Sunday, January 12, 2014

Climate change set to give us a home without the gumtrees

Lucy Cormack
The Age, January 13, 2014 

Australia's standing as the home among the gumtrees could be challenged, with increased climate stress causing extensive change to Australia's eucalypt ecosystems.

A study by the National Environmental Research Program's Environmental Decisions Hub has found that climate stress on eucalypts will mean many of Australia's 750 species will struggle to cope with climate change.

''Those that will be most affected are the Eucalyptus and Corymbia species in the central desert and open woodlands area,'' said author Nathalie Butt of the NERP Environmental Decisions Hub and the University of Queensland.

The study found that ''under the mid-range climate scenario, these species will lose 20 per cent of their climate space, and twice that under the extreme scenario''.

The mid-range scenario suggests that ''temperatures will increase by more than 1C by 2055 and by more than 2C by 2085. For the extreme scenario temperatures will increase by more than 1.5C and 2.5C respectively'', Dr Butt said. She said there is additional concern for the impact these conditions will have on wildlife in such areas. ''Trees are habitats and food sources. So this will have a cascade effect on birds, bats and invertebrates that are reliant on eucalypt, and it will affect pollinators as well,'' she said.

While carbon dioxide alone may contribute to additional plant growth, rising heat extremes and rainfall shortages could counter any gains. ''No matter how much carbon dioxide there is, there will become a point where water limitation will override that. What the climate projections are suggesting is that the seasonality of rainfall will increase so there will be longer dry seasons,'' Dr Butt said.

One expected change is the shift of open woodland areas to savannah-like conditions, with more grassland.

As eucalypt ecosystems adjust to cope with warmer and drier conditions it is predicted that trees may shift their ranges towards the coast where growing conditions are more favourable, Dr Butt said.

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