Hello New Zealand

TL;DR: In terms of evolution on Pacific islands, Cowie and Holland as discussed by the authors set New Zealand apart, as many have done before, as being continental, the implication being that the evolution of New Zealand biota is somehow subject to different processes from those of oceanic islands.

Abstract: Cowie & Holland (2006) give a timely reminder of the biological importance of islands. The crux of their paper is the significance of oceanic islands in the study of biological evolution. Island biodiversity is not just an outcome of the lottery of arrival and extinction (MacArthur & Wilson, 1967), but of adaptive speciation. However, in terms of evolution on Pacific islands, Cowie & Holland (2006) set New Zealand apart, as many have done before, as being continental – the implication being that the evolution of New Zealand biota is somehow subject to different processes from those of oceanic islands. Is this justified? New Zealand has long been of interest to biogeographers and other biologists. Conservationists, phylogeneticists, ecologists, evolutionists and geneticists alike all draw attention to the distinctive nature of New Zealand plants and animals and it is widely held that this distinctiveness is the result of ancient isolation/origin. New Zealand’s position in the Southern Hemisphere, its relatively large size compared to other islands of the Pacific and its distinctive assemblage of biota characterized by many taxonomic absences, the presence of apparently archaic lineages and aberrant species have all attracted attention. However, the accepted idea that New Zealand is an ancient continental landmass distinguishes it from oceanic island systems that are foci for evolutionary study, and in particular for the study of the role of dispersal (Cowie & Holland, 2006). The archipelagos of Hawaii and the Galapagos are of volcanic origin, and their terrestrial surfaces are the product of hot-spot volcanism. These islands are the tops of substantial volcanoes built upon oceanic crust. The age of these islands can be estimated accurately using radiometric methods (e.g. Fleischer et al., 1998), and their biota can be definitively inferred as having originated via dispersal. The attraction oceanic island systems hold for evolutionists is that they represent natural experiments with definable histories and Allan Wilson Centre for Molecular Ecology and Evolution, IMBS, Massey University, Private Bag 11-222, Palmerston North, New Zealand, Bio-protection and Ecology Division, Lincoln University, PO Box 84, Lincoln, New Zealand and GNS Science, PO Box 30-368, Lower Hutt, New Zealand