Institute of Advanced Studies School for Environmental Research Thesis for M.Sc. by Research _________________________________________________________________________________________________ Demography and Management of Top End Bamboo, Bambusa arnhemica . ________________________________________________________________ Nicholas John Hogarth Student no. 141703 30 - June - 2006 Supervisors Dr Donald C. Franklin Professor David Bowman Professor Barry Brook DECLARATION I hereby declare that, with the qualification stated below, the work herein submitted as a thesis for the degree of Master of Science at Charles Darwin University is an account of my own research and contains no work previously published or submitted for a degree at any tertiary institution. All references to ideas and work of other researchers have been specifically acknowledged. I assisted in the final year of fieldwork of a five-year program that was designed and managed by my supervisor, Dr Donald Franklin. However, I was responsible for all of the data entry, and the analyses and interpretation of the data as presented in this thesis. I was also responsible for the application of the results of this research in the draft Management Program for B. arnhemica as presented in Chapter 3 of this thesis. I was the primary author of the draft management program with assistance from Dr David Liddle from the Parks and Wildlife Service and my supervisor Dr Donald Franklin. ___23 ___/___3___/__2007 ___ Date - i ACKNOWLEDGEMENTS The Parks and Wildlife Service of the Northern Territory provided a vehicle for the fieldwork component of this study, and in-kind support for the development of the management program (many thanks to Dr David Liddle from Parks and Wildlife for his guidance and input to the management program). This thesis, with the development of the management program, represents the final stage of the bamboo research program instigated by Parks and Wildlife back in 1999. The School for Environmental Research (SER) at Charles Darwin University provided my scholarship and the operational funds to achieve the objectives of this study. For making this happen I am grateful to Professor David Bowman and Professor Bruce Campbell. I wish to whole-heartedly thank my excellent supervisor, Dr Donald Franklin, for his outstanding support, endless patience, and for having done such high-quality, groundbreaking work on the biology and ecology of Bambusa arnhemica . I would like to thank all the SER staff and students who were involved for their input and support; especially Louis Elliot, Jan Riley, Caroline Lehman and Aaron Petty (the ‘banana bread club’), and also Julian Gorman and Trisha Butler. I would also like to acknowledge Gina and Mike Ostwald from Mary River Park, for their permission to conduct the fieldwork on their property, their support and warm hospitality. However I reserve my final thanks for all my wonderful family and friends, especially Hannah Brodie-Hall, for their love, support and belief in me. - ii ABSTRACT In this study, I aim to provide fundamental demographic knowledge about the dynamics of culm recruitment and clump development for the Top End bamboo, Bambusa arnhemica in its natural habitat. A draft management program dealing with shoot harvest and other issues is developed, with the aim that the program be adopted under the Territory Parks and Wildlife Conservation Act 2005 . Some of the key results from the demographic study were: • Leafy culm basal area is the main driver of productivity. • Parents of new culms were mostly attributable to one and two year-old culms. • Productivity was not affected by the size of the clump; except at higher culm densities where congestion caused reduced productivity. • Small culms have higher rates of mortality than larger culms. • Most culms go through a state of senescence before dying, which can persist for many years. Fires, harvesting and herbivory were major extrinsic disturbances with significant effects on culm demographics. Common responses to these disturbances included small, congested clumps, reduced culm size, low productivity, and reduced culm longevity. Unexpected flowering was a significant intrinsic disturbance, and resulted in increased culm mortality and a dramatic decrease in the number, size and productivity of recruits in the year preceding flowering. The key message from these responses is that any action that reduces the vigour of the leaf canopy, or depletes the energy store in the rhizome, may affect the productivity, clump expansion and overall health of a bamboo clump. The management of bamboo habitat and the harvesting prescriptions outlined in the management program are designed to maintain the health and sustainability of B. arnhemica . Changes to the Territory Wildlife Regulations were recommended in regards to royalty payments for commercial harvest, bag-limits for non-commercial harvest, and seasonal limitations for commercial harvesting. - iii TABLE OF CONTENTS Chapter 1: General background 1 Introduction 2 The bamboos 3 Bamboo in Australia 7 The biology and ecology of Bambusa arnhemica 9 The history of Bambusa arnhemica 14 Management of wild bamboo 16 Aims and layout of thesis 17 Chapter 2: Demographic study 19 Introduction 20 The lifecycle of semelparous bamboos 21 Demography of wild, clumping bamboos 23 Objectives 28 Methods 29 Study region 29 Study sites 30 Sampling design 32 Culm data collection 33 Clump data collection 34 Data analysis 35 Results 36 What is the best way to measure clump size and recruitment? 