Mt Tarawera: 2. Rates of Change in the Vegetation and Flora of the High Domes

The flora and vegetation of the four high domes of Mt Tarawera; Ruawahia, Tarawera, Wahanga and Plateau. are described, and successional rates and trends determined at some sites by comparing 1964 and present-day photographs and records. Although below the regional tree limit, the dome tops are dominated by scattered low shrubs, herbs, grasses, mosses and lichens. With increasing distance from the 1886 eruption craters vegetation com- plexity and rates of succession increase. Plateau dome vegetation is successionally the most advanced. In the last 18 years tutu (Coriaria arborea) has spread from adjoining valleys on to the dome crests and is now invading the remaining dome top vegetation. The flora of the high domes has increased since 1964 and a high proportion of the additional species are adventives. Adventive conifers are becoming increasingly abundant on the dome tops and may modify the natural succession which is to kamahi (Weinmannia racemosa)-broadleaf (Griselinia littoralis) forest.