High temperatures cause species to spread quickly, says study on accelerating changes in the Antarctic ecosystem in recent years. The frozen continent undergoes major transformations. Rising temperatures in Antarctica over the past decade and reduced ice cover have caused native vegetation to spread rapidly in some regions. The conclusion is contained in the first study on the acceleration of changes in polar ecosystems in recent years, carried out by a group of scientists on the Signy Islands and South Orkneys, in the Antarctic continent.
Since 2009, the spread of the grass deschampsia antarctica and karyophilia colobanthus quitensis has been higher than the sum of the previous 50 years. This period coincides with an accelerated increase in air temperature and a reduction in the number of seals, according to the article published in the scientific portal Current Biology.
The populations of the two plant species have been studied since the 1960s. Research shows that grasses spread at a rate five times faster between 2009 and 2018 than between 1960 and 2009. In the case of caryophylacies, the increase was almost ten times bigger.
In the last decade, the temperature during the Antarctic summer has increased from 0.02 °C to 0.27 °C, despite a strong cooling recorded in 2012.
Professor and lead researcher on the study, Nicoletta Cannone, from the University of Insubria in Como, Italy, says that Antarctica’s terrestrial ecosystems react quickly to changes in climate. “I expected an increase in these plants, but not of this magnitude,” she noted. “We have received multiple evidence that a major shift is taking place in Antarctica.”
The primary factor in these changes is the heating of the air during the summer; and the secondary is the reduction of the seal population on the islands. The reason for the decrease in the number of these animals, which usually move over these plants and crush them, is unknown, but it would probably be associated with changes in food availability and sea conditions.
Analyzes prove the influence of seals on the changes that took place between 1960 and 2009. But, after that period, the biggest transformation factor was the increase in temperature. The warming trend is expected to continue, with the emergence of new melting areas in the coming decades.
The greater presence of these plant species can cause changes in the acidity of the soil, in the bacteria and fungi found in it and in the way organic matter decomposes. Professor Cannone explains that changes in soil chemistry, in addition to the degradation of permafrost, can trigger serial changes that could affect all components of terrestrial ecosystems in the region.
These plants are able to perform photosynthesis in sub-zero temperatures and with snow, and to reproduce quickly even in adverse weather conditions.
“This is the first evidence in Antarctica of accelerated responses of ecosystems to global warming, in line with similar observations made in the northern hemisphere,” the scientists say in the study.
The researchers say the findings observed on Signy Island are representative of the processes taking place in the region as a whole. “Our findings support the hypothesis that warming will trigger significant changes in these fragile Antarctic ecosystems,” the authors said.
