A Review of Vegetation Development Following Recent (Less-Than 450 Years) Volcanic Disturbance in North Island, New Zealand

Volcanic activity has damaged or destroyed at least 20,000 has of indigenous vegetation in the North Island in the last 450 years. The primary and secondary successions initiated are discussed and considered in relation to some recently proposed models of succession. Most of the variation relates to the scale and intensity of disturbance, and the type and heterogeneity of the substrate emplaced. Where disturbance has been extensive and severe, elements of slow 'classical' successions, from lichens and mosses to flowering plants, and facilitation by nitrogen-fixers such as Coriaria spp., are evident. In contrast, minor disturbance results in vegetative regrowth or regeneration of surviving species. Heterogeneity of substrate enables many taxonomic plant groups to establish more or less concurrently. Partial disturbance successions are not easily categorised and may contain elements of several successional models. The resource-ratio hypothesis of succession can be used to explain the general pattern of the volcanic successions outlined. Insufficient information, of the type suggested necessary by recent authors, is available to make detailed accurate predictions in respect of future volcanically-initiated successions. Recent volcanism has had a major influence on species distribution and vegetation patterns in the North Island.