A COMPARATIVE STUDY OF BIRD ABUNDANCE AND DIVERSITY IN MATURE SECONDARY AND LOGGED MID-ALTITUDE RAINFORESTS IN NAKOBALEVU AND SAVURA, SOUTHERN VITI LEVU HIGHLANDS, FIJI ISLANDS. by Nitassha Kavita Shankaran A thesis submitted in fulfillment of the requirements for the degree of Master of Science in Biology © Nitassha Kavita Shankaran 2010 School of Biological and Chemical Sciences Faculty of Science, Technology and Environment The University of the South Pacific June, 2010 DECLARATION Statement by Author I, Nitassha Shankaran declare that this thesis is my own work and that, to the best of my knowledge, it contains no material previously published, or substantially overlapping with material submitted for the award of any degree at any institution, except where due acknowledgment is made in the text. ii ACKNOWLEDGEMENTS I would like to thank the following people in particular for their efforts in helping make this study a success: 5 The Darwin Initiative, BirdLife International Pacific and the University of the South Pacific who provided funding to complete this study 5 Dr. Timothy Markwell, Dr. Linton Winder, Dr. Uma Khurma, James Millett and Dr. Clare Morrison for their technical support and help with the logistics of the study 5 Vilikesa Masibalavu for introducing birding to me as an exciting activity and for teaching me a significant amount about bird identification 5 Avinesh Prasad and Dinesh Kumar for driving us to the study locations every morning 5 Staff of BirdLife International Pacific for assistance during training and research site establishment 5 Vido and Neno for keeping us safe in the forest 5 Janesh Kumar and Preetika Prasad for their support, proof-reading assistance and being my confidants in the tussles faced during this study 5 And to all other people who I have missed who deserve my due respect and gratitude I dedicate this thesis to my mother, Late Mrs. Sangita Sharma, who taught me the value of education, my brother, Anvil Shankaran, for his love and support and especially to my husband, Janesh Janendra Kumar, for his support and inspiration in whatever I do. iii ABSTRACT To establish the impact of logging on the diversity and abundance of forest birds in the mid-altitudinal rainforests of the Southern Viti Levu Highlands of Fiji, random point counts were carried out in mature secondary as well as recently logged forests. An overall total of 120 point counts were carried out from August to November, 2007 and January to February, 2008. This study showed that there were more individuals in recently logged forests at the two locations, Nakobalevu and Savura (ANOVA: F4, 116 = 31.66, P treatment = 0.000). In addition to this, there were significantly more bird species found in recently logged forests as well (ANOVA: F4, 116 = 19.61, P treatment = 0.000). These results were also reflected with results from the Shannon - Weiner Index where the species richness (S) was higher in recently logged forests compared to the mature secondary forests. The species richness was S=27 and S=24 in recently logged forests at Nakobalevu and Savura respectively. The evenness measure was higher in mature secondary forests than in recently logged forests indicating that in recently logged forests a few species have larger numbers but most species have low numbers. This study also established indicator species for the two forest types. Even though there were bird species with high associations with the mature secondary forest, they were extensively present in recently logged forests as well. Therefore, no indicator species were found specifically for the mature secondary forests. Barking pigeons (Ducula latrans), the Fiji bush-warbler (Cettia ruficapilla) and the Fiji white-eye (Zosterops exploratory) were found in higher numbers and had stronger associations with the recently logged forests at both Nakobalevu and Savura. The Fiji parrotfinch (Erythrura pealii) and the White-rumped swiftlets (Aerodramus spodiopygius) were the only two bird species which were only present in the recently logged forests. Other species that have been recorded in this study have shown to have flexible habitats, that is, they were found in both mature secondary and recently logged forests at both the study locations. This study indicates that logging does affect the bird abundance and diversity. Increases in species richness found at recently logged forests do not directly relate to iv conservation priorities as the additional species observed were associated with disturbed habitats and were of lower conservation concern than species that were associated with mature secondary forests. Results from this study show that even though species richness is higher in recently logged forests compared to mature secondary