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Plant traits and their effect on fire and decomposition

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thesis
posted on 28.03.2022, 02:23 authored by Saskia Grootemaat
Wildfires are a major disturbance worldwide with large effects on ecosystem functioning, species composition and nutrient cycling. A fundamental factor in wildfires is the fuel, namely, live and dead plant material. Plant species differ in their flammability, but the role of plant traits in this remains largely unknown. The decomposition rates of different plant materials (and species) can strongly affect the availability of fuel for potential wildfires.While the influence of leaf traits on litter decomposability is reasonably well studied, it has never been compared to the drivers of litter flammability. In this thesis I focused on these two important turnover processes of plant material, i.e., fire and decomposition. By comparing a wide range of species from south-eastern Australia, I investigated theexistence of general relationships between plant traits, flammability and litter decomposability. In experiments on individual leaves (Chapter 2) I found that morphological leaf traits (such as specific leaf area or dry mass) were most strongly correlated with interspecific variation in flammability, while decomposability was mainly driven by chemical traits. Similar results were found for bark, another important litter component of the Australian forests (Chapter 4). Bark ignitibility of smooth bark species was driven by bark mass per area, while decomposition was strongly associated with initial lignin concentration. Consequently, fire and decomposition, as two alternative fates for leaves or bark, were unrelated. Next, I demonstrated that leaf traits which affect the flammability of individual leaves (e.g. specific leaf area) continue to affect flammability when scaling up to fuel beds (Chapter 3). Can we use these findings on interspecific variation in leaf trait – flammability relationships to improve predictions of fire behaviour? In Chapter 5 I showed that the inclusion of leaf traits (especially leaf thickness) improved the prediction of individual leaf ignitibility. Altogether, this suite of studies increased our understanding of trait-effects on leaf and bark flammability and decomposability. Including plant traits in future analyses could improve the estimation of fuel loads and the prediction of wildfires.

History

Table of Contents

1. General introduction -- Burn or rot : leaf traits explain why flammability and decomposability are decoupled across species -- 3. Towards a better understanding of fuel bed flammability scaling up from individual leaves -- 4. Bark fates explored : decomposition and flammability of 10 woody species from the Sydney region (south-eastern Australia) -- 5. Models for leaf ignitibility based on leaf traits -- 6. General discussion.

Notes

Includes bibliographical references Thesis by publication.

Awarding Institution

Macquarie University

Degree Type

Thesis PhD

Degree

PhD, Macquarie University, Faculty of Science and Engineering, Department of Biological Sciences

Department, Centre or School

Department of Biological Sciences

Year of Award

2016

Principal Supervisor

Ian James Wright

Additional Supervisor 1

Peter M. Van Bodegom

Additional Supervisor 2

Hans (Johannes Hans C.) Cornelissen

Rights

Copyright Saskia Grootemaat 2015. Copyright disclaimer: http://mq.edu.au/library/copyright Copyright disclaimer: http://www.copyright.mq.edu.au

Language

English

Jurisdiction

New South Wales

Extent

1 online resource (197 pages) illustrations (some colour)

Former Identifiers

mq:49698 http://hdl.handle.net/1959.14/1108457