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Taking the heat: The quoll, a small predatory marsupial, is one of the species threatened by climate change, says the WWF. Credit: Bruce Thompson / WWF SYDNEY: Native Australian animals are increasingly at risk of extinction due to climate change, while invasive species could conversely benefit from rising temperatures, says a WWF report. Species at threat from sweltering temperatures and lower rainfall include rock wallabies, the rabbit-eared bilby (Macrotis lagotis) and native cat-like predators called quolls, said the report released by the Australian wing of the conservation group. These animals are already battling bushfires, habitat loss and introduced predators such as the cane toad and fox. Old threats in new places "The early signs are that climate change is likely to make all of the existing threats to species worse," said the report, released Tuesday. "As humans respond to changes in climate, agricultural expansion into parts of Australia, such as the northern savannahs, that are predicted to have more rainfall, will mean old threats to species in new places." WWF species program leader Tammie Matson, based in Sydney, said the country already has the worst rate of mammal extinction in the world, with close to 40 per cent of the global mammal extinctions in the last 200 years. Scientists have predicted that by 2070 average Australian temperatures could increase by as much as 1.8 to 3.4°C, with severe impacts for the already parched landmass. The report, however, warns that invasive weeds and pests are able to colonise new habitats quickly and even favoured the changing conditions. "The threat posed by invasive species could increase with climate change," it said. "Pests such as the cane toad will thrive in warmer conditions and move into new areas." Whilst the cane toad may thrive, climate change will not favour other amphibians. According to climate modeling done for the Australian Greenhouse Office, in Canberra, the climatic habitats of several Western Australian frog species, including the white-bellied frog (Geocrinia alba) and sunset frog (Spicospina flammocaerulea), are predicted to disappear with an increase in average annual temperatures of just 0.5°C. Turtle declines Many species are already at risk from rising temperatures, including marine turtles. Australian waters are home to six of the seven species of marine turtles, with one species, the flatback turtle (Natator depressus), nesting exclusively on Australian shores. Turtle eggs are extremely vulnerable to temperature, and the sand at nesting-depth on some beaches has already risen above the maximum incubation temperature of 32°C, with lethal consequences. A warming climate also threatens to skew the sex ratio of hatchlings, as the incubation temperature determines the sex of the turtles. Warmer sands produce more females, and so even small temperature increases are generating gender biases detrimental to breeding. "Marine turtles have responded to climate change in the past. However, marine turtle populations are already rapidly declining, with many being perilously close to extinction due to human induced threats," states the report. "Combined with the added pressure of accelerated global warming, many marine turtle populations are unlikely to avoid extinction long enough to adapt." Cyclones and fires Rising temperatures are not the only negative effect of climate change, however. More frequent and powerful cyclones could threaten tree-dwelling mammals such as tree kangaroos too. Furthermore, the report warns that in south-east Australia, the frequency of very high and extreme fire danger days is likely to rise up to 70 per cent by 2050, impacting species such as the black cockatoo (Calyptorhynchus lathami) and quolls. Southeast Australia is already recognised as one of the most fire-prone regions of the world. "With the number of threats to our species increasing, it is up to us to do our bit by reducing our own carbon emissions," said Matson. "Small actions taken in your everyday life is all it takes to make a big difference. It's as simple as switching off your lights." with AFP Readers' comments
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Australian species: increasing climate threat
It's good to see the WWF highlighting the deadly impact invasive species have on Australia's native plants and animals, especially in connection to the growing threats many species are facing under climate change.
Speaking at the Invasive Species Council's AGM last year, author and biologist Tim Low warned that weeds, feral animals and invasive organisms will be the big winners under climate change.
He said many species will lose out but the greatest impact is going to come from those species that are favoured by climate change.
Tim said that if we don’t focus on these we are going to miss out on comprehending a whole lot of what is going to go on ecologically.
Weeds do incredibly well in the wake of fires, drought, cyclones and floods, all of which are predicted to increase as the planet’s climate heats up.
Tim said that if we look at the 20 worst weeds in Australia nearly all of them are known to benefit from dramatic, extreme climatic events.
He said Victoria’s smaller, fragmented nature reserves, which are often surrounded by farmland, will be particularly vulnerable to weed invasions as species are forced to migrate further south under climate change.
While weeds will have no problem moving across much of the state’s agricultural land, many native species will not fare so well.
“The fast get faster, and as we know they are so often weeds,” he said.
Climate change extinctions
Warning of worse to come Tim said the world had seen its first “climate change extinctions” with the disappearance of 70 species of harlequin frogs from the mountains of Central and South America over the past ten years.
“These are being described as the first ‘climate change extinctions’. But it’s actually an invasive organism that has been the agent of extinction. The frogs that went extinct were not under any stress from climate change directly but from an invasive organism.”
Scientists believe changing climatic conditions increased cloud cover in the frogs’ mountain habitat, creating ideal conditions for the spread of the disease-causing chytrid fungus.
Tim said the same thing could happen in the mountains of Tasmania and Victoria.
The Invasive Species Council is a member of the Victoria Naturally alliance, which co-hosted Tim’s talk.
You can find out more about he alliance by going to www.victorianaturally.org.au
For more on the Invasive Species Council go to www.invasives.org.au.
Weeds and ferals in Victoria
• There are some 1000 weed and at least 250 pest animal species in Victoria.
• Most animal extinctions in Victoria, including bettongs and the Tasmanian Pademelon, have been blamed on foxes and other invasive pests.
• Cats, rabbits and trout continue to threaten the survival of rare and endangered species.
• Deer are multiplying rapidly in Victoria, representing a growing threat to biodiversity.
• Our marine habitats are also under pressure, with more than 100 marine species introduced to Port Phillip Bay, severely impacting on native species, ecosystems and fisheries.
• Submissions from community organisations to the State Government’s Land and Biodiversity White Paper inquiry overwhelmingly identified weeds as one of the biggest threats to Victoria’s natural environment.
Regards, John Sampson - Victoria Naturally Alliance.