Chironomid Aliens in Antarctica

An alien species introduced by humans to Antarctica in the 1960s has not only survived, but thrived in the cold, harsh conditions. Scientists from British Antarctic Survey (BAS) have discovered millions of larvae from a tiny fly (a chironomid midge) living in the soil on Signy Island.

This non-native species of the fly was taken from South Georgia and inadvertently introduced to Signy Island (a much colder island within the Antarctic region) as part of a scientific experiment to see whether plant transplants would survive. The larvae of the fly survived in the soil on the island, whereas most plants that were introduced at the same time did not (those that did survive were removed). A very small worm (an enchytraeid) that was also introduced at the same time has survived in only very small numbers.

Signy Island 

Source: British Antarctic Survey

The fly is now well established and there are up to 410,000 fly larvae per square metre in the area around the introduction site. The adult fly has only remnant wings and cannot fly; but the species has spread up to 220m away from the introduction site. Since this discovery scientists have been monitoring the significant spread of the alien species in order to gain a better understanding of how such species affect the native ecosystem.

Over the last two centuries human activities have led to the accidental introduction and establishment on land of many alien species of vertebrate, invertebrate and plant, particularly to the sub-Antarctic islands. These introductions include organisms with functions that are poorly or not represented in the native ecosystems, and in some cases have led to drastic alterations in ecosystem structure and function.

Source: British Antarctic Survey
Presentation summary for the IPY Science Conference 2010 in Oslo by Dr. Kevin Hughes and Professor Pete Convey