Dieback and potential implications for koalas

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1 Dieback and potential implications for koalas Chris Allen Senior Threatened Species Officer Office of Environment and Heritage

2 Koala populations South Coast & Southern Tablelands

3 NSW Koala Recovery Plan KOALA BROWSE SPECIES Koala Management Area 5: Central and Southern Tablelands Primary food tree species: Ribbon gum E. viminalis Secondary food tree species: Candlebark E. rubida Yellow box E. melliodora Large-flowered bundy E. nortonii Snow gum E. pauciflora Bundy E. goniocalyx Blakely s red gum E. blakelyi Brittle gum E. mannifera Apple-topped box E. bridgesiana Mountain gum E. dalrympleana Stringybarks/supplementary species: Red stringybark E. macrorhyncha

4 Cooma-Monaro Comprehensive Koala Plan of Management Funded by Environmental Trust Underpinned by Koala Habitat Study NSWRFS hazard reduction program Koala Steering Committee Public exhibition of Plan 2015 Waiting for finalisation by Council Implementation of some parts of Plan including monitoring

5 Koala Habitat Study METHODS Regularised Grid-based Spot Assessment Technique (RG-bSAT) as its primary assessment method one kilometre intersections on topo maps forming the foundation of the grid Intervals between grid-sites at two scales. Across most of the study area they were at 1km intervals while in Numeralla area they were at 500m. Grid-sites located in the field with GPS At each site 30 trees >150 DBH were selected Trees identified to species and forest litter to distance of 1m from the trunk of each tree searched for koala faecal pellets.

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9 Results SUMMARY OF RESULTS FROM 1KM-INTERVAL SITES All Number of sites sampled 186 Number of active sites 84 Proportion active sites 45% Number of trees at active sites 2520 Average activity 10.7% Number of sites >10.0%AL 40 Proportion of >10% active sites 47.60%

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11 Bark-chewing

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13 Bark-chewing Koala pellets were located under many of the chewed trees including those from adults and young animals Footage from movement sensitive cameras confirmed that koalas were doing this Chewing areas were characterised by at least several heavily chewed trees that had been repeatedly chewed over at least several years Many other trees with less extensive chew marks were also observed in some of these areas. This feeding strategy by koalas not reported elsewhere

14 Socio-ecology of lowdensity koala populations Large home-range areas, probably resource driven Similar social structure to higher density populations: dominant male, breeding females form the core of the resident association Young disperse and can travel long distances Once settled, probably high fidelity to home range

15 Habitat sustaining low-density koala populations in SENSW Koalas in SENSW predominately in habitat growing in metasedimentary country. Feeding on a diversity of commonly occurring eucalypts, but with some species more preferred than others Preferred species belong to the eucalypt subgenuses symphyomyrtus (gum and box species) and monocalyptus (stringybark and ash species). Selecting individual trees for higher nutrient and/or lower toxicity levels in browse Complex feeding ecology

16 Koala Monitoring Program AIMS Commence koala monitoring program as recommended by the draft Comprehensive Koala Plan of Management for the Cooma- Monaro LGA. A three yearly-reassessment of koala occupancy rates is undertaken at no less than 50 randomly selected macro field-sites from the 186 originally sampled in the study. Undertake a preliminary assessment of the extent and severity of dieback of the preferred koala browse species Eucalyptus viminalis in the assessment area.

