Relationships between human-induced habitat disturbance,

stressors and disease in Koalas

Clive McAlpine

Centre of Excellence for Environmental Decisions (CEED) and Centre for Spatial Environmental Research (CSER), Landscape

Ecology and Conservation Group, The University of Queensland

Disturbance - Wildlife Disease Review

• Recent review of human-induced disturbance and wildlife disease prevalence

• 25 studies were reviewed (20 experimental & 5 review)

• 56% of studies indicated an increase in disease prevalence

• Five key topics identified for future research

1. Influence of urban landscapes

• 36% incorporated urban parameters

• No detailed multi-scale assessments conducted

2. Spatial and Temporal Factors

• No multi-scale assessments conducted

• All studies used general disturbed vs. undisturbed comparisons

3. Influence of environmental stressors (e.g. climate change)

• Primarily focused on marine organisms or amphibians

• Little attention paid to influences on host ecology and physiology and its link with disease prevalence

4. Link between physiological stress and disease prevalence

4. Limited information available on disturbance-stress & stress-disease links

5. No studies have assessed the disturbance-stress-disease link

5. Sexual transmitted diseases (STDs)

• No studies have assessed the link between disturbance-STDs

DERM Koala Disease Project

Objectives:

1. Develop a conceptual model of potential causal relationships between environmental stressors and the prevalence of disease in Koalas

2. Conduct a detailed analysis of the influence of spatial and temporal scale parameters on disease prevalence & mortality rates using:

a) Records from the Moggill Koala Hospital & Australian Wildlife Hospital

b) Radio-tracking records for SEQ Koala populations

3. Conduct a comparative analysis of the link between physiological stress and disease prevalence

4. Integrate information from Objective 2 into current population models

5. Provide recommendation for improved conservation management outcomes

Diseased Koalas recorded (1997- current) Brisbane Metropolitan Area and surrounds

Brisbane CBD

1997-1999 2000-2002

2003-2005 2006-2008 2009-2011

Brisbane Metropolitan Area

Including:

• Brisbane • Logan • Redlands

2000-2002

2003-2005 2006-2008 2009-2011

1997-1999 Northern Brisbane

Including:

• Murrumba Downs • Mango Hill • North Lakes • Kallangur • Narangba

Habitat Loss

&

Fragmentation

(e.g. habitat %, patch size &

isolation)

Climate Variability

(e.g. rainfall (mm), drought)

Land-use Intensity

(e.g. roads, urban

development, dog

densities)

Koala Disease

Conceptual Model

Physiological

Stress

Habitat Loss

&

Fragmentation

(e.g. habitat %, nearest isolation)

Climate Variability

(e.g. Heatwaves, drought)

Land-use Intensity

(e.g. roads, urban

development, dog

densities)

Koala Disease

Conceptual Model

Physiological Stress

The Next Step? • Understand the causal relationships between multi-scale

environmental stressors (spatial & temporal) and disease prevalence

• Identify and understand the potential link between disturbance, physiological stress & disease

• Quantify the impacts of disease on breeding and fecundity rates (e.g. J. Rhodes mortality model)

• Use model outcomes to assess and develop appropriate conservation methods to reduce vulnerability of wild koala populations to disease