Antarctica Braces for Influx of Invasive Species

Posted by Claire Christian of Antarctic and Southern Ocean Coalition in Ocean Views on January 7, 2013

Antarctica and the Southern Ocean may seem very far away from civilization, but they are at great risk of losing their unique qualities due to human activities. Warmer temperatures and human visitation are increasing the likelihood that invasive species can take up residence in the Antarctic, and potentially cause major changes. Two studies have found evidence of invasions both on land (from a midge) and at sea (from crabs). The remoteness of the Antarctic can no longer protect it from potentially destructive invaders. Forget about The Thing – the scariest alien invaders in the Antarctic come from our own planet.

Concern about a possible crab invasion of Antarctica began in 2007, when ecologist Sven Thatje saw a few king crabs on the outer continental slope of the Antarctic Peninsula. Their presence raised immediate alarms. Unlike more famous invaders like lionfish or brown tree snakes, crabs have yet to gain notoriety as ecosystem destroyers. But in the Antarctic, cold water has long kept out crustaceans like crabs and lobsters, which cannot survive at temperatures below 1°C (just under 34°F). The result is that many seafloor creatures in the Southern Ocean today have not evolved the same defenses against crushing claws as species in other regions. So the discovery of Neolithodes yaldwyni, a species of king crab, by a submersible surveying shallower areas closer to the Antarctic Peninsula (one of the fastest warming areas in the world) was unwelcome news. This indicates that the crabs are more firmly established, and have become truly invasive. The researchers who discovered the crabs estimate that there are 1.5 million crabs in the Palmer Deep. As warming of ocean water increases, the range of these crabs will expand further.

On land, researchers have also recently found evidence of unwelcome invaders that could make life very difficult for native species. This time, the invading species is the midge Eretmoptera murphyi, and they appear to be speeding up the rate at which decay occurs in Antarctic soil. The midge hails from the sub-Antarctic South Georgia Island, but the ecosystem on that island is very different from the one on the Antarctic Peninsula, where the midge has now established itself. Decay in peninsular soil is “not very active,” according to Peter Convey, one of the scientists who discovered the presence of the midge, so the insect will introduce a new process to the ecosystem. Unfortunately for the peninsula, though its ecosystem is composed of different species, the midge can still survive in its climate. Although one tiny insect might not seem to be very disruptive on a continent without many terrestrial species, it has been well established that many Antarctic species are highly vulnerable to disturbances, so introducing a new ecosystem process could introduce a major shift.

Unlike the crab invasion, however, the midge invasion and other invasions of land species can be slowed or prevented by following strict rules that reduce the possibility that species can tag along with humans visiting different areas of the Antarctic. Even so, it’s virtually impossible to eliminate the transfer of invasive species entirely. In the sea, it will be very difficult to slow down the global warming that allows new species to colonize the Southern Ocean, so we will have to wait and see if a crustacean-generated apocalypse occurs for Antarctica’s unique seafloor communities. The presence of these invaders, it seems, only further indicates that humans have impacted the environment in virtually every place on earth, with possibly disastrous results for the world’s biodiversity.

The growing problem of invasive species is yet another reason to designate marine protected areas (MPAs) in Antarctica as soon as possible. By restricting some types of human activities, MPAs provide reference areas that can be compared with areas where activities aren’t restricted, thus helping scientists understand what ecosystem changes are caused by invasive species or climate change versus those caused by fishing or pollution. MPAs can also minimize some human-induced stressors on threatened ecosystems. Unfortunately, MPAs can’t keep king crabs out, but they can help scientists obtain a better grasp on the seismic changes taking place in the frozen south.

In Your Words...

  • “Parks Canada and Canadians have benefited from the partnership to have on-the-ground Hot Spots crews, and we would be happy to work with a crew in the future at one of our many national parks and national historic sites that are in need of invasive plant management.”

    Brian Reader, Species at Risk Manager, Parks Canada

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    Brian Reader, Species at Risk Manager, Parks Canada

  • "We had a great hike at Kenna Cartwright Park. The kids built a snowman and we all enjoyed the views. The outreach worker showed us some plants that don't belong in the park, gave us info about them and what to do about them, and gave us all some cool gifts from the Invasive Plant Council. Thank you!"

    Susan Hammond, Kamloops Young Naturalist Club

  • “Working with the Hot Spots crew in Saanich in 2010, we practiced different methods to treat knotweed with glyphosate using the injection gun on several sites. With these skills I was able to implement Saanich's first knotweed eradication pesticide treatment program for private properties.”

    Donna Wong, Environmental Stewardship Officer, District of Saanich

  • “I am impressed with the coverage of the GIS mapping data now available. I will be developing an Invasive Species Management Plan for Pacific Spirit over the next several years and these maps will help as a coarse indication of current conditions, and in guiding initial inventory and monitoring efforts.”

    Markus Merkens, Pacific Spirit Park area manager, Metro Vancouver

  • “Thank you for orchestrating access to the Hot Spots crew for GINPR.  This crew allowed us to move the restoration project on Princess Margaret ahead by months if not by years.”

    Wayne Bourque, Superintendent of Gulf Islands National Park Reserve, Parks Canada

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