The impacts of human activities are more apparent at present in the sub-Antarctic than in the Antarctic. The sub-Antarctic islands, despite their physical isolation in the Southern Ocean, are generally more accessible, have less challenging climates, and a longer history of human presence than the more southern latitudes of the Peninsula and continent (Frenot et al. 2005; Selkirk 2007; Convey and Lebouvier 2009; Trathan and Reid 2009). Parts of the sub-Antarctic and Antarctica (in particular, the Peninsula and Scotia arc, including the South Shetland Islands) have experienced the most rapid rates of climate change in the Southern Hemisphere over recent decades (Convey et al. 2009a; Turner et al. 2009), and are receiving the highest contemporary rates of human visitation, associated with the fisheries industry, military, tourism, and scientific activities (Frenot et al. 2005; Lynch et al. 2010).