Composition and function of the alien flora of New Zealand

Study summarizes the current knowledge of traits and distribution of naturalized plants in the Pacific archipelago

GBIF-mediated data resources used : 184,378 species occurrences
Aeonium arboreum
Aeonium arboreum (L.) Webb & Berthel. observed in Wellington, New Zealand by weedy1 (CC BY-NC 4.0)

Ranked among the world's top 25 biodiversity hotspots, New Zealand is an isolated archipelago in the South Pacific with very high endemism, including more than 80 per cent of reptiles and flowering plants.

The islands, however, have also been "ravaged by biological invasions" (Simberloff 2008), and today, more than half of the land area consists of ecosystems dominated by non-native plants.

To support a contemporary management strategy of naturalized plants, this study summarizes the current knowledge of traits and distribution of the alien flora of New Zealand.

By mapping GBIF-mediated occurrences of 1,798 naturalized species, the authors showed that alien plants are distributed mainly in larger, more northerly and more populated regions, with Auckland and Canterbury having the highest numbers.

Overall, these plants, currently comprising 43.9 per cent of the vascular flora, add 67 families and 649 genera to the total vascular flora. The naturalized group is more taxonomically diverse than the native population and has a much higher proportion of herbaceous and annual species—but a lower proportion of perennials.

Combined, such knowledge of taxonomic and functional differences between native and alien may guide the management of naturalized species from local to national scale.

Brandt AJ, Bellingham PJ, Duncan RP, Etherington TR, Fridley JD, Howell CJ, Hulme PE, Jo I, McGlone MS, Richardson SJ, Sullivan JJ, Williams PA and Peltzer DA (2020) Naturalised plants transform the composition and function of the New Zealand flora. Biological Invasions. Springer Science and Business Media LLC 23(2): 351–366. Available at: