A study of montane tussock grassland with special reference to the growth, seeding and behaviour of the principal tussocks and grasses

Abstract

Tussock Grassland is the indigenous grassland of New Zealand. It occupies an area of some 14,000, 000 acres of which approximately 13,000,000 acres occur in the South Island. Originally tussock grassland occupied most of the land on the eastern side of the Southern Alps to the coast. Most of the Lowland Tussock Grassland has been cultivated and sown to pastures or to crops, but the Montane Tussock Grassland together with Sub-alpine and Alpine areas remain more or less in their original form modified by grazing and burning. The Montane Tussock Grassland occupies an area of some 6,000,000 acres or approximately one-seventh of the occupied land of New Zealand and extends from the average limit of the heavy western rainfall forest to the cultivated pastures of the foothills and plains. From Marlborough to Southland on the eastern side of the Southern Alps, Montane Tussock Grassland stretches in an almost unbroken belt, interrupted here and there by forest mainly of Southern Beech (Nothofagus). The Montane Tussock Grassland provides a natural pasturage for the flocks of the high-country runs. But in addition, most of these runs have available sub-alpine and alpine areas where sheep graze during the summer months. However, the carrying capacity is determined by the available, relatively snow-free country during the winter months in the Montane belt. This thesis is a study of the principal tussocks and grasses of Montane Tussock Grassland. Studies were conducted in the Waimakariri River Basin in the vicinity of Cass and Craigieburn where rainfall is moderate and rabbits are practically non-existent. Plants were pegged for regular measurements; enclosures were erected and plots were laid out to compare changes in the density of cover and botanical composition between grazed and ungrazed plots; measurements were made on the effect of burning on the principal tussocks. These studies were made between September and June, 1946-1947.