New research shows that climate change is hitting eucalypts as climate change increasingly creates a mismatch between forest trees and their home environments.
In a paper published last week in the journal Global Change Biology, lead author Dr. John Drake from the Hawkesbury Institute for the Environment at the University of Western Sydney and his colleagues report that as temperatures increase, eucalypts growing in already warm locations are likely to be more negatively affected by increased warming compared to cooler climate eucalypts that experience increased warming in their home environments.
The research team conducted an experiment using 21 seed varieties grown in a series of climate-controlled glasshouses to test their predictions. The researchers compared those home-grown plants to those grown with an additional warming treatment of 3.5 degrees Celsius.
To test their predictions, the research team conducted a climate shift experiment using 21 seed varieties grown in a series of climate-controlled glasshouses that approximated summer conditions occurring in the seeds’ areas of origin. The researchers compared these home-grown plants to those grown with an additional warming treatment of 3.5 degrees C.
The cool-origin eucalypts responded to the higher temperatures with an increase in photosynthetic activity leading to enhanced growth of 20 to 60 per cent. However, those originating in warm areas responded to increased temperatures with a reduction in photosynthetic capacity and total leaf area, leading to a reduced growth of 10 per cent.
“What we can see is that increased warming in already warm places is likely to affect eucalypt trees more adversely than increased warming in cool places,” Dr Drake says.
The eucalypt research results have wider implications for the survival of other warm-origin plants and trees, says Professor Mark Tjoelker, a UWS researcher who worked on the project with Dr. Drake, which will be threatened even further by drought in warm areas.