Summary
The ice-free habitats of continental Antarctica are among the most geographically isolated on Earth. Colonization of Antarctica requires the immigration of dissemules from distant biotic sites across large distances of snow or open ocean. Aerobiological sampling on the Antarctic Peninsula suggests that immigration is often highly stochastic, relying not on prevalent winds or ocean currents but instead on chance events such as tropical storms and polar blizzards. For this reason colonization is likely to be episodic, involving the deposition of an aerial suspension of plant propagules by storm events or the vagaries of the migratory behaviour of birds (e.g. Arctic tern, Sterna paradisaea). In this lecture I will explore how this stochastic input can affect the trajectory of Antarctic community development. I ask whether episodic immigration can explain why adjacent ice-free sites separated by short distances and similar in climatic and edaphic conditions often support radically different biotas? What light does Antarctica shed on the role of recruitment and colonization processes in temperate and tropical latitudes?