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Planning for an Expanding Ice-Free Antarctica

By Jasmine Lee

Climate change will increase the amount of ice-free land in Antarctica by 25% this century.

Mention Antarctica and nature, and most people think killer whales, seals and penguins. But there is so much more when it comes to biodiversity on this frozen continent. Often overlooked is a large suite of native species only found on the land. This terrestrial biodiversity consists of microbes, moss, lichen, two native plants and a large array of invertebrates including tardigrades, springtails, nematodes and mites. Some of these species occur nowhere else in the world and have developed a range of amazing adaptations to survive.

Antarctica’s terrestrial biodiversity is quite constrained, limited to the small patches of ice-free land that make up less than 1% of the continent. Ice-free areas occur on mountain tops, cliffs or coastal oases, and can vary in size from a couple of square metres to hundreds of square kilometres. Many species are only found in a single patch or region, and some patches may be separated by hundreds of kilometres from their nearest neighbour.

Antarctica has been widely proclaimed as a pristine “nature reserve”. Despite this, Antarctica and its dependent biodiversity are not as well-protected as you might think. Terrestrial biodiversity is at risk from climate change, invasive species and expanding human activity.

Furthermore, the Antarctic protected area network has been labelled as inadequate, unrepresentative and at risk. Conservation planning in the region is often considered behind the rest of the world. While this means there is some ground to make up, it also presents a wonderful opportunity to undertake conservation in the region before the risks materialise.

Antarctica is governed through the Antarctic Treaty System (ATS). Multiple mechanisms exist within the ATS for management of the Antarctic environment. Foremost among these is the Environment Protocol, which is administered by the Committee on Environmental Protection (CEP).

The CEP has identified several priorities to focus on. These include how we deal with the introduction of non-native species, tourism activities, revising the protected area network and understanding and considering the impacts of climate change on the environment. There is no better time than now to contribute research to inform better conservation decisions in the region.

Climate change is already occurring in Antarctica. One of the major barriers to robust conservation decisions is our lack of understanding about potential climate change impacts on biodiversity and environment. We began to fill this gap by determining how climate change might impact ice-free areas by the end of this century.

Our analysis revealed that as ice melts around ice-free areas, more than 17,000 km2 of new ice-free area could emerge around the continent. This is a 25% increase on the current ice-free area. The majority of this (14,000 km2) will be on the Antarctic Peninsula, where the current amount of ice-free area could more than triple by the year 2100.

While the amount of ice-free area will increase, the total number of ice-free patches is projected to actually decrease across the Peninsula. This is because as individual patches expand they will start to merge, leading to an increase in connectivity in the region. The impacts of this could be profound.

The expansion and increasing connectivity will undoubtedly provide new dispersal and colonisation opportunities for some native species. However, it may also enhance the spread of non-native species, some of which are already present.

The opportunities for new species to make it to Antarctica are also likely to increase as the number of scientists and tourists visiting the region grows. Most non-native species reach the continent via ships and planes carrying scientists or tourists.

The expansion of non-native species along the Antarctic Peninsula may lead to competition with native species. Antarctica’s native species, which are currently largely constrained by the availability of water, sunlight and nutrients, may fare poorly if they have to cope with competition for limited space and resources. It’s largely unknown how they will perform. Over longer time periods, this may lead to regional homogenisation and the extinction of some native Antarctic species.

Our work, now published in Nature, was submitted to the annual Antarctic Treaty Consultative Meeting. It was recognised by the CEP as an important piece of research to help inform conservation decision-making in the region. By identifying sites and biogeographic regions that are likely to be heavily impacted by climate change, we can pinpoint sites for increased biosecurity and monitoring. This work will also help to inform the design of a new protected area network for continental Antarctica.

Jasmine Lee is PhD student with CEED. She is based at the University of Queensland.