The future is looking grim for some species of Australian eucalyptus trees, as they feel the impact of more severe heatwaves, droughts and floods.
Researchers from the University of Queensland looked at such effects on more than 100 eucalypt species, finding that some may be wiped out from increasingly extreme weather conditions.
The report was modelled on two temperature scenarios. The first scenario was for an increase of one degree by 2055 and an increase of just over two degrees by 2085.
The second, more extreme scenario, saw an increase of 1.5 and 2.5 degrees in those years respectively.
Professor Clive McAlpine from the University of Queensland says that currently, temperatures are tracking at the extreme end of the range, and without mitigation they will continue to do so.
“We’re basically locked into a warming of 3.5 to four degrees globally by the end of the century unless we can have some very aggressive mitigation to reduce greenhouse gas,” Professor McAlpine said.
The study found that drought appears to be the biggest threat to gum trees, out of all the weather conditions it considered.
“They can’t cope with moisture stress and when you combine heat stress and drought, that is when eucalypts start to die or their canopy deteriorates,” Professor McAlpine said.
The fact that eucalyptus trees have long regeneration times, in combination with the short dispersal distances of their seeds, indicates that they may not be able to keep up with the pace of climate change.
We’re basically locked into a warming of 3.5 to four degrees globally by the end of the century unless we can have some very aggressive mitigation to reduce greenhouse gas.
Professor Clive McAlpine
The research shows that gum trees have moved from central regions of the country toward the east and south coast, and that migration to more moderate conditions could also have a negative effect on native wildlife.
Professor McAlpine says this is especially the case in interior regions of the continent.
“Because those trees provide nectar, they provide resources for wildlife so that those animals that depend on them will not have those resources,” he said.
He also says the local species of eucalypts are the most vulnerable to extinction.
“They’ve only got small populations and they’ve got a very narrow range, so if a major catastrophic event like a drought or a wildfire when through, then they would have difficulty in recovering,” he said.
Planet hurtling toward mass extinction event
However, it is not just gum trees that are under threat from the elements.
Professor Mike Coffin, a marine geophysicist from the University of Tasmania, says the planet is hurtling toward what is called a mass extinction event that could see the end of 75 per cent of the Earth’s species.
Over the past 540 million years, there have been five mass extinction events that were caused by climate fluctuations and volcanic eruptions.
The last such major event was 65 million years ago, when an asteroid slammed in to the Earth, wiping out 76 per cent of total estimated species.
Professor Coffin says that the evidence suggesting we are at the beginning of a sixth mass extinction event is mounting.
“If we continue on the trajectory we’re on, it looks like we’ll reach 75 per cent mass extinction somewhere between 240 and 2,270 years from now,” Professor Coffin said.
He says this future event is different from what has happened in the past because it is manmade.
“This sixth mass extinction, which we appear to be at the start of, is being driven solely by humans. So all the ways that we’re impacting the environment are having an extremely detrimental effect on biodiversity on the whole planet,” he said.
“For example, if a plant becomes extinct, if we drive a plant to extinction, then probably the bees that pollinate that plant will go extinct because they won’t have any food source.”
“I mean, 75 per cent, that as defines a mass extinction, we are facing better than even odds that we will become extinct as well.”
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Story By Whitney Fitzsimmons | Updated Mon 13 Jan 2014, 6:52pm AEDT.
PHOTO: Research shows gum tree migration to more moderate conditions could also have a negative effect on native wildlife. (Flickr: Jar)