Fire management and biodiversity in Northern Australia

Perry, Justin James (2016) Fire management and biodiversity in Northern Australia. PhD thesis, James Cook University.

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Abstract

Fire is a significant ecological determinant of patterns of plant and animal distributions across the globe. This is especially so for the tropical savanna biome as fire is intrinsically linked with a dynamic weather-driven interplay between C4 grasses and other vegetation types. We know that climate change will dramatically alter global ecosystems in the future, but the implications for savanna ecosystems are less clear. The potential changes are often discussed in terms of how things may alter up to 100 years into the future. In most cases these forecasts are too abstract to translate for land managers who need practical advice that will allow them to adapt in real time and that acknowledges the considerable challenges they face now.

For this thesis I have sampled fire and vertebrate fauna in the dominant vegetation type in northern Australia, open savanna woodland, and used these data to test several hypotheses that will help decision makers and land managers better understand fire management both now and into the future. To adapt to future change and to make better decisions about the current conditions we need to understand the determinants of fire, how these are linked to climate, the impact of human intervention through various fire management strategies, and what the likely implications for biodiversity are.

In this thesis I examine fire and biodiversity at a variety of scales, ranging from pyro-diversity models derived for all of northern Australia to a set of representative sites surveyed on Cape York Peninsula for the three dominant vertebrate taxa (birds, mammals and reptiles). The thesis includes six chapters that begin at the broadest scale (all of northern Australia) and then drill down in scale for the various vertebrate fauna responses.

Chapter 1 introduces fire as a disturbance regime and a ubiquitous part of northern Australia land management. It outlines the structure of the thesis and describes the connectivity of chapters.

Chapter 2 sets the scene for the distribution of fire in northern Australia from a climatic perspective and explicitly links weather and vegetation to fire distribution in recent history. This places the contemporary distribution of fire in a broader temporal perspective and outlines the implications of fire on carbon emissions and describes the variance in annual and inter-annual fire distributions.

Chapter 3 compares contemporary fire management strategies with traditional Aboriginal burning and discusses the challenges of supporting traditional burning with modern requirements such as infrastructure protection and financial incentives for reducing greenhouse gas emissions.

In chapter 4 I explore the links between burning for greenhouse gas abatement and vertebrate fauna in savanna ecosystems of Cape York Peninsula. Carbon farming initiatives have rapidly developed in recent years creating incentives for broad scale changes to land management regimes. In the open carbon market a premium can be secured if additional benefits, such as biodiversity conservation or social advancement, can be quantified. In Australia, there is an accepted method for carbon abatement that requires shifting fire frequency from predominantly late to early dry season fires. There is an assumption and some evidence that this might accrue co-benefits for biodiversity. We tested this assumption by comparing terrestrial vertebrate biodiversity patterns (richness and abundance of reptiles, birds and mammals) against increasing fire frequency in the early dry season at the same spatial resolution as the savanna burning methodology.

Chapter 5 examines the contemporary distribution of mammals on Cape York Peninsula (data collected for this thesis) in comparison with limited historical data and changes in mammal fauna across northern Australia. I contextualise the changes in mammal populations with the historical disturbances present in the study area which includes changes to fire regimes.

Chapter 6 focusses on reptiles, one of the most abundant and diverse taxa in savanna ecosystems. Theoretically, if fire changes vegetation patterns then reptiles, as a heliothermic organism should be a good indicator of the impact of altered fire regimes.

Chapter 7 looks at changes in bird distributions across time in the study area. A systematic survey of the avifauna of Cape York Peninsula was conducted in the late 1990s and early 2000s providing an ideal basal dataset for measuring change in the avifauna. A subset (n > 600) of these sites, primarily within savanna landscapes, was selected for re-survey in 2008 to investigate changes in bird communities on Cape York Peninsula. Long-term monitoring can describe important patterns of species change over time, though in the case of large, highly seasonal environments like the tropical savannas, signals of change may manifest over decades rather than annually.

Chapter 8 discusses the broad implications of this research and describes how each chapter has collectively increased the understanding of the impact of fire on biodiversity in northern Australia.

This thesis provides the first major assessment of fire and biodiversity in the savanna ecosystems of Cape York Peninsula and uses novel analytical methods to demonstrate significant shifts in fire frequency in recent history. This dataset and the associated analysis and interpretation has provided a substantial improvement to the collective knowledge of fire and terrestrial vertebrate fauna across northern Australia.

Item ID: 48796
Item Type: Thesis (PhD)
Keywords: biodiversity, birds, Cape York Peninsula, climate change, conservation, effect of fire, fire frequency, fire management, fire, forest biodiversity, greenhouse gases, land burning, mammals, MAXENT, niche modelling, northern Australia, reptiles, savanna ecosystems, savanna woodland, species richness, temporal variation, vertebrate fauna, wildfire
Additional Information:

Publications arising from this thesis are available from the Related URLs field. The publications are:

Chapter 7: Perry, J.J., Kutt, A.S., Garnett, S.T., Crowley, G.M., Vanderduys, E.P., and Perkins, G.C. (2010) Changes in the avifauna of Cape York Peninsula over a period of 9 years: the relative effects of fire, vegetation type and climate. Emu, 111 (2). pp. 120-131.

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Date Deposited: 27 Apr 2017 04:59
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050101 Ecological Impacts of Climate Change @ 84%
16 STUDIES IN HUMAN SOCIETY > 1604 Human Geography > 160499 Human Geography not elsewhere classified @ 16%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960307 Effects of Climate Change and Variability on Australia (excl. Social Impacts) @ 16%
96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960805 Flora, Fauna and Biodiversity at Regional or Larger Scales @ 68%
95 CULTURAL UNDERSTANDING > 9599 Other Cultural Understanding > 959999 Cultural Understanding not elsewhere classified @ 16%
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