AUSTRALIA’S BIODIVERSITY – RESPONSES TO FIRE Plants, birds and invertebrates A.M. Gill, J.C.Z. Woinarski, A. York Biodiversity Technical Paper, No. 1 Cover photograph credits Group of 3 small photos, front cover: • Cockatiel. The Cockatiel is one of a group of highly mobile birds which track resource-rich areas. These areas fluctuate across broad landscapes in response to local rainfall or fire events. Large flocks may congregate on recently-burnt areas. /Michael Seyfort © Nature Focus • Fern regeneration post-fire, Clyde Mountain, NSW, 1988. /A. Malcolm Gill • These bull ants (Myrmecia gulosa) are large ants which generally build small mounds and prefer open areas in which to forage for food. They are found on frequently burnt sites. Despite their fierce appearance, they feed mainly on plant products. /Alan York. Small photo, lower right, front cover: • Fuel reduction burning in dry forest. This burn is towards the “hotter” end of the desirable range. /Alan York Large photo on spine: • Forest fire, Kapalga, NT, 1990. /Malcolm Gill Small photo, back cover: • Cycad response after fire near Darwin, NT. /Malcolm Gill ISBN 0 642 21422 0 Published by the Department of the Environment and Heritage © Commonwealth of Australia, 1999 Information presented in this document may be copied for personal use or pub- lished for educational purposes, provided that any extracts are acknowledged. The views expressed in this paper are those of the authors and do not necessarily represent the views of the Department, or of the Commonwealth of Australia. Biodiversity Convention and Strategy Section Department of the Environment and Heritage GPO Box 636 CANBERRA ACT 2601 General enquiries, telephone 1800 803772 Design: Design One Solutions, Canberra Printing: Goanna Print, Canberra Printed in Australia on recycled Australian paper AUSTRALIA’S BIODIVERSITY – RESPONSES TO FIRE Plants, birds and invertebrates A. Malcolm Gill CSIRO Division of Plant Industry J.C.Z. Woinarski Parks and Wildlife Commission of the Northern Territory Alan York State Forests of New South Wales Biodiversity Technical Paper, No. 1 2 Introduction to Biodiversity Technical Paper No. 1 This is the first of the new Biodiversity Technical • Malcolm Gill, CSIRO, Canberra, who Series to be published by the Commonwealth addresses the effects of fire events on plant Department of the Environment and Heritage. biodiversity; The series has been initiated to collate and make • John Woinarski, Parks and Wildlife available information on the conservation and Commission, Northern Territory, who has sustainable use of Australia’s biodiversity to all prepared a review of the literature those involved or interested in biodiversity in concerning the impacts of fire on Australian Australian environments. birds and an annotated bibliography which The papers in this publication have been collates references to fire and Australian written by scientists with expertise in fire and its birds; and effect on Australia’s biodiversity. The papers will • Alan York, then of NSW State Forests, who add considerably to the continuing debate on fire assesses whether frequent hazard reduction in Australia. They will increase access to burning is a sustainable long-term information on how major elements of Australia’s management practice with regard to the biodiversity respond to fire and will be of conservation of terrestrial invertebrate significance to land management agencies, land biodiversity. Alan’s work was made possible by managers and policy makers at all levels. The papers have been prepared for the the foresight of NSW State Forest in initiating Biodiversity Conservation Branch of Environment a long-term project in which data was collected Australia, Department of the Environment and on the same sites for some 20 years. Heritage, Canberra by: The papers were originally prepared for Environment Australia in 1996. 3 4 CONTENTS Biodiversity and bushfires: an Australia-wide perspective on plant-species changes after a fire event 9 A. Malcolm Gill Centre for Plant Biodiversity Research, CSIRO Division of Plant Industry, ACT Summary 11 1. Preamble 13 2. Measurement of Biodiversity for Studies of ‘Disturbance’ Effects 15 2.1 What is Biodiversity? 