17 KOALA SURVEY USING REGULARIZED GRID-BASED SPOT ASSESSMENT TECHNIQUE (RGb-SAT) Recorder M Lems Date 6/24/2020 Location ID #N/A Photo #'s Study Area Southern HighlandsP-easting P-northing Tenure Reserve S-easting S-northing Designation Coornartha NR A-level % GPS error 5 Soil Landholder NSW # Koalas 0 Datum: GDA94 Soil type Clay loam Team Members M Lems, R Summers, C Allen, D Hunt, L Mclachlan, M Eccleston Soil depth Moderate Access difficulty Moderate OTHER FAUNA: Pellets; Digs; IMPACTS Site difficulty Easy Observation; Nest; Call; or Mound Severity 0-3 Est Decade Obs Type Plot radius (m) 21 Macropod Pellets BT Possum Pellets Fire 0 Grid (m) 1000 Wombat Pellets RT Possum TSI 0 LN Ban'coot Lyrebird Intensive log 0 Crown cover %(>5m) 20 LN Potoroo Bell minor Selective Log 's Guesstimate Euc crown cover % 20 YB Glider Goat SAPLINGS AND OLDER CLASSES Shrub cover % (<5m) 0 Rabbit Deer Pellets Count Percentage Ground cover % 50 G.Glider Canine Trees<150mm Myrtaceae 30 Exposed rock % 10 Other Echidna digs Senescent 2 Allocasuarina Overall Condition Good No of Bandi/Potoroo digs within 5m of CT Stags 1 Other 70 Fuel Surface Fine Fuel Near-Surface FF % SFF& NSFF Combined Elevated Bark Overall Hazard Low 40 Low Low Low Low Trees recorded clockwise on N bearing from centre tree If uncertain of euc species, sample buds/caps/leaves & photograph Tree no. Tree Species DBH (mm) # Stems Koala Pellets Present? Pellet age Tree Health Score Greater Glider Pellets 1 Eros No 3 No 2 Eros Yes Fresh 3 No 3 Eros No 3 No 4 Eros No 3 No 5 Cend No 5 No 6 Eros No 3 No 7 Cend No 5 No 8 Eros No 1 No 9 Eman No 3 No 10 Eros No 4 No 11 Eros No 4 No 12 Eman No 5 No 13 Eros No 3 No 14 Eman No 4 No 15 Eros No 3 No 16 Eman No 4 No 17 Eman No 4 No 18 Eman No 5 No 19 Eman No 4 No 20 Eros Yes Fresh 4 No 21 Eros No 2 No 22 Eros No 3 No 23 Eros No 3 No 24 Eros No 4 No 25 Eman No 2 No 26 Eros No 2 No 27 Cend Yes Fresh 3 No 28 Eros No 3 No 29 Eros No 2 No 30 Eros No 4 No PLOT COMMENTS Bark Chewing Comments on tree CHECKED ON SITE BY: R Summers

18 Activity-level results for grid-sites in the Numeralla area replicated for survey in May-June 2016 Activity-level results for replicated and additional grid-sites in the Numeralla area

19 Canopy health score for all trees at each of the assessed grid-sites, with each tree given a score between 1-5, the total scores summed and expressed as a percentage of the highest possible score for the site. anopy health score of E. viminalis at each grid-site where this species occurred, expressed as a percentage of the highest possible score for that species at each site.

20 Location ID P_EASTING P_NORTHING A_LEVEL DATE SURVEYED Period 1 Period 2 Period 1 Period % 10.0% 19-Jan Jun % 3.3% 19-Jan-12 2-Jun % 3.3% 23-Apr Jun % 6.7% 18-Nov Jun % 0.0% 28-Oct Jun % 10.0% 13-May-11 3-May % 16.7% 11-Aug Jun % 0.0% 28-Jul-11 3-May % 3.3% 11-Mar-11 4-May % 3.3% 28-Jul May % 0.0% 24-Feb-11 4-May % 10.0% 2-Dec Jun % 0.0% 13-Mar Jun % 26.7% 4-Mar-13 6-May % 13.3% 21-Mar-13 5-May % 10.0% 4-Apr-13 5-May % 3.3% 12-Mar Jun % 23.3% 12-Mar May % 23.3% 9-Jul May % 10.0% 29-Sep May % 0.0% 16-Oct May % 20.0% 24-Aug Jun % 0.0% 24-Aug May % 20.0% 29-Sep May-16 Number of grid-sites assessed Number of inactive sites 6 6 Number of inactive sites Occupancy Rate 75% 75% Average Activity Levels 15% 12% 15 sites 3 sites 3 sites 3 sites # Active in both periods # Inactive in both periods # Inactive in Period 1 and active in Period 2 # Active in Period 1 and inactive in Period 2

21 Conclusions Dieback appears to be extending into the heartland of the koala habitat sustaining the Southern Tablelands koalas. The extent and severity of dieback of E. viminalis, though generally only occurring in small patches, appears greater than at any time in living memory. Dieback symptoms are worse on the western side of Numeralla than the east. In some parts of the Numeralla area there is no evidence yet of stress or dieback of E. viminalis. Although the significance of this species for koalas may sometimes be over-rated its potential loss should be seen as a major threat to the population. On behalf of the Koala Steering Committee we are keen to support an integrated approach to monitoring, research and management responses.

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