Sammendrag
The nutrient-poor soils of Antarctica are sensitive to change. Recent increases in the number of anthropogenic
introductions mean that understanding the impact of non-native species on Antarctic soils is pertinent, and
essential for developing future risk assessments and management strategies. Through comparative baseline assessments of vegetation, microbes, soil chemistry, substrate composition and micro-arthropod abundance, this
study explored if there are detectable terrestrial ecosystem impacts resulting from the introduction of the
chironomid midge Eretmoptera murphyi to Signy Island in maritime Antarctica. The key finding was that
E. murphyi is the likely driver of an increase in inorganic nitrogen availability within the nutrient-poor soils in
which it occurs. When compared with the levels of inorganic nitrogen present in soils influenced by native
vertebrate wildlife aggregations, the increase in local nitrate availability associated with E. murphyi was similar
to that caused by deposits from seals and giant petrel colonies. Overall, available nitrate has increased by threeto five-fold in soils colonised by the midge, relative to undisturbed soils. This may ultimately impact rates of
decomposition as well as the native plant and micro-arthropod communities of Signy Island.
Antarctica
Invasion impacts
Chironomidae
Signy Island
Soil nitrogen
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