Quantcast

Climate Change Puts Squeeze on Cuddly Koalas

Climate

By Tim Radford

Human-induced climate change promises to make life a lot harder for one of Australia's most charismatic species—the koala.

The herbivorous marsupial (Phascolarctos cinereus), unique to the world's largest island, is rarely seen. It moves slowly, lives high in the canopy on a diet of eucalyptus leaves, sleeps for up to 20 hours a day and yet is known to billions worldwide as the model for a cuddly toy loved by children.

A koala bear and baby find leaves to nibble on. Photo credit: Mathias Appel / Flickr

Its demands are few: a supply of fresh eucalyptus foliage, a little water to drink and somewhere quiet to flourish. But a new study in Global Change Biology suggests that by 2070 much of its native homeland won't provide what it takes to make a home any more.

Potential Range

Natalie Briscoe, an ecologist at the University of Melbourne and colleagues used everything they knew about koalas—behavior, body size, fur depth and physiology—to predict how much energy and water koalas would need to survive at any location. They made the assumption that eucalyptus trees would be available everywhere.

Then they used their knowledge of the animal to make a map of potential koala habitat 60 years from now. And they found the animal's potential range dramatically smaller.

The problem lies not in inexorable global warming—average planetary atmospheric temperatures have risen by 1 C in the last century and the world has pledged to keep the overall rise to lower than 2 C— but in the frequency of extremes of heat and drought. And in a land of extremes, more extremes are on the way.

Dr. Briscoe said:

“Studies of climate change impacts on wildlife have often focused on how changes in average temperature or rainfall will affect species, but our research highlights the importance of thinking about the extreme conditions that will be most stressful for the animals—such as hot, dry periods—and how these may change in the future.

“By developing a better understanding of what controls species distributions now, we are much better placed to forecast how these may shift in the future."

The researchers also correlated all the known koala locations and then matched that data with climate records from the recent past—another way of helping understand what climate change can do to wildlife. Both models predicted that the animal would suffer in the hotter, drier parts of its range.

Rainfall Patterns

The summer of 2013 broke all records for temperature extremes in Australia and researchers expect rainfall patterns to be disrupted and heatwaves and droughts to grow in number and intensity with time.

The challenge for conservationists is to identify those regions where the koala is more likely to survive. Ecologists call these places refugia: in times of stress, a species retreats to a limited range and expands when conditions improve.

“There is a lot of uncertainty when predicting the impacts of climate change on species, particularly when climate change leads to novel weather patterns," Dr. Briscoe said.

“Comparing predictions from different models allows us to more confidently predict the location of havens where koalas could survive in the future."

YOU MIGHT ALSO LIKE

NOAA: World's Worst Coral Bleaching Event to Continue 'With No Signs of Stopping'

Cub of Beloved Grizzly Killed by Car as FWS Plans to Delist Yellowstone Bear

Buzz Kill: How the Pesticide Industry Blocks Bee Protections Nationwide

6 Million Tropical Fish Imported Into U.S. Each Year Are Exposed to Cyanide Poisoning

EcoWatch Daily Newsletter

Pexels

By Brianna Elliott, RD

Vitamin C is a very important nutrient that's abundant in many fruits and vegetables.

Read More Show Less
BLM drill seeders work to restore native grasses after wildfire on the Bowden Hills Wilderness Study Area in southeast Oregon, Dec. 14, 2018. Marcus Johnson / BLM / CC BY 2.0

By Tara Lohan

In 2017 the Thomas fire raged through 281,893 acres in Ventura and Santa Barbara counties, California, leaving in its wake a blackened expanse of land, burned vegetation, and more than 1,000 destroyed buildings.

Read More Show Less
Sponsored
Brogues Cozens-Mcneelance / EyeEm / Getty Images

By Alina Petre, MS, RD

Fruit juice is generally perceived as healthy and far superior to sugary soda.

Read More Show Less
Pexels

By Danielle Nierenberg and Katherine Walla

As the holiday season ramps up for many across the world, Food Tank is highlighting 15 children's books that will introduce young eaters, growers and innovators to the world of food and agriculture. Authors and organizations are working to show children the importance — and fun — of eating healthy, nutritious and delicious food, growing their own produce, and giving food to others in need.

Read More Show Less
Pixabay

By Alina Petre, MS, RD (CA)

Purple cabbage, also referred to as red cabbage, belongs to the Brassica genus of plants. This group includes nutrient-dense vegetables, such as broccoli, Brussels sprouts, and kale.

Read More Show Less