Evolution of the New Zealand mountain flora: Origins, diversification and dispersal

The New Zealand mountains provide a unique system in which to study the evolution of alpine plants. The relationship between the recent uplift of mountain habitats (5-2 million year ago (mya)) and floristic diversity has polarized hypotheses on the evolution of the alpine flora; suggestions have ranged from an ancient history in New Zealand to recent arrival by long distance dispersal from the Northern Hemisphere. Molecular phylogenies are now available for numerous New Zealand alpine plant groups and these provide insights into the evolution of this unique flora. Taken together with the fossil record, these studies suggest that many alpine lineages first arrived in New Zealand during the late Tertiary and subsequent radiations accompanied environmental upheaval in the Pliocene and Pleistocene. Ongoing studies are investigating the processes that contribute to morphological and ecological diversity in the New Zealand alpine flora.