates, 16 threatened plants (10 CR); Critically endangered Montane Heath and Thicket Ecological Community

  19. Altered ecosystems and species matter Ben Miller Beekeepers Nature Reserve April 2006

  20. Post-fire Return Intervals (climate change will extend the recovery times) • Banksia cuneata20-30 years Lamont et al. (1991) • Banksia goodii 15-20 years Drechsler et al. (1999) • Banksia hookeriana15-18 years. Enright et al. (1996) • Banksia shrubland 10-14 years Enright et al., 2011 • Native heaths, sedges 15 years Meney et al 1998 • Eucalyptus salubriswoodland (GWW) >200y Gosper et al (2013) • Jarrah forest 80-100 years Enright and Thomas 2008

  21. Honey possum (Bradshaw and Bradshaw, 2017) Post fire recovery 25.6y Wilson et al (2014) Banksia woodlands 20-25y fire free to sustain populations Mardo (Hindmarsh and Majer 1997) Common in >40y unburnt forest Christensen and Kimber (1975) Rare in areas regularly [prescribed] burnt

  22. Valentine (2012) < 16 year fire-free reduces reptile fauna Rowley and Brooker (1987) Splendid wren return >12 years post-fire – not winter or spring 1960’s – extinct in Kings Park

  23. Honey Possum

  24. Season of burning impacts species recovery – more so in a drying climate Roche et al (1998). For everything a season. Australian Journal of Ecology 23

  25. Only species evolved to cope with high frequency, aseasonal fire will remain. Extirpated plant species are permanent losses

  26. The protective value of prescribed burning ”… There is as yet no clear scientific agreement concerning the protection or ecological benefits of treating larger areas by FRB …..leverage suggest that FRB programs provide a poor return on investment in terms of area of wildfire reduced relative to area treated by FRB.” Enright N J, Fontaine J B, Westcott V C, Lade J C & Miller B P (2011). Fire interval effects on persistence of resprouter species in Mediterranean-type shrublands. Plant Ecology,212, 2071–2083. Ben Miller

  27. • PB reduces the number of wildfires from 70 per year to ca. 50 and decreases the area being burned by wildfires. • The effect of PB persists for 6 years – When burnt areas over the 6 y period averaged, 71 % of the variation in the mean annual extent of unplanned fire was explained by PB over the same 6 year period. But regression is 0.26: leverage (the area that needs to be burned to protect 1 ha): 4 ha needs to be burned to protect 1 ha. That is : 200,000 ha per year ‘protects’ about 50,000 ha.

  28. Geographic variation in leverage value from prescribed burns Price O F, Penman T D, R.A B, Boer M M & Clarke H (2015). Biogeographical variation in the potential effectiveness of prescribed fire in south-eastern Australia. Journal of Biogeography,42, 2234-2245

  29. Increasing fire frequency produces a more flammable landscape – common feature is >40y is the least flammable Zylstra (2018) Flammability in the Australian alps. Austral Ecology 43

  30. The Kings Park ‘Experiment’ showed Dixon IR et al 1994 Proceedings of Burning Our Bushland conference. Urban Bushland Council

  31. Alternatives : safe, effective and acceptable interventions?Precision detection; rapid suppression; strategic rather than target driven; adaptively manage. Beta Image: JAXA Himawari Monitor Satellite

  32. Our actions today determine the biodiversity of tomorrow Translocated Western Ringtail Possum: Prescribed Burn, Warrangup Spring Reserve, May 2017

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