Cyclical Patterns of Regeneration in Subalpine Heathland Communities on the Bogong High-Plains, Victoria

Abstract

In the subalpine tract of the Bogong High Plains, cyclical patterns of regeneration occur within open heath and closed heath communities. In the Grevillea australis-Poa hiemata open grassy heath, most Grevillea shrubs are at present mature or senescent. Beneath the foliage of these shrubs, and in their canopy gaps, the dominant replacement species in the herb layer is snowgrass (Poa hiemata), and these shrubs tend to be replaced by snowgrass as they senesce. In the Phebalium squamulosum-Grevillea australis closed heath, both snowgrass and shrubs may occupy the senescent and gap phases of the dominant shrubs. Grazing by free-ranging cattle appears to favour the recolonisation of such gaps by shrubs rather than by Poa. In Prostanthera cuneata closed heath, regeneration in gaps was clearly shrub-dominated, with little establishment of snowgrass. Some shrubs, such as Grevillea, are obligate seed regenerators, whereas Phebalium and Prostanthera are capable of regeneration by both seed and vegetative means, such as root stock and layering stems. The life cycle of the major shrubs, from establishment to death, appears to require 30-50 years.