Ecology and movement of urban koalas adjacent to linear infrastructure in coastal south-east Queensland

Abstract

Abstract. In Redland City, koalas (Phascolarctos cinereus) are in rapid decline as they are exposed to anthropogenic threats such as habitat clearing, dog attacks, vehicle collisions and disease. This study investigated the influence of linear infrastructure on the movement and habitat use of urban koalas. Seven koalas were tracked for up to 28 weeks during the breeding season. Home ranges were calculated for 95% Minimum Convex Polygon (MCP95%) and 95% fixed Kernel Density (FK95%). Koalas responded to the landscape in different ways. Linear infrastructure did not restrict the movements of most koalas. Home ranges varied from 1.1 to 31.5 ha MCP95% and from 5 to 55 ha for FK95%. Koalas mainly used Eucalyptus tereticornis throughout the study site. A variety of non-regionally endemic and regionally endemic trees in urban and remnant vegetation areas were used, suggesting that all trees are potentially koala habitat. At the completion of the study, four koalas remained alive, two were killed by trains and one died from a dog attack. Despite the small sample size and short duration, our results suggest that koalas are able to navigate linear infrastructure; however, the high rates of mortality associated with these movements puts the long-term viability of urban koala populations in doubt.

Failure to Respond to Food Resource Decline Has Catastrophic Consequences for Koalas in a High-Density Population in Southern Australia

“…In the five sampling periods between September 2011 and August 2013, predicted mean total ranges were only 0.5 hectares for females and varied between 0.8 and 1.4 hectares for males. These are similar to ranges reported for other high density populations in areas of high availability of preferred food resources [ 34 ], but much lower than those in other parts of Australia (ranges of up to 300 hectares [ 35 – 37 ]. The small ranges we observed may reflect the high quality and relatively contiguous availability of food resources.…”

Decline causes of Koalas in South East Queensland, Australia: a 17-year retrospective study of mortality and morbidity

“…The results of the current study are in agreement with previous studies from SEQLD 24 and those conducted in other Australian states 5 6 10 11 13 . The high proportion of koalas presented to hospitals with traumatic injuries by MV and their high temporal variability may correlate with infrastructural changes across the koala range 25 26 , particularly during 2001–2005. Although the total number of submissions varied over time, there was a larger number of koalas excluded in 2005 from the data analysis, due to being submitted as healthy animals or with missing information.…”

Analysis of morbidity and mortality of wild koalas in south-east Queensland using passive surveillance data

“…The results of the current study are in agreement with previous studies from SEQLD (Weigler et al, 1987) and those conducted in other Australian states (Speight et al, 2014a, Obendorf, 1983, Griffith et al, 2013, Narayan and Williams, 2016, Canfield, 1987a. The high proportion of koalas presented to hospitals with traumatic injuries by MV and their high temporal variability may correlate with infrastructural changes across the koala range (Dique, Thompson, Preece, Penfold et al, 2003, de Oliveira et al, 2014, particularly during 2001-2005. Although the total number of submissions varied over time, there was a larger number of koalas excluded in 2005 from the data analysis, due to being submitted as healthy animals or with missing information.…”

“…The intense, long-term habitat clearing in QLD (Gordon et al, 2006, Dique, Thompson, Preece, Penfold et al, 2003, de Oliveira et al, 2014 could be leading to starvation in koalas, an issue that has surprisingly not generated much discussion. Most of these clusters also are located within densely populated councils.…”

“…Habitat loss influences koalas directly through loss of shelter and browse, leading to a patchy distributions, and indirectly by forcing dispersal to substantial non-forested habitat causing environmental stress and increased trauma from fragmentation by linear infrastructure (e.g. roads, freeways) (Brown and Grice, 1984, Canfield, 1987d, Ellis et al, 1993, White and Timms, 1994, de Oliveira et al, 2014 Heritage and the Arts, 2014). How koalas respond to these indirect sources of stress from habitat loss have been previously ignored.…”