Pattern and process of vegetation change (succession) in recent volcanic landscapes of New Zealand and Hawaii

Volcanic activity (including lava flows, debris flows and tephra eruptions) is a regular feature of many landscapes of the North Island of New Zealand and the Hawaiian archipelago. Over the last 35 years, we have been using a combination of the chronosequence and direct monitoring methodologies (Clarkson 1998; Walker et al. 2010) to research the pattern and process of vegetation change (succession) in these landscapes. The following account summarizes pattern and process from our main study sites: Whakaari (White Island), Rangitoto Island, Mt Tarawera, Mt Ngauruhoe, Mt Ruapehu, and Mt Taranaki in New Zealand and Mauna Loa in Hawaii. The main focus of this account is forest development following significant eruptions

Evaluation of the Hamilton City Council plants for Gullies programme

This evaluation found that the Hamilton City Council Plants for Gullies programme is successfully facilitating the restoration and enhancement of Hamilton City gullies by private gully owners. The mean number of native species in surveyed gullies was 2.1 in non-restored sites and 18.4 in restored sites. While the mean number of invasive species was 4.1 in non-restored sites to 2.6 in restored sites. This quantitative measure is a valuable indication of the ecosystem gains for Hamilton City. Hamilton gully owners are very satisfied with the Plants for Gullies programme; the mean satisfaction rating was 8.9 out of 10. These residents dedicate significant time and energy to restoring their gully sections; the mean time contribution of survey participants was 10.3 hours per month. Gully owners were found to be utilising knowledge acquired through participation in the programme to add valuable diversity to their gully ecosystems. This was repeatedly demonstrated by programme participants not only reintroducing the native plants supplied by the programme but also adding large quantities of privately-sourced plants. This investigation found that the Plants for Gullies and Gully Restoration programmes are effective in communicating key ecological restoration concepts. This was reflected by gully owner prioritisation of eco-sourcing, biodiversity and weed control as considerations in their restoration projects. The Gully Restoration Guide was found to be the most valuable component of the programme’s educational tools. However, it is recommended that this resource is updated to support the many gully owners who require information for advanced stages of ecological restoration. In summary, the Plants for Gullies programme is successfully delivering gully restoration assistance and advice to gully owners, which is resulting in significant improvements to Hamilton City’s gully systems. The programme is valued by all who are involved and could be recommended to other New Zealand cities as an effective model for environmental restoration and community engagement

Vegetation and peat characteristics of restiad bogs on Chatham Island (Rekohu), New Zealand

Restiad bogs dominated by Sporadanthus traversii on Chatham Island, New Zealand, were sampled to correlate vegetation patterns and peat properties, and to compare with restiad systems dominated by Sporadanthus ferrugineus and Empodisma minus in the Waikato region, North Island, New Zealand. Classification and ordination resulted in five groups that reflected a disturbance gradient. The largest S. traversii group, which comprised plots from central, relatively intact bogs, had the lowest levels of total nitrogen (mean 1.20 mg cm-3), total phosphorus (mean 0.057 mg cm-3), total potassium (mean 0.083 mg cm-3), and available phosphorus (mean 18.6 μg cm-3). Modification by drainage, stock, and fires resulted in a decline of S. traversii and an increase of Gleichenia dicarpa fern cover, together with elevated peat nutrient levels and higher bulk density. Compared with peat dominated by Sporadanthus ferrugineus or Empodisma minus in relatively unmodified Waikato restiad bogs, Chatham Island peat under S. traversii has significantly higher total potassium, total nitrogen, available phosphorus, bulk density, and von Post decomposition indices, and significantly lower pH. Sporadanthus traversii and Empodisma minus have similar ecological roles in restiad bog development, occupying a relatively wide nutrient range, and regenerating readily from seed after fire. Despite differences in root morphology, S. traversii and E. minus are the major peat formers in raised restiad bogs on Chatham Island and in Waikato, respectively, and could be regarded as ecological equivalents

Indigenous vegetation types of Hamilton Ecological District

The following descriptions of indigenous vegetation types and lists of the most characteristic species have been compiled for the major landform units of the Hamilton Ecological District, which lies within the Waikato Ecological Region (McEwen 1987). The boundaries of the Hamilton Ecological District correspond approximately to those of the Hamilton basin, with the addition of parts of hills and foothills at the margins of the basin. The vegetation descriptions and species lists are based on knowledge of the flora of vegetation remnants in the ecological district, historical records (e.g., Gudex 1954), and extrapolation of data from other North Island sites with similar environmental profiles