Researchers from the University of Adelaide examined specimens of narrow-leaf hopbush (Dodonaea viscosa, subspecies angustissima), a woody shrub with papery red seed capsules that were used by early Australian colonists to brew beer. They found that between the 1880s and the present, leaves have narrowed by an average of 0.08 inches (2 millimeters).

 

"Climate change is often discussed in terms of future impacts, but changes in temperature over recent decades have already been ecologically significant," study researcher Greg Guerin, a postdoctoral researcher at the University of Adelaide, said in a statement. "Climate change is driving adaptive shifts within plant species and leaf shape has demonstrated adaptive significance in relation to climate."

 

Plants from warmer latitudes typically have narrower leaves, Guerin said. Climate change also shrinks animal life, research has shown.

In the Flinders Ranges of South Australia, rainfall has stayed fairly constant while maximum temperatures have increased by 0.7 degrees Fahrenheit (1.2 degrees Celsius) since 1950. Guerin and his colleagues looked at hopbush specimens dating back as far as the 1880s.

"Our results indicate that leaf width is closely linked to maximum temperatures," Guerin said. The results were detailed online July 3 in the in the journal Biology Letters.