forests, the mature secondary forests have a more stable resident native breeding land bird population and therefore bird populations with a higher conservation priority. This study shows that Fijian forests and Fijian birds have some adaptability towards habitat disturbance. The avian ecosystem is able to recover after logging provided the forest is permitted to recover and where source populations survive. v CONTENTS Declaration ii Acknowledgements iii Abstract iv List of figures ix List of tables x CHAPTERS Chapter 1 1 Introduction 1 1.1 General study of Fiji 1 1.1.1 Location and topography of Fiji Islands 1 1.1.2 Climate 2 1.2 Fiji’s flora 3 1.3 Biodiversity conservation in Fiji 4 1.3.1 Biodiversity and conservation of wildlife in Fiji 4 1.3.2 Origin and distribution of birds in Fiji 6 1.3.3 Understanding of bird biodiversity 7 1.4 Loss of biodiversity caused by logging 7 1.4.1 Logging and its effects on bird populations 7 1.4.1.1 Treefall gaps 9 1.4.1.2 Fragmentation and habitat loss 10 1.4.1.3 Edge effects on bird population 12 1.4.1.4 Effects of logging on bird nesting 13 1.4.1.5 Invasive alien plants and animals 14 1.4.1.6 Unfavourable succession pathways: A 15 consequence of logging 1.5 The Study 17 1.5.1 Location, vegetation and habitat types 17 1.5.2 Logging disturbance history 20 1.6 Aims and objectives of the study 21 vi Chapter 2 22 Methodology 22 2.1 Sampling design and method 22 2.2 Statistical analysis 24 2.2.1 Two-way ANOVA 24 2.2.2 Shannon - Weiner index and Pielou’s species evenness 25 2.2.3 Dufrêne and Legendre’s Indicator Value Method (IVM) 25 Chapter 3 27 Results 27 3.1 Number of individuals 27 3.2 Number of species 28 3.3 Shannon - Weiner index and Pielou’s species evenness 31 3.4 Dufrêne and Legendre’s Indicator Value Method (IVM) 35 3.4.1 Nakobalevu 35 3.4.2 Savura 36 3.5.Diet type and habitat of bird species found in mature 39 secondary forest and recently logged forest Chapter 4 40 Discussion 40 4.1 Bird abundance in mature secondary forests and recently 40 logged forests 4.2 Species richness and diversity in mature secondary forests 41 and recently logged forests 4.3 Indicator species’ for mature secondary forests and 44 recently logged forests 4.4 Conclusion and recommendations 45 Bibliography 47 Appendix 1: Establishment of number of points required 62 vii Appendix 2:Diet, feeding habit and status of bird species recorded 64 at study locations viii LIST OF FIGURES Figure Description Page 1 Map of Fiji in the Eastern Melanesian island region 2 2 Location of Important Bird Areas in Fiji 6 3 Map of Important Bird Area FJ10 situated in the Southern 17 Highlands of Viti Levu, Fiji Islands 4 Map of study locations showing vegetation types from 19 forest survey conducted in 1992 5 Map of study plots at Nakobalevu and Savura 24 6 Mean number of individuals found in MSF and RLF at 28 Nakobalevu (n=30) 7 Mean number of individuals found in MSF and RLF at 28 Savura (n=30) 8 Mean number of bird species found in MSF and RLF at 30 Nakobalevu (n=30) 9 Mean number of bird species found in MSF and RLF at 31 Savura (n=30) ix LIST OF TABLES Table Description Page 1 Forest cover on larger islands within the Fiji group based 9 on National Forest Inventory 1990-1993 2 Fijian vernacular name and its scientific equivalent for 21 major tree species’ harvested from the recently logged forest in Nakobalevu and Savura Forest Reserve from 2000-2005 3 Sampling design used for the study 23 4 Results from two-way ANOVA for number of individuals 27 5 Total number of bird species found in the two forest types 29 at Nakobalevu and Savura 6 Results from two-way ANOVA for number of species 30 7 Relative abundance of bird species recorded in mature 32 secondary forest (MSF) and recently logged forest (RLF) at study locations 8 Bird species richness (S), absolute number of birds 35 observed (N) Shannon’s indices (H1) and Pielou’s species evenness (E) at each study location 9 Total number of individual birds and the total number of 35 families [ ] recorded at the study locations, Nakobalevu and Savura 10 Species established as being indicative of forest type at 37 Nakobalevu using the Indicator Value Method 11 Species established as being indicative of forest type at 38 Savura using the Indicator Value Method x CHAPTER 1 INTRODUCTION 1.1 General study of Fiji 1.1.1 Location and topography of Fiji Islands The Fiji Islands, located approximately 850 km east of Vanuatu, comprises of over 300 named islands. They are located at 16-20◦S latitude and 178◦E - 178◦W longitude (Fig 1). The cluster of more than 300 islands (97 of which are inhabited (Mueller- Dombois & Fosberg 1998) occupies an ocean territorial area of about 650,000km2, of which less then 3 percent (18333km2) is the total land area.