Bulletin

Issue: May/June 2007

Research

Staring down the crisis of our times

La Trobe University ecologist Dr Carl-Henrik Wahren is happiest working in a snap-frozen, wintry landscape, contemplating the state of the biosphere.

This Scandinavian-born Australian scientist spends months, and sometimes years at a stretch in the treeless, icy tundra of the world’s Alpine and Arctic regions engaged in frontline ecoscience.

On the Bogong High Plains in the Victorian Alps he and his fellow biologists are staring down the existential crisis of our times: global climate change.

While research into the effects of climate change has been under way for many years in Australia’s Alpine regions, the Victorian work represents a new frontier: where scientists can simultaneously interrogate the global warming phenomenon in two hemispheres. (See main story.) As the scientist primarily responsible for bringing Australian research on board with ITEX study sites overseas, Dr Wahren’s contribution has been pivotal.

In 2001 he was monitoring the effects of climate change on plants and soils in Alaska using open-topped temperature controlled chambers. He was struck by the familiarity of the terrain.

‘The animals and plant species are different, but the size of the plants, their distribution and dominant growth forms, even some plant families, are the same or very similar,’ Dr Wahren says. ‘These similarities reflect similarities in climate, especially micro-climate – low temperatures, wind, snow, and a lack of trees, while herbs and shrubs dominate: a trend that continues with increasing latitude and altitude.’

That sense of environmental deja vu led to the Australian work. ‘I wanted this experiment extended to the southern hemisphere, making it truly global,’ he says.

The following year, supported by Warwick Papst from La Trobe’s Research Centre for Alpine Ecology, La Trobe botanist Dr John Morgan, Dr Dick Williams from CSIRO and a group of third year biological sciences undergraduates, Dr Wahren set up 40 open-topped chambers on the Bogong High Plains in the Victorian Alps.

Working closely with ecological modellers, climatologists, geneticists and soil scientists from the University of Melbourne and Victoria’s Department of Sustainability and Environment, and other international scientists, La Trobe scientists aim to bring many novel strands of research towards one common goal: an understanding of how land, oceans, and atmosphere interact and influence the global climate system.

‘This is ecosystem research which is looking at a landscape and trying to understand not only how it is likely to respond to a particular threat, such as an increase in temperature, but how that response helps us to understand how a landscape functions,’ says Dr Wahren. ‘We can then apply that understanding to other areas – such as agricultural lands.’

‘With decreased rainfall predicted for Australia’s south-east, and given that most of our water comes from the high country, we are likely to see changes in high country ecosystems which can impact on the lowlands.

‘If we can predict how these landscapes are likely to respond, we may be able to do something about it.’

The research in the Alps has three components: field studies, involving the passive warming experiments and collecting, storing and interpreting response data; genetic experiments in which key species are cross-planted along environmental gradients to measure their ability to adapt; and ecological modelling, which will result in computerised ‘population’ and ‘habitat’ models for translating the data from the warming and genetic studies into predictors for climate change across the landscape.

While scientists caution against interpreting results too early, the research is already breaking new ground, with evidence that some alpine plant species can adapt genetically to climate change.

These findings – and other new evidence revealing the low genetic diversity of the mountain pygmy possum – were reported to the ITEX gathering in Melbourne earlier this year.

Dr Wahren says it was exciting for researchers to see early results from Australia showing similar trends to those they’ve seen in the north.

‘This is why experiments involving both hemispheres are necessary, because it leads to a better understanding of how the biosphere is responding, and likely to respond, to a changing climate.

He says the experiment adopts largely a systems approach, popularised through the Gaia metaphor.

‘Atmospheric scientists have long used it, recognising the tightly coupled links between atmosphere, oceans and land. Ecologists have been a little slow to adopt this method, but they’ve recognised the need, because what happens in one part of the globe often affects other parts.’

Dr John Morgan, of La Trobe’s Department of Botany, endorses the global importance of the project.

‘We are at the forefront of climate change research in Australia, and important contributors to the international effort to understand potential changes in alpine and arctic areas. Ecological research like this will be vital to understanding how the natural world will respond to global warming.’