High altitude ecology: Progress in the study of South Island alpine vegetation
- Botany Department, University of Canterbury, Christchurch
Since 1962, when the present writer outlined a broad physiognomic classification of South Island alpine grasslands, there has been progress in the study of '[he main grasses and grasslands. This permits a reassessment of some features of the description and ecology of the vegetation. An event of first importance was the revision of taxonomy of the New Zealand Arundinoideae by Zotov (1963). Plants formerly included in the genus. Danthonia were placed by him in several other more natural genera. The larger snowgrasses (and some smaller species) fall into Chionochloa and most of the smaller species into Notodanthonia. Two other advances made by Zotov were his clarification of taxonomy within the genus Chionochloa and the outlining of distribution ranges of the various species.
The study of alpine vegetation in different parts of the South Island mountains by Wraight (1963) (Wairau Valley, Marlborough); Connor (1965) (Rakaia Valley, Canterbury); Mark (1962) (Central Otago); Mark and Burrell (1966) (Humboldt Mountains. West Otago) and Mark and Baylis (1963) (Western Fiordland) has helped to clarify the nature of plant communities dominated by native grasses.
In the following account there is brief mention of some points of taxonomy of species of Chionochloa which indicate that more study is needed in some groups. The ranges of some species are extended further than was shown by Zotov (1963). Vegetation zones above the timberline in the South Island are defined. Information additional to that given by Burrows (1962) is presented in short descriptions of conditions in the habitats of the more important alpine grasslands. Discussion is confined to the grassland vegetation dominated by species of the genus Chionochloa, above the actual or potential timberline. It should be understood that some of the species which dominate in alpine grasslands may also be common in subalpine, montane or lowland sites and some of the species more closely restricted to the alpine zone may occasionally descend to subalpine or montane sites.