Antarctica, the sub-Antarctic islands and surrounding Southern Ocean are regarded as one of the planet’s
last remaining wildernesses, ‘insulated from threat by [their] remoteness and protection under the Antarctic
Treaty System’. Antarctica encompasses some of the coldest, windiest and driest habitats on earth. Within
the Southern Ocean, sub-Antarctic islands are found between the Sub-Antarctic Front to the north and the
Polar Front to the south. Lying in a transition zone between warmer subtropical and cooler Antarctic waters,
these islands are important sentinels from which to study climate change. A growing body of evidence
now suggests that climatically driven changes in the latitudinal boundaries of these two fronts define the
islands’ short- and long-term atmospheric and oceanic circulation patterns. Consequently, sub-Antarctic
islands and their associated terrestrial and marine ecosystems offer ideal natural laboratories for studying
ecosystem response to change. For example, a recent study indicates that the shift in the geographical
position of the oceanic fronts has disrupted inshore marine ecosystems, with a possible impact on top
predators. Importantly, biotic responses are variable as indicated by different population trends of these top
predators. When studied collectively, these variations in species’ demographic patterns point to complex
spatial and temporal changes within the broader sub-Antarctic ecosystem, and invite further examination of
the interplay between extrinsic and intrinsic drivers.
