For the first time, scientists have begun study the effects of global warming on plant species morphology. University of Adelaide researchers have found that some Australian plants are narrowing their leaves in response to changes in climate. Lead author of the paper, Dr. Greg Guerin, says, “Climate change is often discussed in terms of future impacts, but changes in temperature over recent decades have already been ecologically significant.”
Scientists gathered historical and contemporary specimens from the State herbarium, some dating back to the 1880’s. Focusing on narrow-leaf Hopbushes from Flinder’s Range, the largest mountain range in Southern Australia, research concluded that “leaf width…was negatively correlated with latitude regionally, and leaf area was negatively correlated with altitude locally.“ Researchers predicted, “…given within-species variation along a climate gradient, a morphological shift should have occurred over time due to climate change.”
That is to say, according to the study posted on Biology Letters today, their hypothesis was proven correct. “We conclude that leaf width is linked to maximum temperature regionally (latitude gradient) and leaf area to minimum temperature locally (altitude gradient).“ Regardless of the researcher’s prediction of the change in adaptation, the results of the study have significant implications in terms of projecting the rapidity of environmental responses to global warming.
The University of Adelaide website says the study revealed a “2mm decrease in leaf width (within a total range of 1-9mm) over 127 years across the region.” Because the temperature in Flinder’s Range has been increasing quickly in recent decades (rising 1.2 degrees Celsius between 1950 and 2005) and has a consistently low amount of rainfall, scientists were able to link changing plant morphology and climate change. The lack of rainfall assisted in isolating the temperature of the species’ climate as directly related to growth and morphology.
According to Dr. Guerin, “Climate change is driving adaptive shifts within plant species and leaf shape has demonstrated adaptive significance in relation to climate.” The authors of the study believe “[this] data indicate[s] a morphological shift consistent with a direct response to climate change and could inform provenance selection for restoration with further investigation of the genetic basis and adaptive significance of observed variation.”
Dr. Guerin, a postdoctoral fellow with the University of Adelaide’s School of Earth and Environmental Sciences, says some plants in Australia are more resilient than others. Dr. Geurin says some species rely heavily on migrating to more friendly climates—problematic in an environment fragmented by human activity. He continues to illustrate the significance of this adaptation, saying, “It’s important to understand how plants cope with changing climates, because species that are more adaptive to change may be good candidates for environmental restoration efforts.”