A koala and its baby. Koalas are susceptible to heat stress, and recent Australia temperatures have been beyond their 'climatic threshold'. Photo: John Giustina / Getty Images

Australia's iconic marsupial is at risk from shrinking habitats, road traffic and dog attacks – and increasingly, global warming
By Neena Bhandari for IPS, part of the Guardian Environment Network   
30 April 2013

SYDNEY (guardian.co.uk) – Australia's iconic marsupial is under threat. Formerly hunted almost to extinction for their woolly coats, koalas are now struggling to survive as habitat destruction caused by droughts and bushfires, land clearing for agriculture and logging, and mining and urban development conspire against this cuddly creature.

In the past 20 years, the koala population has significantly declined, dropping by 40 percent in the state of Queensland and by a third in New South Wales (NSW). The Australian Koala Foundation (AKF) estimates that there are between 45,000 and 90,000 koalas left in the wild.

Shrinking habitat and climate change is compounding the risk of disease, while attacks from feral and domestic dogs and road accidents add to a long list of risks that this arboreal mammal faces as it moves across the landscape in search of food.

It is estimated that around 4,000 koalas are killed each year by dogs and cars alone.

Climate scientists warn that forecasts of longer dry periods, rises in temperature, more intense bushfires and severe droughts pose a significant risk to the koala, which is endemic only to Australia.

"In the past decade, we have experienced the hottest temperatures on record followed by floods and cyclones. The koalas are highly susceptible to heat stress and dehydration," University of Queensland koala expert Dr. Clive McAlpine told IPS.

"Our climate envelope modelling found that koalas occur at a maximum temperature of 37.7 degrees centigrade. Across western Queensland and New South Wales, temperatures remained in the mid to high 40-degree centigrade (range) for consecutive days, pushing them beyond their climatic threshold."

The name koala is derived from the aboriginal word meaning "no drink", as the creatures feed on and derive much of their moisture needs from the nutrient-poor eucalyptus leaves. An individual Koala may have to consume 500 grammes of leaves or more each day in order to grow and survive.

"Climate-induced changes will not only reduce their food resource, but also the nutritional quality and moisture content of leaves. Most recently an 80 percent decline was documented in Queensland's Mulga Lands following the 10-year drought," McAlpine told IPS.

According to the AKF, protecting the existing koala eucalypt forests is also an imperative step towards reducing greenhouse emissions in Australia. Since 1788, nearly 65 percent (116 million hectares) of the koala forests have been cleared and the remaining 35 percent (41 million hectares) remains under threat from land clearing for agriculture, urban development and unsustainable forestry.

As koalas and humans vie for space amidst growing urban and infrastructure development on Australia's eastern seaboard, koalas have been venturing out of their confined eucalyptus forest habitat, often crossing major roads in search of trees or mates.

"Koalas' continuous move into urban areas makes them highly vulnerable to road (accidents) and attacks by dogs. In the rapidly developing region of southeast Queensland, the species has suffered a 60 percent decline in the past decade due to the combination of disease, dog attacks, but mostly collisions with cars," Darryl Jones, deputy director of the Environmental Futures Centre at the Queensland-based Griffith University, told IPS.

Jones, who is the lead author of a recent study aimed at assisting the safe movement of koalas, said, "When forced out of their natural habitat, koalas use all resources available to them including backyard trees, tree-lined road verges and median strips. Retention of these marginal habitats in urban areas is important for koala movement and dispersal." [more]

Climate change compounds rising threats to koala



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