Eco-evolutionary priority and the assembly of the New Zealand flora

Eco-evolutionary priority effects, in which early arriving taxa pre-empt environmental niches and evolve to exclude or marginalise later arriving taxa, have been claimed to have influenced current vegetation communities in New Zealand. We here critically assess this claim. An examination of the entire New Zealand conifer and angiosperm flora shows that early arriving lineages do not have more species than later arriving lineages, and do not dominate regional species pools. A nationwide forest plot data set shows no influence of lineage age on tree dominance. Woody species with wide latitudinal ranges tend to be older, but plant height and biotically dispersed fruit exert a stronger influence. Range extent is not influenced by lineage age in the alpine zone. The New Zealand studies on which the original claim for eco-evolutionary priority effects is based are flawed as they sample only a small fraction of the flora and plant communities and base their conclusions on a few selected lineages. The large climatic and landscape alterations of the last 50 million years, changes in the type and number of immigrant taxa establishing, and extinction are likely to have been much more influential than arrival times in shaping the extant New Zealand flora.