Leadbeater s Possum Impacts of fire

Transcription

1 Leadbeater s Possum Impacts of fire Title Sub-heading Jenny Nelson Arthur Rylah Institute Department of Environment, Land, Water and Planning 27/10/2015

2 Leadbeater s Possum Gymnobelideus leadbeateri Small, arboreal marsupial Related to Sugar Glider but no gliding membrane, so leaps Endemic to Victoria Victoria s faunal emblem 2

3 Distribution Restricted distribution - 70 x 80 km in the Central Highlands 3

4 Habitat Montane Ash Forest - Mountain Ash - Alpine Ash - Shining Gum 4

5 Sub-alpine Woodland 5

6 Lowland Floodplain Woodland 6

7 Habitat requirements Smooth-barked eucalypts shedding bark used for nests & foraging 7

8 Habitat requirements Hollow-bearing trees nesting and shelter 8

9 Snow Gum hollows 9

10 Habitat requirements Wattle & dense well-connected vegetation for food & movement 10

11 Ideal habitat Multi-aged forest Abundant live & dead hollow-bearing trees Dense mid-storey vegetation Wattle 11

12 Diet 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 12

13 Conservation status 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 13

14 Bushfire in the Central Highlands 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 14

15 1939 & 2009 bushfires, key differences 1939 only known fires from burnt Central majority Highlands of Central Highlands ash, forest severely now impacted 74 years by 2009 old fires half range burnt - extensive areas of old growth prior to 1939 resulted in lots of stags not recorded in burnt habitat 2009 fires burnt 34% of potential habitat - resulting dead trees too small to provide suitable hollows Old growth Mountain Ash Forest, photo Dan Harley 15

16 Impact of fire 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 singleaged stands, with nesting sites in dead trees or surviving live trees If fire interval < years then ash trees replaced by other species Promotes wattle regeneration 16

17 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 17

18 2009 Black Saturday bushfires 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 18

19 2009 bushfire & Leadbeater s Possum records 19

20 Sub-alpine woodland burnt in

21 Montane ash forest burnt in

22 ARI Forest Biodiversity Project Improve knowledge of distribution & habitat use of priority threatened fauna to inform management Broad-scale survey to locate priority areas for Leadbeater s Possum 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 22

23 Predicted strongholds post-2009 fire 23

24 Recovery potential in bushfire area Unburnt patches within 2009 fire area 37 refuges surveyed Recorded at 6 sites (16%) Important for future recolonisation of burnt area 24

25 Fire management 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 25

26 Managing bushfire risk Phoenix Rapidfire bushfire simulation tool - predict risk to Leadbeater s Possum habitat & known colonies - where to target management to reduce bushfire risk 26

27 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 27

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