Patchy resources and multiple threats: How do koalas navigate an urban landscape?

Whisson, Desley A.; Zylinski, Simeon; Ferrari, Ashlee; Yokochi, Kaori; Ashman, Kita R.

doi:10.1016/j.landurbplan.2020.103854

Cited by 11 publications

(4 citation statements)

References 28 publications

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“…Our results further suggest that exposure is related to age-dependent patterns of movement, as both exposure and movement increased proportionally with increasing koala age. The home ranges observed in this study (males = 6.1 ha, females = 3.3 ha) are similar to those of koalas residing in another urban coastal habitat in Victoria, Australia (males = 9.1 ha, females = 4.3 ha) 45 , and general patterns of movement observed may reflect a combination of age and resource-limited 27 , 45 , 46 effects. Exposure ultimately appears to be dependent upon multiple demographic and habitat related factors, and the interactions between them.…”

Section: Discussionsupporting

confidence: 73%

The environmental and ecological determinants of elevated Ross River Virus exposure in koalas residing in urban coastal landscapes

Johnson

Robbins

Gyawali

et al. 2021

Sci Rep

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Koala populations in many areas of Australia have declined sharply in response to habitat loss, disease and the effects of climate change. Koalas may face further morbidity from endemic mosquito-borne viruses, but the impact of such viruses is currently unknown. Few seroprevalence studies in the wild exist and little is known of the determinants of exposure. Here, we exploited a large, spatially and temporally explicit koala survey to define the intensity of Ross River Virus (RRV) exposure in koalas residing in urban coastal environments in southeast Queensland, Australia. We demonstrate that RRV exposure in koalas is much higher (> 80%) than reported in other sero-surveys and that exposure is uniform across the urban coastal landscape. Uniformity in exposure is related to the presence of the major RRV mosquito vector, Culex annulirostris, and similarities in animal movement, tree use, and age-dependent increases in exposure risk. Elevated exposure ultimately appears to result from the confinement of remaining coastal koala habitat to the edges of permanent wetlands unsuitable for urban development and which produce large numbers of competent mosquito vectors. The results further illustrate that koalas and other RRV-susceptible vertebrates may serve as useful sentinels of human urban exposure in endemic areas.

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Section: Discussionsupporting

confidence: 73%

The environmental and ecological determinants of elevated Ross River Virus exposure in koalas residing in urban coastal landscapes

Johnson

Robbins

Gyawali

et al. 2021

Sci Rep

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“…Using the same methods, Telfer and Griffiths (2006) adopted the 50% isopleth in their short-eared rock wallaby (Petrogale brachyotis) study; and Moseby et al (2009) adopted a 60% isopleth for their study on feral cats and foxes. For Koala (Phascolarctos cinereus, henceforth koala) studies, Whisson et al (2020) employed an animal-determined method (Powell 2000) to use 60% and 70% isopleths to define core areas within urban areas; de Oliveira et al (2014), Goldingay and Dobner (2014), Matthews et al (2016), Phillips (2016) 2) plots ; (3) transects (Hindell and Lee 1987;Dique et al 2003); and (4) faecal pellet examination to determine food resources (Ellis et al 1999). Current habitat management primarily relies on information derived from these data.…”

Section: Introductionmentioning

confidence: 99%

“…For Koala ( Phascolarctos cinereus , henceforth koala) studies, Whisson et al . (2020) employed an animal-determined method (Powell 2000) to use 60% and 70% isopleths to define core areas within urban areas; de Oliveira et al . (2014), Goldingay and Dobner (2014), Matthews et al .…”

Section: Introductionmentioning

confidence: 99%

Remote sensing shows south-east Queensland koalas (Phascolarctos cinereus) prefer areas of higher tree canopy height within their home ranges

Mitchell

Soto‐Berelov²,

Jones³

2023

Wildlife Res.

