Bulletin

Issue: May/June 2007

Research

Global climate change – turning up the heat on the high plains

Scientists from La Trobe University’s Research Centre for Applied Alpine Ecology are collaborating in a multinational study to evaluate how global warming is likely to affect cold climate ecosystems in Arctic and Alpine regions around the world.

The Australian end of the work focuses on experiments in Victoria’s high country. Scientists plan to feed data into computer models that will help predict how cold climate plants and animals will respond to rising temperatures – and whether they have the genetic capacity to adapt.

The experiments are a collaborative, multidisciplinary effort involving three specialist research groups from two universities – La Trobe University’s Research Centre for Applied Alpine Ecology, the University of Melbourne’s Centre for Environmental Stress and Adaptation Research (CESAR), formerly at La Trobe, the Environmental Science Laboratory from the University of Melbourne’s School of Botany – and the CSIRO, with funding from the Australian Research Council, the Victorian Department of Sustainability and Environment, ES Link and Parks Victoria.

Early results from the Victorian research are being compared with data from similar experiments in the northern hemisphere’s collaborative International Tundra Experiment (ITEX), which encompasses more than 11 countries including Sweden, Norway, Finland, Russia, Canada, Tibet and the United States.

By incorporating their Victorian research into this major ITEX project, Australian scientists have ensured that the project now sweeps both hemispheres – making it the world’s first truly global experiment to replicate the effects of climate change in equivalent tundra across the globe.

The research combines ITEX field protocols for passive warming experiments, genetic studies and ecological modelling techniques to investigate the effects of rising temperatures on cold climate plants and soils – as well as some animal species, including the endangered mountain pygmy possum. The field sites are in open heathland on the Bogong High Plains, where, during the snow-free period, scientists monitor ecological responses to elevated temperatures in 40 hexagonal enclosures known as Open-Topped Chambers (OTCs).

The chambers are set out at four sites around September- October each year when the first snows begin to melt – two in vegetation burned during the 2003 bushfires, and two in unburnt vegetation – and removed again in early June with the first snowfalls.

The OTCs function as small greenhouses, raising ambient temperatures inside by about 1.5 degrees centigrade, mimicking the anticipated increase in temperature over the next twenty years or more.

With temperatures elevated inside the chambers, the snowgrasses, shrubs and flowering herbs of the Bogong High Plains get a taste of things to come. And scientists monitor every response: the emergence of a plant’s first leaf, its first flower bud, the first flower opening, its seeding and growth, the behaviour of the soils, even changes in plant litter.

By monitoring what happens inside the chambers and comparing it with what happens outside, they hope to gain a better understanding of the likely consequences of global warming for coldclimate ecosystems. They seek to find out, through warming experiments and genetic and modelling, how individual plant species respond, how the responses are reflected in plant populations and patterns across the landscape, and to what degree species can genetically adapt.

While there is some evidence that tundra plants have high levels of genetic variation and thus an inherent ability to cope with climate change by adaptation, scientists need to assess variations in genetic traits that are specifically caused by climate change.

By using genetic markers to assess gene flow and studying variations in specific traits such as leaf shape, under different conditions, they can begin to assess the adaptability of selected plant species – which may then act as early warning signals that climate change is affecting the surrounding alpine system. This potentially provides an ecological management tool for mediating climate change.

The three principal components of the Australian project are closely integrated. Field studies are managed by La Trobe’s Research Centre for Applied Alpine Ecology, and the genetic and modelling studies by the University of Melbourne’s CESAR and its Environmental Science Laboratory, with additional ecological support from the CSIRO.

The warming experiments began in 2003. The first results were reported to the 2006 ITEX conference in Miami and further results to the 2007 conference in Australia.