36 How did clump biomass, productivity & culm size vary over time? 39 Culm survival, senescence and mortality 43 Clump size, density and productivity 48 Parentage 51 Discussion 55 Measures of productivity for wild bamboo 55 The biological processes underlying productivity 56 The impact of disturbances… 57 - iv Culm survival, senescence and mortality 60 Parentage 62 Conclusions 62 Chapter 3: Management program 64 Preamble 64 A Management Program for Top End Bamboo Bambusa arnhemica 65 TABLE OF CONTENTS 66 1 INTRODUCTION 68 1.1 Species subject to management 68 1.2 Supervisory authority 68 1.3 Legislation and international obligations 68 1.3.1 Northern Territory 68 1.3.2 Other States and Territories 69 1.3.3 Commonwealth 70 1.3.4 International 70 1.4 Status and management issues 70 1.4.1 Flowering and die off events 71 1.4.2 Fire 72 1.4.3 Impacts from harvesting and animals 73 1.4.4 Land clearing 73 2 AIMS AND OBJECTIVES 74 3 MANAGEMENT MEASURES 76 3.1 Land management 76 3.1.1 Non-riparian bamboo 76 3.1.2 Parks and reserves 76 3.1.3 Land clearing and bioregional planning 77 3.2 Non-commercial harvest 77 3.2.1 Traditional harvest 77 3.2.2 Non-traditional harvest for personal use 77 3.3 Commercial harvest 78 3.3.1 Permits, licenses and tenure 78 3.3.2 Harvest limit determination 79 3.3.3 Shoot harvest 79 - v 3.3.4 Culm harvest 80 3.3.5 Whole plant harvest 81 3.3.6 Seed 81 3.3.7 Fees and royalties 81 3.3.8 Harvesting returns 81 3.4 Research priorities 82 3.5 Public education and awareness 82 4 MONITORING AND ASSESSMENT 83 4.1 Impact monitoring 83 4.2 Assessment 83 4.3 Feedback mechanisms 83 5 REPORTS 83 6 COMPLIANCE 84 6.1 Enforcement 84 6.2 Penalties 84 7 REVIEW OF PROGRAM 84 8 INTERPRETATION 85 9 BACKGROUND INFORMATION 85 9.1 Historical and traditional use 85 9.2 Recent use 85 9.2.1 Cultivation 85 9.2.2 Harvesting 86 9.3 Biology & ecology 87 9.3.1 Description 87 9.3.2 Distribution, abundance and habitat 87 9.3.3 Life history and demography 89 9.4 Response to disturbance 90 9.4.1 Flowering 90 9.4.2 Fire 90 9.4.3 Harvesting and herbivory 91 10 GLOSSARY 92 11 REFERENCES 93 12 ACKNOWLEDGEMENTS 95 - vi Chapter 4: Synthesis & conclusions 96 Demography 96 Management of a wild bamboo 97 Recommended changes to the Territory Wildlife Regulations 98 Royalty payments 98 ‘Bag limit’ for non-commercial harvesting 99 Limitations to commercial shoot harvesting 99 References 101 - vii LIST OF FIGURES Chapter 1: General background Figure 1.1 : World distribution of native bamboo. 3 Figure 1.2 : The natural distribution of three native species of woody bamboo in Australia. 8 Figure 1.3 : Natural distribution of Bambusa arnhemica . 10 Figure 1.4 : Some morphological features of Bambusa arnhemica . 13 Chapter 2: Demographic study Figure 2.1 : The relationship between two plausible measures of clump size (clump area and leafy culm basal area) at a. the Mary River site and b. the Owens Lagoon site. 37 Figure 2.2 : The relationship between two measures of culm recruitment: number of recruits per clump and sum of recruit basal area per clump. 37 Figure 2.3 : Productivity of Bambusa arnhemica clumps using recruit basal area and leafy culm basal area for clump size at two sites. 39 Figure 2.4 : Trends over time at the Mary River and Owens Lagoon sites: (a) leafy culm basal area summed within sites, (b) recruit basal area summed within sites, (c) mean recruit density with clumps as replicates and (d) mean recruit diameter. 41 Figure 2.5 : Culm recruitment and size at two sites over time; Mary River site (a) and Owens Lagoon site (b). 42 Figure 2.6 : Annual culm-status transitions at the Mary River site (a & c), and the Owens Lagoon site (b & d). 43 Figure 2.7: Summary of annual culm status change for leafy culms (a & b), senescent culms (c & d) and dead culms (e & f) of unknown and known-age cohorts at two sites. 46 Figure 2.8 : Annual culm survival in relation to size (dbh cm) at the Mary River site (a) and the Owens Lagoon site (b). 47 - viii Figure 2.9 : The relationship between recruit size and clump size at the Mary River site (a.) and the Owens Lagoon site (b.) in 2001.