King-Crab Invasion of the Antarctic Benthos

Skeleton-crushing (durophagous) predators have been excluded from benthic communities on the continental shelf off Antarctica for as long as tens of millions of years. Cold temperatures impose physiological limits that have prevented these predators from surviving. Climate change is now increasing ocean temperature at an unprecedented rate, relaxing the cold-thermal barrier and allowing some durophagous predators to return. Large, reproductively viable populations of lithodid king crabs have already been reported at slope-depths off the western Antarctic Peninsula, and it is theorized that their spatial distributions will increase with climate change. These predators have the potential to alter the Antarctic benthos drastically as they prey on vulnerable invertebrates. Here, we use Maximum Entropy (MaxEnt), a species distribution model (SDM) that utilizes presence-only occurrence data and environmental predictor variables to calculate probability of occurrence in unsampled areas. Our results provide evidence corroborating the hypothesis that lithodid populations will move upslope into shallower water with climate change. Our analysis is innovative in its application of SDM to address current gaps in our knowledge of lithodid populations in Antarctica. The model will aid in predicting optimal sampling strategies.