Jessica Oates and Brent Johnson

The Quolls of Poondano: A Case Study

BackgroundThe project targets Channel Iron Deposits (CID) that are expressed as both bedded formations (Poondano South West) and exposed mesa formations (Poondano Central). Small 4.2 million tonne resource.

• Fauna assessment of the Poondano area by Bamford Consulting in 2008.• Northern quolls were detected on Poondano Central (Outback Ecology 2009a).• Rapallo undertook a targeted trapping program across Poondano Central and Poondano West (Rapallo 2010).• Referred to the Department of Sustainability, Environment, Population, Water and Communities and listed as a

controlled action.• Further trapping by Rapallo in April 2011, which focused on understanding the regional distribution of the northern

quoll (Rapallo 2011). • Genetic investigations undertaken: Population structure analysis shows that they clearly group well within a

‘Pilbara’ cluster, undifferentiated from animals that have been sampled from the Pilbara previously.• Mining at Poondano Central commenced October 2011.• Approval Condition required development of a Fauna Management Plan to manage potential impacts from mining.• Monitoring survey in July 2012 for the northern quoll across the impact and control sites (Rapallo 2012). Northern

quolls were captured at all trapping locations, with a total of 69 individuals recorded.• 2012 results indicated that the population surrounding Poondano Iron Ore Project was robust, although

displacement was observed at Poondano Central.• Monitoring and radio-tracking May – July 2013 undertaken by Astron Environmental Services.

Poondano Mesa

Poondano Central

Poondano West

2013 Monitoring

• A similar methodology to Rapallo (2012) was employed for the northern quoll trapping program.

• A total of 100 cage traps at eight sites were monitored for between 4 and 7 nights, resulting in a total of 610 trap nights.

• Trap sites were re-established at the same sites two new ‘control’ sites.

Study Area

Data Analysis

• A spatially explicit capture-recapture framework enabled explicit modelling of animal (e.g. sex, maturity, learning), trap (e.g. distance from impact, habitat zone, trap type) and temporal (e.g. seasonal differences) effects on the distribution of a spatially heterogeneous population.

• secr package in R.• The basic model focuses on three parameters:

– population density– probability of detection per night– a scale parameter describing the home range extent of the ‘average’

animal.

• These population parameters were estimated individually for each year and for each population site surveyed.

Trapping Results

Site No. Individual Quolls No. Total Captures Trap Success (%) Male : Female Ratio

Poondano Central 16 30 20.1 0.9:1

Poondano West 9 21 30 1.3:1

Control East 3 3 12.5 0:1

Control West 6 14 38.9 0.5:1

Granite Outcrop 11 19 45.2 0.6:1

Northern Outcrop 9 22 44.9 1:1

Poondano East 7 33 30 2.5:1

Southern Granites 20 31 23.8 0.8:1

TOTAL 77 173 28.4% 0.83:1

Year SiteDensity Estimate (no. quolls per ha)

Detection Probability Population Estimate

2010Poondano West 0.0453 0.1718 30.5

Poondano Central 0.0658 0.0307 23.4

2011

Poondano West 0.1481 0.0241 11.5

Poondano Central 0.0972 0.0076 20.0

Granite Outcrop 0.5011 0.2348 14.8

Northern Outcrop 0.2397 0.0711 6.5

2012

Poondano West 0.0478 0.0400 3.7

Poondano Central 0.0193 0.0673 11.7

Granite Outcrop 0.4987 0.0575 14.8

Northern Outcrop 0.5069 0.0528 16.5

Southern Granites 0.2236 0.0332 50.4

Poondano East 0.0062 0.0605 7.3

2013

Poondano West 0.1250 0.0361 9.7

Poondano Central 0.0953 0.0123 20.7

Granite Outcrop 0.5945 0.0790 17.6

Northern Outcrop 0.3153 0.1106 10.2

Southern Granites 0.1599 0.0351 32.1

Poondano East 0.0419 0.1936 7.9

Control East 0.1504 NA 3

Control West 0.2991 0.0724 6.4

The population parameters of density, detectability and home range extent of the average animal were further modelled as a function of

both sex of the individual animal (male or female) and or behaviour of the individual animal (i.e. learning).

