Post on 09-Sep-2018
transcript
Title Sub-heading
27/10/2015
Leadbeater’s Possum – Impacts of fire
Jenny Nelson
Arthur Rylah Institute
Department of Environment, Land, Water and Planning
Leadbeater’s Possum Gymnobelideus leadbeateri
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• Small, arboreal marsupial
• Related to Sugar Glider but no gliding membrane, so leaps
• Endemic to Victoria
• Victoria’s faunal emblem
Distribution
• Restricted distribution
- 70 x 80 km in the Central Highlands
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Habitat
Montane Ash Forest
- Mountain Ash
- Alpine Ash
- Shining Gum
Sub-alpine Woodland
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Lowland Floodplain Woodland
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Habitat requirements
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• Smooth-barked eucalypts – shedding bark used for nests & foraging
Habitat requirements
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• Hollow-bearing trees – nesting and shelter
Snow Gum hollows
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Habitat requirements
• Wattle & dense well-connected vegetation for food & movement
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Ideal habitat
• Multi-aged forest
• Abundant live & dead hollow-bearing trees
• Dense mid-storey vegetation
• Wattle
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Diet
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• Plant and insect exudates (80% of diet)
- Acacia gum
- Eucalypt nectar and sap
- Sweet exudates of psyllids
• Arthropods (20% of diet)
- Tree crickets
- Beetles
- Moths
- Spiders
Conservation status
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• Particularly vulnerable to disturbances - restricted distribution - depends on hollow-bearing trees; suitable hollows take >100 years to develop - habitat subject to disturbances
• Listed under FFG Act in Victoria
- Endangered on Advisory List of Threatened Vertebrate Fauna
• Critically Endangered under federal EPBC Act
- Recently upgraded from Endangered
Bushfire in the Central Highlands
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• Primary form of large-scale disturbance in Leadbeater’s Possum habitat
• On average bushfire every 10 years
• Most intensive & extensive fires in 1939 & 2009
• Climate change may lead to more bushfires
1939 & 2009 bushfires, key differences
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• only known from Central Highlands • severely impacted by 2009 fires – half range burnt • not recorded in burnt habitat
• 1939 fires burnt majority of Central Highlands ash, forest now 74 years old - extensive areas of old growth prior to 1939 resulted in lots of stags
• 2009 fires burnt 34% of potential habitat - resulting dead trees too small to provide suitable hollows
Old growth Mountain Ash Forest, photo Dan Harley
Impact of fire
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• Impact of fire depends on: - intensity (how hot) - frequency (interval b/t fires) - location (where in range) - extent (area affected)
• Ash trees killed by high intensity fires leading to single-aged stands, with nesting sites in dead trees or surviving live trees
• If fire interval < 20-30 years then ash trees replaced by other species
• Promotes wattle regeneration
Impact of fire
• Extensive, high intensity or frequent bushfires increase the risk of extinction of Leadbeater’s Possum
– Possum mortality
– Loss of hollow-bearing trees
– Destruction of food resources
– Alters stand structure
– Isolates surviving populations
• Patchy or lower intensity bushfires result in multi-aged forests within which hollow-bearing trees may be retained, or can develop
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2009 Black Saturday bushfires
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• 2009 fires burnt 34% of range of Leadbeater’s Possum
• No possums found in burnt habitat - ANU, 161 long-term monitoring sites, no possums on 68 burnt sites - Zoos Victoria, 95% known population killed on Lake Mountain - ARI, 180 sites surveyed in 2012, no possums on 30 burnt sites
• Surviving populations fragmented
2009 bushfire & Leadbeater’s Possum records
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Sub-alpine woodland burnt in 2009
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Montane ash forest burnt in 2009
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ARI – Forest Biodiversity Project
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• Improve knowledge of distribution & habitat use of priority threatened fauna to inform management
• Broad-scale survey to locate priority areas for Leadbeater’s Possum - 180 survey sites throughout range - developed occupancy model to predict strongholds
• Persistence of colonies in ‘fire refuges’ - surveyed 37 unburnt patches within the 2009 fire area
Predicted strongholds post-2009 fire
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Recovery potential in bushfire area
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• Unburnt patches within 2009 fire area
• 37 refuges surveyed
• Recorded at 6 sites (16%)
• Important for future recolonisation of burnt area
Fire management
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• Incorporate known colonies & high quality habitat into fire operations & risk landscapes planning
• No fuel reduction burning in Leadbeater’s Possum habitat
• Active fire management activities to reduce risk of bushfire impacting on known colonies & high quality habitat
• Develop bushfire recovery protocols
Managing bushfire risk
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• Phoenix Rapidfire – bushfire simulation tool
- predict risk to Leadbeater’s Possum habitat & known colonies
- where to target management to reduce bushfire risk
Bushfire recovery protocols
• Management actions that may be undertaken post-bushfire to assist recovery of known colonies
• Aim to improve key habitat requirements:
- availability of den sites
- vegetation connectivity
- food
• Depends on location & significance of known colonies, severity of fire & current management
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