Gumede Silindile Thobeka 2020
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Taxonomic, functional, and avian community dynamics in selected Southern Mistbelt Forests of southern KwaZulu-Natal and the Eastern Cape, South Africa Silindile T. Gumede Submitted in fulfilment of the academic requirements for the degree of Doctorate of Philosophy in the discipline of Ecological Sciences School of Life Sciences College of Agriculture, Engineering and Science University of KwaZulu-Natal Pietermaritzburg Campus. 2020 ABSTRACT Human population increase and landscape transformation result in the reduction of natural habitats, such as forests, causing changes in forest patch composition, habitat amount, patch size, isolation, shape, and edges. This is challenging specialist such as Orange Ground-thrush (Geokichla gurneyi) and Lemon Dove (Aplopelia larvata) species unable to survive in fragmented habitats and also influencing the composition and distribution of avian species assemblages. Therefore, the main aims of this multifaceted study were to (1) assess the habitat requirements of two forest specialised bird species, the Orange Ground-thrush (Geokichla gurneyi) and the Lemon Dove (Aplopelia larvata); (2) identify if avian assemblage diversity and species functional trait diversity show consist patterning across different landscapes in a forest ecosystem; (3) determine the influence of vegetation structures on the taxonomic and functional diversity of avian forest species, and (4) modelling how to connect forest patches of higher functional diversity. In 2018-2019, we conducted a series of camera-trap surveys of 21- day periods and fixed-radius point-count surveys at 420 sites across 94 forest patches of Southern Mistbelt Forest of southern KwaZulu-Natal and Eastern Cape, South Africa, during the breeding and non-breeding seasons in conjunction with surveys of microhabitat structural covariates. Firstly, we modelled the probability of occupancy and detection for the selected two species, which showed that forest specialist species prefer a highly diverse habitat structure. Secondly, we quantified functional diversity measures based on species’ trait per patch to measure the influence of habitat and landscape configuration on each measure. This resulted in functional diversity measures which were highly influenced by patch size, the distance between patches and diverse landscape and habitat. Thirdly, we conducted RLQ analyses to examine the association between avian functional traits and microhabitat structures present at each forest patch. We found there was a significant difference in vegetation structure and species richness between forest patches. Lastly, we ranked the functional diversity ii measures scores of avian communities present at each forest patch to identify core habitat patches responsible for the contribution of high functional diversity measures. Protection of natural forest habitat and diverse landscapes is important in preserving avian communities. iii PREFACE The data described in this thesis were collected in the Southern Mistbelt Forest of KwaZulu- Natal and Eastern Cape Provinces, Republic of South Africa, from (May-August) and (October-February) of 2018 and 2019. Fieldwork was done while registered at the School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, under the supervision of Prof Colleen T. Downs, Dr David A. Ehlers Smith and Dr Yvette C. Ehlers Smith. This thesis, submitted for the degree of Doctorate of Philosophy in the College of Agriculture, Engineering, and Science, University of KwaZulu-Natal, Pietermaritzburg campus, represents original work by the author and has not otherwise been submitted in any form for any degree or diploma to any University. Where use has been made of the work of others, it is duly acknowledged in the text. …… ……. Silindile T. Gumede December 2020 I certify that the above statement is correct, and as the candidate’s supervisor, I have approved this thesis for submission. …………………………. Prof Colleen T. Downs (Supervisor) December 2020 iv COLLEGE OF AGRICULTURE, ENGINEERING, AND SCIENCE DECLARATION 2 – PUBLICATIONS DETAILS OF CONTRIBUTION TO PUBLICATIONS that form part and/or include research presented in this thesis. Manuscript 1 S Gumede, CT Downs, DA Ehlers Smith, YC Ehlers Smith, MS Maseko Occupancy of two forest specialist birds in the Southern Mistbelt Forests of KwaZulu-Natal and Eastern Cape, South Africa Author contributions: SG, DAE and YCE conceived paper with CTD. CTD sourced funding. SG, SPN and MS collected data. SG and analysed the data, and wrote the draft paper. CTD, DAE, MSM and YCE contributed valuable comments to the manuscript. Manuscript 2 S Gumede, CT Downs, DA Ehlers Smith, YC Ehlers Smith What are the landscape-scale drivers of avian species richness and functional diversity in KwaZulu-Natal and Eastern Cape Mistbelt Forests? Author contributions: SG, DAE and YCE conceived paper with CTD. CTD sourced funding. SG, SPN and MS collected data. SG analysed the data, and wrote the draft paper. CTD, DAE, and YCE contributed valuable comments to the manuscript. Manuscript 3 S Gumede, CT Downs, DA Ehlers Smith, YC Ehlers Smith The influence of the microhabitat structure on avian communities of Southern Mistbelt Forest Author contributions: SG, DAE and YCE conceived paper with CTD. CTD sourced funding. SG, SPN and MS collected data. SG analysed the data, and wrote the draft paper. CTD, DAE and YCE contributed valuable comments to the manuscript. vi ACKNOWLEDGEMENTS Firstly, I would like to thank God for achieving this dream of my life. I am so grateful to my supervisor, Prof Colleen Downs, for her assistance both academically and financially, and her patience with me since the beginning of my postgraduate studies. She took me under her wing, built my confidence and made me who I am today. I would also like to thank my co-supervisors, Dr David Ehlers Smith and Dr Yvette C Ehlers Smith, for their support and help throughout this project. The National Research Fund foundation (ZA) is thanked for providing research funding support. I am extremely grateful to Nasiphi Bitani, Nomaswazi Kubheka, Mfundo Maseko, Samkelisiwe Ngcobo, Lereko, Abidemi Raji and Mbali Sosibo for the good times we had during this journey of my life, and your prayers; I love you all. A special thanks to Bongumusa Jilajila for his moral support and patience throughout this project. To my mother, this one is for you; thank you for believing in me. A special thanks to my siblings for always making me feel special, all I want is to lead all of you rightfully. I am dedicating this thesis to my late grandmother, who raised me to be the woman I am today. “God promises to make something good out of the storms that bring devastation to your life” Romans 8:28 viii Silindile Thobeka Gumede about to go in to the field to conduct the forest research she loves. ix TABLE OF CONTENTS ABSTRACT .............................................................................................................................. ii PREFACE ................................................................................................................................ iv DECLARATION 1 – PLAGIARISM..................................................................................... v DECLARATION 2 – PUBLICATIONS ............................................................................... vi ACKNOWLEDGEMENTS ................................................................................................ viii TABLE OF CONTENTS ........................................................................................................ x LIST OF FIGURES ............................................................................................................. xiii LIST OF TABLES ................................................................................................................. xv CHAPTER 1 ............................................................................................................................. 1 Introduction .............................................................................................................................. 1 1.1 Indigenous forests ............................................................................................................ 1 1.2 Forests ecosystem services ............................................................................................... 5 1.3 Forests functional diversity and disturbance .................................................................... 7 1.4 Purpose of the study ....................................................................................................... 12 1.5 Study outline .................................................................................................................. 12 1.6 References ...................................................................................................................... 13 CHAPTER 2 ........................................................................................................................... 21 Occupancy of two forest specialist birds in the Southern Mistbelt Forests of KwaZulu- Natal and Eastern Cape, South Africa ................................................................................. 21 2.1 Summary ........................................................................................................................ 22 2.2 Introduction .................................................................................................................... 23 2.3 Methods .........................................................................................................................