New Zealand Journal of Botany abstracts
Effect of Coriaria arborea on seed banks during primary succession
on Mt Tarawera, New Zealand
Beverley R. Clarkson
Landcare Research
Private Bag 3127
Hamilton, New Zealand
Lawrence R. Walker
Department of Biological Sciences
Box 454004
University of Nevada
Las Vegas, Nevada 89154-4004, USA
Bruce D. Clarkson
Warwick B. Silvester
Centre for Biodiversity and Ecology Research
Department of Biological Sciences
University of Waikato
Private Bag 3105
Hamilton, New Zealand
Abstract An experiment was conducted over two years
to investigate the effect of Coriaria arborea, a native nitrogen-fixing
shrub, on soil seed banks at sites representing a post-volcanic successional
sequence on Mt Tarawera, New Zealand. The sites ranged from bare volcanic
ash and lapilli substrate, through low-growing pre-Coriaria vegetation,
to dense stands of Coriaria scrub. Soils (to a depth of 50 mm) under
recently established Coriaria and older stands had more seedlings
(1096 and 1585 seedlings 0.4 m-2, respectively) and species (37
and 45 species 0.4 m-2, respectively) emerge than where there
was no Coriaria (243-320 seedlings 0.4 m-2, 14-25 species
0.4 m-2) and were the only soils with Coriaria seedlings.
In total, 3488 seedlings representing 63 taxa were recorded. Seeds were still
germinating after 24 months but rates declined markedly in the second year.
For example, Coriaria reached a germination peak at 8 weeks but continued
to germinate sporadically over the 2-year period. Tree species present in
young forest within 0.5 km of the sites were absent. Establishment of Coriaria
greatly accelerated an underlying trend of gradually increasing abundance
and diversity of seeds in the soil with vegetation age. Adventive, wind-dispersed,
and annual species were over-represented in the seed banks compared with
the regional evergreen forest-dominated flora. These proportions are expected
to decline as succession to forest gradually occurs.
Keywords Coriaria arborea; Mt Tarawera; nitrogen
fixation; seed bank; volcanic primary succession
B02005 Received 23 January 2002; accepted 6 August 2002; published 28
November 2002
New Zealand Journal of Botany, 2002, Vol. 40: 629-638
0028-825X/02/4004-0629 $7.00 © The Royal Society of New Zealand
2002
PDF file of entire paper: Print-quality (9704K)
| screen-quality (130K)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