No consistent influence of any of these factors on any of the population parameters when compared across mesas and years, as measured by

the Akaike Information Criterion (AIC).

Quoll population estimates (± SE) for each monitoring site between 2010 and 2013

PW – Poondano West, PC – Poondano Central, GO – Granite Outcrop, NO – Northern Outcrop, SG – Southern Granites, PE – Poondano East

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2010 2011 2012 2013

Popu

latio

n Es

timat

e

Year

PW

PC

GO

NO

SG

PE

Activity at Poondano West

Mining at Poondano Central

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0.1

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Den

sity

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o. q

uolls

/ha)

Distance from current activity at Poondano West (km)

2010

2011

2012

2013

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Dens

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(no.

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lls/h

a)

Distance from previous mining at Poondano Central (km)

2010

2011

2012

2013

• Density, detectability and movement extent were also modelled as a function of distance from disturbance.

• Distance from Poondano West, which is considered to be currently active mining

• Distance from Poondano Central, which is considered to be previously mined.

Quoll numbers were not influenced by distance to current or previous disturbance

Individual Movements of Quolls

Summary of Population Modelling Results

• Current data suggests that the northern quoll population within and surrounding the Poondano Iron Ore Project remains stable and robust.

• Short-term movement (or displacement) of quolls related to disturbance from mining activities.

• High site fidelity to rocky habitats – no use of riparian habitats.• Number of other factors that are considered likely to affect the :

– overall population numbers• Rainfall• Resource availability• Fire

– spatial distribution of quolls and re-colonisation of previously disturbed areas• Elevation• Slope• Refuge (cave/crevice) retention and boulder size• Landform• Vegetation

Refuge Preference

• Zones of high refuge opportunity• No recorded use of hollows or burrows• Strong preference for rock caves, crevices & boulder piles• Mining infrastructure is utilised – buildings, laydowns, waste

rock dumps, vehicles and machinery• Strong site fidelity shown by females and some males• Movement between mesas & granite outcrops mainly

demonstrated by males• 2 – 3 km movements common• Home range data yet to be analysed

Mining Activity and Interactions

Rehabilitation(commencing 2013)

Rough is good!

• Plan prior to mining commencement• Retain material• Heaps are better than level spread• Provide clear prescriptions (SWPs) and training to machine

operators

Threats

• Habitat loss– Foraging– Refugia

• Human interactions• Feral predators• Cane toads in Petermarer Creek?

Summary of Findings• This is a significant northern quoll population• The population remains robust• Predation not recorded in radiotracking study• High site fidelity displayed• Strong refuge preference for rocky habitat over riparian• Mining infrastructure needs to be considerable distance from

preferred habitat to prevent interactions• Management and staff awareness is essential• Housekeeping needs to be maintained• Correctly rehabilitated sites will be utilised• Clear prescription for rehab needs to be written prior to mining

activities

Recommendation for Research at Poondano

Value add• Collect and analyse a number of habitat covariates from monitoring sites

so that these can be linked to the spatial distribution of quolls, including landform, geology, elevation, slope, aspect, measure of boulder size, vegetation.

• Collect and analyse a number of aspatial trip descriptors such as a drought index, rainfall preceding the monitoring trip, Normalised Difference Vegetation Index (NDVI) value for the project area, so that these can be linked to the temporal changes in quoll numbers.

Plus• Monitoring of rehabilitated areas to assess re-colonisation trends and

requirements (Adaptive management?)• Survey of outlying mesas and outcrops to broaden regional knowledge.

Acknowledgements:

• Polaris Metals Pty Ltd• Astron Team

Questions?