The altitudinal sequence of climax vegetation on mt anglem, stewart island

Abstract

The altitudinal gradient in vegetation on the north-eastern slope of Stewart Island's highest peak is described quantitatively. Eight sites were sampled between sea level and the summit (976 m) and four distinct communities have been recognised: (1) Lowland podocarp-broadleaved forest extending from sea level to about 300 m; (2) Montane Leptospermum-Dacrydium tall shrubland between about 300 m and 400 m; (3) Subalpine Olearia colensoi scrub extending from about 400 m to 950 m; above about 650 m, however, the scrub becomes increasingly restricted to steeper sites, being replaced on more gentle slopes by (4) Alpine herb moor, which also occupies the small summit plateau. Values are given for canopy height, basal area, and density of trees and small-trees, and density of shrubs, sub-shrubs, and herbs. Dominance and frequency values are presented for a stand of herb moor. The extent to which the altitudinal pattern is characteristic of Stewart Island as a whole is considered. The pattern is also compared with that in adjacent parts of the South Island. Differences are attributed mainly to the absence of silver beech, Nothofagus menziesii, from Stewart Island. Colobanthus affinis is recorded for the first lime.