New Zealand Journal of Botany abstracts
Vegetation and peat characteristics of restiad bogs on Chatham Island (Rekohu), New Zealand
Beverley R. Clarkson
Louis A. Schipper
Landcare Research
Private Bag 3127
Hamilton, New Zealand
Email: bev@landcareresearch.co.nz
Bruce D. Clarkson
Centre for Biodiversity and Ecology Research
Department of Biological Sciences
The University of Waikato
Private Bag 3105
Hamilton, New Zealand
Abstract 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.
Keywords peat; bog; nutrients; disturbance gradient; Restionaceae; Waikato; Sporadanthus traversii; S. ferrugineus; Empodisma minus
B03019; Received 18 June 2003; accepted 1 October 2003; Online publication date 3 June 2004
New Zealand Journal of Botany, 2004, Vol. 42: 293-312
0028-825X/04/4202-0293 © The Royal Society of New Zealand 2004
PDF file of entire paper: Print-quality (6362K) | screen-quality (611K)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
