Post-fire vegetation recovery in northern New Zealand: potential contributions of soil seedbanks, effects of heat-shock, and soil conditions

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dc.contributor.advisor Perry, G en
dc.contributor.advisor Schwendenmann, L en Wong, Alicia en 2017-11-20T03:42:43Z en 2017 en
dc.identifier.uri en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract The rarity of fire in New Zealand prior to human arrival meant much of the native flora lacks fire-adaptive traits. As a result, increased fire frequency associated with human settlement has driven widespread forest loss in New Zealand. Remnant forests are continuously threatened by recurrent fires and the invasion of exotic fire-adapted plants. Little, however, is known of either the effects of post-fire soil conditions on influencing post-fire community dynamics, or the potential contributions of soil seedbanks to the early stages of post-fire succession. This study seeks to evaluate the (1) effects of heat-shock (a fire-related germination trigger) on the germination on New Zealand soil seedbank, (2) the contribution (in terms of composition) of soil seedbanks to post-fire vegetation regeneration, and (3) to assess post-fire soils. Vegetation data and soil seedbank samples were collected across four study sites in northern New Zealand, and subsequent heat-shock experiments, shadehouse germination trials, soil bulk density, soil moisture, pH, and total carbon (C) and nitrogen (N) analyses were conducted. Compositional data from the germination trials and field vegetation surveys were analysed using classification and ordination. Comparisons showed a decoupling between the composition of the soil seedbank and post-fire regenerating vegetation. Soil seedbanks were dominated by herbaceous taxa, while the regenerating vegetation comprised predominately of native early-successor species such as Leptospermum scoparium and invasive, exotic fireadapted species such as Hakea sericea and Pinus radiata. Heat-shock experiments show that fire suppressed the overall germination of New Zealand species in the soil seedbank, while promoting the germination of species with persistent and fire-tolerant seeds (e.g. Paraserianthes lophantha and Ulex europaeus). Post-fire soils across the four sites were characterised by high bulk density, low moisture, and low total C and N concentrations. This study identified persistent and heat-tolerant seeds and post-fire soil conditions as contributors to positive fire-vegetation feedbacks in post-fire communities, which would likely increase their flammability and sensitivity to recurrent fires, and slow return-to-forest succession. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99264955013902091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights.uri en
dc.rights.uri en
dc.title Post-fire vegetation recovery in northern New Zealand: potential contributions of soil seedbanks, effects of heat-shock, and soil conditions en
dc.type Thesis en Environmental Science en The University of Auckland en Masters en
dc.rights.holder Copyright: The author en
pubs.elements-id 716282 en
pubs.record-created-at-source-date 2017-11-20 en

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