Climate change and the koala<i>Phascolarctos cinereus</i>: water and energy

Ellis, William; Melzer, Alistair; Clifton, Irene Delma; Carrick, F. N.

doi:10.7882/az.2010.025

Cited by 45 publications

(52 citation statements)

References 18 publications

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“…Although we cannot unequivocally link climatic conditions or land clearing with changes in koala populations, there is evidence from previous work that allows us to assign their effects to our findings (Gordon et al 1988;Cogger et al 2003;McAlpine et al 2006b;Ellis et al 2010).…”

Section: Weather Conditions and Land Clearingmentioning

confidence: 58%

“…Their area of occupancy contracted mainly to the most optimal habitat along creeks and rivers, with little use of habitat away from water courses. The decline coincided with a period of 4-5 years where there was a combination of low summer rainfall and an above average number of very hot days, which mimic the predicted direction of climate change in the region and are known to affect koala survival (Gordon et al 1988;Gordon et al 1990;Ellis et al 2010). The changes in distribution (both the extent of occurrence and the area of occupancy) reflect the koalas' response to alterations in their environment and ability to disperse in south-west Queensland.…”

Section: Discussionmentioning

confidence: 95%

“…Evidence from previous studies indicates that hot days and low rainfall can have severe impacts upon koala populations, either directly by causing physiological stress or indirectly by affecting the nutrient and water content in eucalypt leaves (Gordon et al 1988;Clifton et al 2007;Ellis et al 2010). We examined climate data from the Bureau of Meteorology for the major towns across the region from 1990 to 2009 to see if there had been significant changes in climatic conditions.…”

Section: Weather Conditions and Land Clearingmentioning

confidence: 99%

“…This temperature threshold was chosen for several reasons. In their study of koala metabolism and heat balance, Degabriele and Dawson (1979) stated that the body temperature, respiratory rate and evaporative water loss of koalas rose rapidly when air temperatures were above 30 C. Bioclimatic modelling conducted by Adams-Hosking et al (2011) identified that koalas occur in areas with maximum summer temperatures of under 37.7 C. However, Ellis et al (2010) found that, in central Queensland, the temperatures in trees used by koalas for shelter in the summer could be around 2 C cooler than ambient air temperature, thereby moderating the effect on thermoregulation. We accordingly picked 40 C as an air temperature that would result in significant physiological stress for koalas.…”

Section: Weather Conditions and Land Clearingmentioning

confidence: 99%

“…Koalas are susceptible to climatic extremes, particularly heatwaves and droughts, which also affect the quality of nutrients and moisture available in their diet (Cork and Braithwaite 1996;Moore and Foley 2000). There is evidence that koalas can modify their behaviour and physiology to increase water intake if necessary (Krockenberger 2003;Ellis et al 2010), but climatic stress on trees can lead to widespread leaf fall and subsequent crashes in koala populations (Gordon et al 1988;Gordon et al 1990). For example, Gordon et al (1990) found, in northern and western Queensland, that the variability in rainfall and its effect on food sources was probably the most important factor affecting koala populations, although in the eastern region it was high infertility and prevalence of cystitis.…”

Section: Introductionmentioning

confidence: 99%

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Drought-driven change in wildlife distribution and numbers: a case study of koalas in south west Queensland

et al. 2011

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Context. Global climate change will lead to increased climate variability, including more frequent drought and heatwaves, in many areas of the world. This will affect the distribution and numbers of wildlife populations. In south-west Queensland, anecdotal reports indicated that a low density but significant koala population had been impacted by drought from [2001][2002][2003][2004][2005][2006][2007][2008][2009], in accord with the predicted effects of climate change.Aims. The study aimed to compare koala distribution and numbers in south-west Queensland in 2009 with pre-drought estimates from 1995-1997.Methods. Community surveys and faecal pellet surveys were used to assess koala distribution. Population densities were estimated using the Faecal Standing Crop Method. From these densities, koala abundance in 10 habitat units was interpolated across the study region. Bootstrapping was used to estimate standard error. Climate data and land clearing were examined as possible explanations for changes in koala distribution and numbers between the two time periods.Key results. Although there was only a minor change in distribution, there was an 80% decline in koala numbers across the study region, from a mean population of 59 000 in 1995 to 11 600 in 2009. Most summers between 2002 and 2007 were hotter and drier than average. Vegetation clearance was greatest in the eastern third of the study region, with the majority of clearing being in mixed eucalypt/acacia ecosystems and vegetation on elevated residuals.Conclusions. Changes in the area of occupancy and numbers of koalas allowed us to conclude that drought significantly reduced koala populations and that they contracted to critical riparian habitats. Land clearing in the eastern part of the region may reduce the ability of koalas to move between habitats.Implications. The increase in hotter and drier conditions expected with climate change will adversely affect koala populations in south-west Queensland and may be similar in other wildlife species in arid and semiarid regions. The effect of climate change on trailing edge populations may interact with habitat loss and fragmentation to increase extinction risks. Monitoring wildlife population dynamics at the margins of their geographic ranges will help to manage the impacts of climate change.

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Section: Weather Conditions and Land Clearingmentioning

confidence: 58%

Section: Discussionmentioning

confidence: 95%