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Context Reviews of climate change in Australia have identified that it is imposing additional stresses on biodiversity, which is already under threat from multiple human impacts. Aims The present study aimed to determine the contributions of several factors to the demise of the koala in the Eden region in south-eastern New South Wales and, in particular, to establish to what extent climate change may have exacerbated the decline. Methods The study built on several community-based koala surveys in the Eden region since 1986, verified through interviews with survey respondents. Historical records as far back as the late 19th century, wildlife databases and field-based surveys were used to independently validate the community survey data and form a reliable picture of changes in the Eden koala population. Analysis of the community survey data used a logistic model to assess the contribution of known threats to koalas, including habitat loss measured as changes in foliage projective cover, fire, increases in the human population and climate change in the form of changes in temperature and rainfall, to the regional decline of this species. Key results We found a marked, long-term shrinkage in the distribution of the koala across the Eden region. Our modelling demonstrated that a succession of multiple threats to koalas from land use (human population growth and habitat loss) and environmental change (temperature increase and drought) were significant contributors to this decline. Conclusions Climate change, particularly drought and rising temperatures, has been a hitherto hidden factor that has been a major driver of the decline of the koala in the Eden region. Implications Development of strategies to help fauna adapt to the changing climate is of paramount importance, particularly at a local scale.

The decisions that animals must make to achieve a balance between quantity and quality of resources become more difficult when their habitats are patchy and differ greatly in quality across space and time. Koalas are a prime subject to study this problem because they have a specialised diet of eucalypt leaves and need to balance nutrient and water intake against toxins in the leaves, all of which can change with soil type and climate. Koalas are nocturnal and spend most of the day resting and therefore choose trees for reasons other than feeding, particularly for thermoregulation. We GPS-tracked 40 koalas over 3 yr to determine their shift in tree selection between day and night, and in relation to daily maximum temperature, in a patchy rural landscape in north-western NSW, Australia. The species, degree of shelter, diameter, height and elevation of each visited tree were recorded. We used generalised linear mixed effects models to compare tree use between day and night and maximum daily temperature. Koalas used more feed-trees during the night, and more shelter-trees during the day. They also selected taller trees with more shelter in the day compared with night. As daytime temperatures rose, koalas increasingly selected taller trees at lower elevations. Our results demonstrate that koalas need taller trees, and non-feed species with shadier/denser foliage, to provide shelter from heat. This highlights the need both for the retention of taller, mature trees, such as remnant paddock trees, and the planting of both food and shelter trees to increase habitat area and connectivity across the landscape for arboreal species. Retaining and planting trees that provide optimum habitat will help arboreal folivores cope with the more frequent droughts and heatwaves expected with climate change.

There is significant interest in mining for coal and coal seam gas in Gunnedah in north-western New South Wales, Australia, including the town, the surrounding Liverpool Plains and the Pilliga forests to the west. The achievement of positive outcomes for koala conservation on mined landscapes will require a sound knowledge of koala ecology and local knowledge of koala movements, tree choice and associated threats to the continued survival of koalas, particularly road-kill from increased mining infrastructure. Recent koala research has shown that in 2006 Gunnedah had the largest koala population west of the Great Dividing Range, and the only population in New South Wales that was expanding. A detailed study in 2008-2011 was carried out to determine whether the koalas were using trees that were planted in the 1990s to cope with rising soil salinity. GPS-tracking showed that re-growth trees as young as ten years old could attract koalas. In 2009, the demise of about a quarter of the local koala population from an intense heat-wave provided a foretaste of how habitat and climate change interrelate at the landscape scale. The optimal combinations of tree choice and patch size and shape for habitat restoration are currently being investigated which will be relevant to local coal seam gas and coal mine proposals and ongoing mitigation actions. The Senate enquiry of September 2011 demonstrated the intense public interest in the survival of koala, and its subsequent listing for Queensland and New South Wales under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 further raised its profile and the obligations for management of koalas and their habitat. The research approaches required are discussed and a set of guides is presented for environmental plantings., There is significant interest in mining for coal and coal seam gas in Gunnedah in north-western New South Wales, Australia, including the town, the surrounding Liverpool Plains and the Pilliga forests to the west. The achievement of positive outcomes for koala conservation on mined landscapes will require a sound knowledge of koala ecology and local knowledge of koala movements, tree choice and associated threats to the continued survival of koalas, particularly road-kill from increased mining infrastructure. Recent koala research has shown that in 2006 Gunnedah had the largest koala population west of the Great Dividing Range, and the only population in New South Wales that was expanding. A detailed study in 2008-2011 was carried out to determine whether the koalas were using trees that were planted in the 1990s to cope with rising soil salinity. GPS-tracking showed that re-growth trees as young as ten years old could attract koalas. In 2009, the demise of about a quarter of the local koala population from an intense heat-wave provided a foretaste of how habitat and climate change interrelate at the landscape scale. The optimal combinations of tree choice and patch size and shape for habitat restoration are currently being investigated which will be relevant to local coal seam gas and coal mine proposals and ongoing mitigation actions. The Senate enquiry of September 2011 demonstrated the intense public interest in the survival of koala, and its subsequent listing for Queensland and New South Wales under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 further raised its profile and the obligations for management of koalas and their habitat. The research approaches required are discussed and a set of guides is presented for environmental plantings.

Koalas are prime candidates to study the impact of climate change because they are specialised folivores and lack any ready means of avoiding weather extremes. Koalas are widely but patchily distributed throughout eastern mainland Australia. Efforts to protect them from landscape-scale threats have been identified in the NSW 2008 Koala Recovery Plan, the 2010 NSW Priorities for biodiversity adaptation to climate change and the 2009-14 National Koala Conservation and Management Strategy. The statements in the formal strategies and recovery plans identify a number of problems, two of which we address in this paper. The first problem is that of extreme weather and the second is the change of leaf quality from rising levels of carbon dioxide. This paper capitalises on our field study in Gunnedah, in north-west NSW, which examined a 1990s success story where the local koala population benefited from the plantings of trees and shrubs to hold down the water table in the face of a rising salinity crisis. In late 2009, heatwaves killed an estimated 25% of the Gunnedah koala population. This foreshadows how increased climate variability will impact on koala populations. In 2008, chlamydiosis - a disease causing infertility - had been established as being present in the Gunnedah population. The likely spread of this disease throughout the Gunnedah koala population presents a further challenge to wildlife managers in the context of a changing climate. The potential indirect effects of global climate change - how increasing concentrations of atmospheric CO2 may reduce the availability of the nutrients in Eucalyptus foliage to koalas - is described and the implication drawn that elevated concentrations of atmospheric CO2 may threaten some populations of free-ranging koalas. The Liverpool Plains are among Australia's prime agricultural landscapes where the conservation of biodiversity occurs largely on private land. Consequently, we need to integrate climate change adaptation with