Succession in subalpine vegetation at Arthur's Pass, New Zealand
- Botany Division, D.S.I.R., Christchurch
In 1898 Cockayne described succession in subalpine vegetation which had been burnt eight years previously at Arthurs Pass. In 1932 Cockayne and Calder repeated the observations and Calder established ten charted transects, which were re-charted during the summer of 1965-66.
In subalpine scrub, the path of the succession is broadly as follows, although details vary from site to site:
1 year after the fire: appearance of Marchamia and ruderal angiosperms.
2-10 years: Hebe spp. and Cassinia fulvida enter and rise to dominance. Seedlings of climax species also enter, but are relatively slow-growing. Fire-tolerant herbs such as Hypolepis millefolum and Phormillm colensoi may be conspicuous.
40 years: Senecio bennettii becomes dominant, Hebe almost disappears.
75 years: Dracophyllum longifolium and later Phyllocladus alpinus regain their original dominance.
Low subalpine forest passes through comparable initial stages, but it is probably about 200 years before the characteristic small trees Dracophyllum traversii. Dacrydium biforme and Libocedrus bidwillii reach maturity, although their seedlings may appear within 40 years of a fire. In contrast, regeneration of destroyed Nothofagus solandri var. cliffortioides forest may be rapid, but there is very little tendency for beech to invade scrub and grassland beyond the the original forest boundaries. In Chionochloa grassland the effect of fire is to allow herb-field species—notably species of Celmisia—to achieve at least physiognomic dominance for a few years.