Moa Browsing and Vegetation Formations, with Particular Reference to Deciduous and Poisonous Plants

Reconstruction of a generalised biology of moas suggests they would have been most abundant in grassland and scrubland, especially near forest margins and at lower altitudes. Their numbers would have been limited by the abundance of food and, on easier low altitude country, their feeding pressure would have been equivalent to that exerted by the introduced mammals. Steep and rough ground, dense sub-alpine scrub, and the risks to incubation and chick-rearing of summer snows, would have severely limited the extent to which moas could have used montane and alpine country.
As has been observed for divaricating shrubs, most deciduous and poisonous plants in New Zealand are low statured. They often dominate early in successions, forest canopy gaps, forest margins, open scrubland and grassland. Their general ecology is consistent with the hypothesis that browsing by moas was a significant selection force