Challenge and opportunity as climate change impacts the icy continent
Antarctica is being impacted by climate change, invasive species and an expanding human footprint
Ice-free areas, home to nearly all Antarctic terrestrial biodiversity, are projected to dramatically expand by 2100 with potentially severe consequences for native species
There is no better time than now to be doing research to feed into Antarctic policy
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, not in the sea. This terrestrial biodiversity consists of microbes, moss, lichen, two native plants and a large array of invertebrates (including tardigrades, springtails, nematodes, rotifers and mites). Some of these species occur nowhere else in the world. Living in an extreme environment means these species use a range of amazing adaptations to survive including, for example, dehydrating (anhydrobiosis) to survive long periods without water. And, when suitable environmental conditions come along, many species increase growth or activity rates.
Antarctica’s terrestrial biodiversity is simply amazing but it’s also 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. The large amount of regional endemism within Antarctic taxa (ie, many species are only found in a single patch or region) reflects the isolated nature of these ice-free areas. Some patches may be separated by hundreds of kilometres from their nearest neighbour. The important question is: Are these ice-free patches under threat? Antarctica has been widely proclaimed as pristine and a “nature reserve devoted to peace and science”. Despite this, Antarctica and its dependant biodiversity is not as well protected as you might think. In fact, terrestrial biodiversity is at risk from climate change, invasive species, and expanding human activity (scientists and tourists). Furthermore, the Antarctic protected area network has been labelled as inadequate, unrepresentative and at risk (see Decision Point # 90). Conservation planning in the region is often considered behind the rest of the world. So, 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.
Making decisions for Antarctica
Policy and decision-making operate differently in Antarctica. The region is governed through the Antarctic Treaty System (ATS). While it can be challenging to achieve consensus amongst signatory countries on any Antarctic decision, multiple mechanisms exist within the ATS purely for management of the Antarctic environment. Foremost amongst these is the Environment Protocol, which is administered by the Committee on Environmental Protection (CEP). The Protocol is the international agreement that establishes the framework for comprehensive protection of the Antarctic environment. The CEP has identified several priorities to focus on in the next five years. These include how do we deal with the introduction of non-native species, tourism activities, revising the protected area network and understanding and considering impacts of climate change on the environment? Given this willingness to engage with these issues, there is no better time than now to contribute research to inform better conservation decisions in the region.
Planning for climate change
Climate change is already happening in Antarctica, parts of it are some of the most rapidly warming places on the planet. 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, over 17,000 km2 of new ice-free area could emerge around the continent (Lee et al, 2017). 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 change in habitat on biodiversity, therefore, 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. Currently, Antarctica’s greatest protection against non-native species is its extremely harsh weather and climate. Climate change is expected to take some of the edge off this harshness by making the weather warmer and milder. This will allow the establishment of new non-native species that previously wouldn’t have had a chance. And 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, with many species arriving in food or cargo shipments.
A new playing field
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 abiotic factors (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 extinction of some native Antarctic species. And, as climate change continues, the impacts we describe for the Peninsula are likely to become more prominent across the rest of the continent. Our work, now published in the journal Nature, was submitted as an Information Paper to the annual Antarctic Treaty Consultative Meeting (held in Beijing earlier this year). 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.
More info: Jasmine Lee firstname.lastname@example.org
Lee JR, B Raymond, TJ Bracegirdle, I Chadès, RA Fuller, JD Shaw & A Terauds (2017). Climate change drives expansion of Antarctic ice-free habitat. Nature 547, 49-54. http://dx.doi.org/10.1038/nature22996