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Context. Home range studies allow investigation of faunal habitat use within a well-defined area, and for some species, the concept of 'core' and 'non-core' home ranges provides the means to examine how resource use varies within home ranges. Taking this approach, we investigated whether koalas preferentially used areas of taller forest canopy within home ranges. After an extensive examination of data quality and home range estimation methods, we used remote sensing techniques to provide canopy height information at high resolution. Aims. In many areas, koalas prefer taller individual trees at the plot scale; our aim was to investigate whether koalas prefer forest areas with higher canopy height within their home ranges. Methods. In our southeast Queensland study area, we developed a canopy height model (CHM) from airborne LiDAR (Light Detection and Ranging) data. Existing radio telemetry and GPS data from 135 koalas were used to generate home ranges using 95% kernel density estimators, and 50% kernels represented core home ranges. Some home ranges occupied more than one forest type (Regional Ecosystem -RE); we treated each RE as an individual patch, and used 225 patches in our analysis. We intersected the 95% kernels with the CHM, and used hierarchical spatial clustering to derive four categorical canopy height classes within each patch. We then compared differences in height class area proportions between core and non-core areas for each patch. Key results. The highest of the four canopy height classes comprised a significantly higher proportion of core areas (42.3%) than non-core areas (30.7%). Classes 2 and 3 were evenly distributed, and the proportion of Class 4 (lowest canopy height) was 20.3% of non-core areas and 11.0% in core areas. Results were similar for REs grouped by Land Zone and individual REs. Conclusions and implications. We conclude that areas of higher canopy are an important habitat resource for koalas. We have, for the first time, examined resource variability within entire koala home ranges using remote sensing, and our methods demonstrate an avenue for further research using other forms of remote sensing. Classified canopy height models could also be used for strategic conservation planning, and at population-level koala habitat management when combined with other relevant habitat factors.

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“…The koala (Phascolarctos cinereus) is an iconic Australian mammal that fits within this body mass range (6-7 kg, Ellis and Bercovitch 2011). Koalas are still found in some urban environments (Goldingay and Dobner 2014;Whisson et al 2020) but they face a range of anthropogenic threats such as motor vehicle collisions (McAlpine et al 2006;Lunney et al 2022aLunney et al , 2022b, domestic animal attacks (Rundle-Thiele et al 2019;Lunney et al 2022c) and chlamydia infection (McCallum et al 2018;Quigley and Timms 2020). Fundamentally, the extensive clearing of forests to facilitate urbanisation has had immediate impacts on the viability of landscapes for koalas to persist (McAlpine et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Database records of koalas (Phascolarctos cinereus) in northern Sydney

Mo,

Lee,

Radosavljevic

et al. 2023

Aust. Mammal.

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This study examined records of koalas (Phascolarctos cinereus) in northern Sydney held in online biodiversity databases. There were 221 unique records distributed across the Northern Beaches, Ku-ring-gai, Hornsby and Hills Shire local government areas from 1788 to 2022, with records from the Northern Beaches local government area comprising 68% of this dataset. Records from the 1970s represented 41% of the dataset (90 records), while there were only 42 records from 2000 to 2022. Post-2000 records were spread broadly, showing no major contraction in distribution compared to the spread of earlier records, but with a notable absence of more recent records on the Barrenjoey Peninsula, a previously documented species stronghold. Substantial proportions of records were found in both protected reserves and privately-owned lands, which alludes to the value of the former but also shows that koala conservation in this capital city cannot rely solely on protected reserves. The 2000–22 records were widely distributed across 15 plant community types and areas of non-native vegetation, probably reflecting breeding and dispersal movements more than specific habitat selection. Possibly due to the same influences, none of the 2000–22 records were matched to areas represented by the Koala Habitat Suitability Model, a prediction model for spatial distribution of potential koala habitat across NSW, with a high habitat suitability score (greater than 0.85). We therefore recommend systematic on-ground surveys to clarify the patterns observed from the records.

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Patchy resources and multiple threats: How do koalas navigate an urban landscape?

Cited by 11 publications

References 28 publications

The environmental and ecological determinants of elevated Ross River Virus exposure in koalas residing in urban coastal landscapes

The environmental and ecological determinants of elevated Ross River Virus exposure in koalas residing in urban coastal landscapes

Remote sensing shows south-east Queensland koalas (Phascolarctos cinereus) prefer areas of higher tree canopy height within their home ranges

Database records of koalas (Phascolarctos cinereus) in northern Sydney

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