Grazing and management of natural areas: reintroducing an indigenous factor?

The "moas and divaricating plants" hypothesis presented the first scientific challenge to the views that native vegetation had evolved in the absence of large herbivores. The present paper presents three situations where apparent ecological imbalance in natural vegetation may be related to the collapse of indigenous herbivores. First, it is noted that the "podocarp regeneration gap" is most evident on fertile soils supporting dense undergrowth, and that grazing may lead to vigorous podocarp regeneration. Secondly, attention is drawn to the floristic identity of Tasmanian "marsupial lawns" to New Zealand communities occupying areas with fluctuating water levels. Thirdly, it is pointed out that removal of grazing animals from grasslands, swamps and forest margins often leads to rampant growth of adventive grasses and weeds. It is therefore suggested that research and management should be flexible enough to consider that grazing may have positive roles in conservation.