According to the first study that has shown changes in fragile polar ecosystems, Antarctica’s two native flowering plants are expanding rapidly.
According to researchers from Signy Island in South Orkney Islands the 2009 increase in plants was greater than the 50 years before that. This is due to rapidly rising air temperatures, and a decrease of fur seals.
Populations of Antarctic hairgrassDeschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensisSince 1960, scientists have studied the island’s hairgrass. Research has shown that hairgrass spread five times faster than it did between 1960 and 2009. The paper found that pearlwort experienced a nearly ten-fold increase in growth between 2009 and 2018.
Despite the strong cooling of 2012, summer temperature has risen from +0.02C and +0.27C in the past decade.
These climatic inputs are quickly reacted to by Antarctic terrestrial ecosystems, according to Prof Nicoletta Cannone from the University of Insubria, Como, Italy. I expected an increase in these plants, but not to this extent. Multiple evidences are being presented that Antarctica is experiencing major changes.
According to the study which has one of the longest records on changes in Antarctica’s vegetation, the main driver of change is the warmer summer air. The island has fewer fur seals, which trample on the plants. Although it is not clear why seal numbers have declined, it is likely that changes in food availability and sea conditions are to blame.
Analysis revealed that fur seals had an influence on changes between 1960 and 2009, while temperature rise was the main driver between 2009-2018.
Warming trends are expected and will continue. Signy Island is one example of the many processes that are occurring in the region. Researchers believe that future warming will cause significant changes to these fragile Antarctic ecosystems. Our findings support this hypothesis. The paper was signed by the authorPublished in Current Biology.
These species will spread and cause changes in soil acidity and bacteria and fungi, as well the way organic matter is decomposed. Cannone said that soil chemistry changes and permafrost degradation will create a cascade effect that will impact all components of terrestrial ecosystems.
They can photosynthesise in snowy conditions and temperatures below 0C. They can reproduce quickly and in harsh climates but are not able to compete with other non-native plant species. Researchers warn that while warming may be beneficial to some native species when it is done in isolation, it increases the risk for the establishment of non native species that could outcompete native species. This could lead to irreversible wildlife decline.
Signy Island was colonized in 2018 by Poa annua, an aggressive grass species that is commonly used on golf courses. Cannone said that invading alien species can cause dramatic loss of Antarctica’s native biodiversity. This was a result of millions of years worth of evolution and survival. The effects of vegetation change on the terrestrial biota will be a domino effect.
The Antarctic experienced warming events in the mid-Pliocene that allowed for the spontaneous migration of species from South America into Antarctica. Scientists warn that current levels of warming could have already triggered such a migration of mosses and lichens, as well as vascular plants, and invertebrates. This was facilitated by increasing levels of tourism in Antarctica.
Dr Kevin Newsham (a British Antarctic Survey terrestrial ecologist) said that the study showed that more species could be established in Antarctica as the climate warms. However, there could be increased ecosystem risks from this.
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