15 2.2 Measures of biodiversity 15 2.3 Functional groups and measures of plant-species diversity 18 2.4 Declared species identities and diversity measures 20 2.5 Discussion 20 3. Models of Changes of Plant Diversity after Fire 23 3.1 Species richness (S-t models) 23 3.2 Species-area relationships (S-A models) 24 3.3 Rank-abundance and rank-cover relationships (i-mi and i-mc models) 25 3.4 Rank trajectories (i-t models) 25 4. Field Methods and Observed Changes in Plant Diversity after Fire 29 4.1 Before-and-after fire comparisons 29 4.2 Comparing adjacent burnt and unburnt stands 29 4.3 Chronological ordination using sites with different ages since fire 34 4.4 Plots, in which changes are observed in situ 35 4.5 Inferential methods 36 4.6 Discussion 37 5. Interpretation of data 39 5.1 Patterns of richness after fire: invasion-caused changes in composition 39 5.2 Patterns of richness after fire: simplification, no invasion 40 5.3 Distribution of patterns of richness change 41 5.4 A plant-community dynamics viewpoint 42 6. Fire Management of Plant Diversity 43 7. Research on Shifts in Plant Diversity after Fire 45 8. Conclusions 47 9. Acknowledgements 48 10. References cited 49 5 Fire and Australian birds: a review 55 J. C. Z. Woinarski Parks and Wildlife Commission of the Northern Territory Summary 57 1. Introduction 59 2. History of Fire Regimes 61 3. Fire Regimes and their Impacts on Birds: A Review Across Main Environments 63 3.1 Coastal Heaths and Thickets 63 3.2 Mallee 67 3.3 Temperate Eucalypt Open Forests 69 3.4 Temperate Woodlands 73 3.5 Tropical Eucalypt Open Forests and Savanna Woodlands 74 3.6 Tussock Grasslands 76 3.7 Hummock Grasslands 77 3.8 Acacia Shrublands and Woodlands 77 3.9 Other Habitats 78 3.10 Special Case: Islands 78 4. Research Adequacy Methods and Priorities 79 5. Conservation Overview 83 6. References 85 7. Tables 103 Table 1. Scientific Names of Birds mentioned in Text 103 Table 2. Summary Table of Incidence of Subects in Fire-Bird References 106 Table 3. Threatened Bird Taxa for which Inappropriate Fire Regime has been listed as a Threatening Process 108 Fire and Australian birds: an annotated bibliography 113 J. C. Z. Woinarski Parks and Wildlife Commission of the Northern Territory 1. Introduction 115 2. Acknowledgements 116 3. References 117 6 Long-term effects of repeated prescribed burning on forest invertebrates: managment implications for the conservation of biodiversity 181 Alan York Centre for Biodiversity and Bioresources, School of Biological Sciences, Macquarie University Acknowledgements 182 Executive Summary 183 1. Introduction 187 2. Methodology 189 2.1 Study Area 189 2.2 Experimental Design 189 2.3 Measurement of Environmental Parameters 192 2.3.1 Understorey Vegetation Structure 192 2.3.2 The Litter Environment 192 2.3.3 Sticks and Logs 192 2.3.4 Insolation 192 2.3.5 The Soil Environment 192 2.4 Terrestrial Invertebrate Communities 193 2.5 Analytical Procedures 193 2.5.1 Treatment, Exposure and Position Effects 193 2.5.2 Inter-relationships Between Environmental Variables 194 2.5.3 Terrestrial Invertebrate Communities 194 3. Results 199 3.1 Environmental Parameters 199 3.1.1 Understorey Vegetation Structure 199 3.1.2 Litter Biomass 202 3.1.3 Sticks & Logs 203 3.1.4 Insolation 204 3.1.5 The Soil Environment 204 3.2 Inter-relationships Between Environmental Variables 204 3.3 Terrestrial Invertebrate Communities 207 3.3.1 Ordinal Diversity 207 3.3.2 Invertebrate Abundance 207 3.3.3 Invertebrate Species Richness 213 3.3.4 Community Composition 217 3.3.5 Community Structure 234 3.3.6 Biodiversity Indicators 240 7 4. Discussion 243 4.1 Habitat Structure 243 4.2 Terrestrial Invertebrate Communities 245 4.2.1 Invertebrate Abundance 245 4.2.2 Invertebrate Species Richness 246 4.2.3 Community Composition 248 4.2.4 Community Structure 251 4.2.5 Biodiversity Indicators 253 5. Conclusions 257 References 261 BIODIVERSITY AND BUSHFIRES: An Australia-wide Perspective on Plant-species Changes after a Fire Event A. Malcolm Gill Centre for Plant Biodiversity Research, CSIRO Division of Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia Biodiveristy and bushfires SUMMARY Fires can have major effects on plant-species specified life stage (mature) through ‘functional diversity. These effects occur through variations groups’. Major ‘functional groups’ are ‘sprouters’, in fire regimes but are most obvious in the ‘seeders’, and ‘ephemerals’. Groups of species changes that take place after a fire event, the topic which can reproduce without fire are the ‘tolerant’ of this review. Attention here is biased toward or ‘requiring’ species. Using subdivisions of these vascular plant species, the source of most data. groups can assist our understanding even further. Trends observed in these data may differ from Models allow one to explore a wider range of those observed for non-vascular plants, vertebrate variability than is currently known. Thus, while animals or other life forms. species-area, rank-performance and species- How we measure ‘diversity’ is important to richness may all be expected to change with time the way we perceive the effects of fires. Variables after fire, the way they do so will be affected by that contribute to measures of diversity include the functional groups present and their the number of species present in an area, the area contributions to the total species composition. itself, and the numbers of individual plants per Data on the changes of species numbers and species. In some cases, plant cover, height or other variables with time since fire come from a biomass for each species may be more useful range of vegetation types in Australia.