14 DAY TRIAL // The effects of global warming extend far beyond warming the world's waters, melting polar ice caps and extinguishing countless species. Australian researchers found in a new study that the leaves of certain plant species are getting narrower.
The research, led by investigators at the University of Adelaide, revealed that recent climate changes sweeping through the continent are responsible for this effect. According to the team, this is the first study of this kind ever conducted.
Other than studying the localized effects of global warming, the new paper also draws attention to the fact that plant adaptation to global warming occurs right now. Previously, scientists believed that at least a few more decades would pass until ecosystems began adapting to the new conditions.
Details of the investigation were published in the July 4 online issue of the esteemed Royal Society journal Biology Letters. The work was focused on the plant Narrow-leaf Hopbush (Dodonaea viscosa subsp. Angustissima).
Experts had access to herbarium specimens of the plant spanning from the 1880s to present day. This enabled them to conduct a mid-term analysis of the plant's evolution, and to determine that the width of its leaves is consistently getting thinner.
The study showed that maximum temperatures in South Australia – where the work was conducted – increased by 1.2 degrees Celsius between 1950 and 2005. Over the past 127 years, the width of Narrow-leaf Hopbush leaves decreased by an average of 2 millimeters.
“Climate change is often discussed in terms of future impacts, but changes in temperature over recent decades have already been ecologically significant,” UA School of Earth and Environmental Sciences postdoctoral fellow Dr. Greg Guerin explains.
“Climate change is driving adaptive shifts within plant species and leaf shape has demonstrated adaptive significance in relation to climate. Our results indicate that leaf width is closely linked to maximum temperatures, and plants from warmer latitudes typically have narrower leaves,” he adds.
“In the case of Narrow-leaf Hopbush, we can significantly link the changes in leaf width to changes in climate,” says the expert, who was also the lead author of the new study, ScienceDaily reports.
As a general rule, when temperatures increase, plants tend to shrink the surface area of their leaves, in order to minimize evaporation, and prevent moisture loss. This is why the cactus, for example, has thorn-like leaves now – it has adapted to growing in the desert.