An insect invasion of Antarctica: the past, present and future distribution of Eretmoptera murphyi (Diptera, Chironomidae) on Signy Island
2020
Bartlett, Jesamine C. | Convey, P. (Pete) | Pertierra, Luis R. | Hayward, Scott A. L.
Rising human activity in Antarctica, combined with continued warming of the polar climate, means the risk of non‐native terrestrial species colonising and establishing in its biodiversity‐ and nutrient‐poor ecosystems is increasing. Of the five non‐native invertebrate species currently in terrestrial Antarctica, the flightless midge Eretmoptera murphyi (Schaeffer, The Museum of the Brooklyn Institute of Arts and Sciences 2:90–94, 1914) is perhaps the most persistent insect invader. Accidentally introduced to Signy Island (60°S) in the 1960s from sub‐Antarctic South Georgia (54°S), E. murphyi has steadily increased its distribution, however, its status has not been reassessed for a decade. Here, we update the distribution of E. murphyi on Signy, specifically assessing whether footpaths to regularly visited research sites represent dispersal corridors. Our findings show that both the abundance and range of E. murphyi have increased significantly since 2009, particularly along paths leading away from the original introduction site, and that the species is now on the cusp of moving into new valley systems. We identify a moderate association with soil/substrate and vegetation types and build Maximum Entropy (MaxEnt) models to predict areas of the island that may be at highest risk of future colonisation. As a detritivore with no competitors or predators, E. murphyi may have a major impact. For example, accelerating nutrient cycling which may have wider impacts on all levels of biodiversity. This study highlights the need for an assessment of current biosecurity protocols applied within the Antarctic Treaty system, as well as the need for systematic regular monitoring of introduced and invasive species in Antarctica.
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