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COPYRIGHT AND CITATION CONSIDERATIONS FOR THIS THESIS/ DISSERTATION o Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. o NonCommercial — You may not use the material for commercial purposes. o ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original. How to cite this thesis Surname, Initial(s). (2012) Title of the thesis or dissertation. PhD. (Chemistry)/ M.Sc. (Physics)/ M.A. (Philosophy)/M.Com. (Finance) etc. [Unpublished]: University of Johannesburg. Retrieved from: https://ujcontent.uj.ac.za/vital/access/manager/Index?site_name=Research%20Output (Accessed: Date). Characterizing selected invasive plants in the Klipriviersberg Nature Reserve using field based spectroradiometer data By: Bambo Dubula (201378775) A Minor Dissertation submitted in partial fulfilment of the degree of MSc in Environmental Management in the Department of Geography, Environmental Management and Energy studies. In the Faculty of Science At the University of Johannesburg Supervisor: Dr Solomon G. Tefsamichael Co-Supervisor: Dr Isaac T. Rampedi October 2015 Abstract The Klipriviersberg Nature Reserve has proportionally large number of invasive plant species (Morné Britz, personal communication). Management of these species currently focuses on conspicuous woody species and less attention is placed on smaller plant species that are likely to threaten biodiversity. This can potentially result in more costly and labour intensive management programmes if imminent environmental threats are not timeously identified. The use of timely spatial distribution maps aids in improving invasive plant management strategies. Invasive plant distribution maps have been developed using traditional mapping methods; but these are costly and time consuming. Remote sensing techniques on the other hand have shown the potential in characterizing invasive plants species in different studies. This study aimed to extend this potential by discriminating selected invasive plant species, namely, Artemisia afra, Asparagus laricinus and Seriphium plumosum from adjacent land cover types using continuum spectra of a field spectrometer data. In addition, the study aimed to investigate the use of spectra simulated according to bands of SPOT and Landsat images in an effort to explore the potential of extending field based analysis to airborne or spaceborne remote sensing systems. Data were analysed at individual, plot and group levels, respectively. Results showed A. afra and A. laricinus to be best discriminated from adjacent land cover types using the near infrared (NIR) region from analysis using both original and simulated spectra. None of the regions that were assessed for S. plumosum, however, did show the potential of discriminating the species from grass using both the original and simulated spectra. Successful discrimination of A. afra and A. laricinus from adjacent land cover types using simulated bands shows the potential of upscaling field based techniques, particularly the NIR region, to spaceborne and airborne remote sensing technologies such as SPOT and Landsat. Further studies are, however, recommended to improve the reliability of the findings obtained in this study. Such studies would need to address the shortcomings encountered in this study by (1) using more samples, (2) categorising data analysis according to plant phonological stages to help determine best timing for discrimination of the species, and (3) taking of spectral measurements under ideal environmental conditions. Studies on biochemical composition of the species are also encouraged to inform on reflectance behaviours of the species as plant compounds or pigments influence electromagnetic reflectance differently. i Acknowledgements I would like to give thanks to the almighty GOD for making this research work successful. I would like to extend my sincere gratitude to my supervisor, Dr. Solomon G. Tesfamichael for all the time, dedication and consistent guidance put in throughout the course of this work. You were at all times available and keen to offer assistance with patience when needed. The work you have done has been more than supervision, you put in a massive effort, which is deeply appreciated. Even though I had little knowledge in the field of remote sensing, I am now more confident to continue in the field. The time you invested in this research since data collection to the last stages of the research has made this journey exciting and a success. Your kind-heartedness humbles me, and I wish that you pass this on to other students as well. I give special thanks to my Co-Supervisor Dr. Isaac T. Rampedi for research expertise provided in this work, for continuous encouragements and partaking in data collection. I am grateful to the manager of the Klipriviersberg Nature Reserve, Mr Bishop Ngobeli, and his team for permitting use of the reserve as a study site as well as allocating dedicated staff members during the entire field survey. In this regard, I would like to thank Bongeka Wendy Mbatha and Minenhle Gumede for their guidance throughout the field campaign. It is heart-warming to find people like them with incredible experience and knowledge of locating all the vegetation types in the reserve accurately. I hold the highest gratitude to my father Mr Lordverse Mthobi Dubula and my mother Mrs Antonia Koleka Dubula for believing in me, for giving me guidance, encouragement and for all the support they have given me throughout my education. It is a great honour to be raised by loving and caring parents. You have nourished me since childhood, raised me and taught me well. This research would not have been a success without respect, discipline and endurance. The support of my siblings, colleagues and friends is highly appreciated. More gratitude is expressed to the University of Johannesburg for sponsoring my field work through funding and equipment use. Last, my heartfelt appreciation goes to Gold Fields South Deep for sponsoring my studies. Your support is highly acknowledged. You are making a huge difference in promoting South African education and in uplifting previously disadvantaged students. ii Table of Contents CHAPTER 1: Introduction 1.1 Background ....................................................................................................... 1-2 1.2 Research problem statement ............................................................................ 2-4 1.3 Research question ............................................................................................... 4 1.4 Aims and objectives ............................................................................................. 5 1.5 Significance of the study ...................................................................................... 5 1.6 Structure of the dissertation .............................................................................. 5-6 CHAPTER 2: Literature review 2.1 Introduction .......................................................................................................... 7 2.2 An overview of South Africa’s biodiversity ......................................................... 7-8 2.3 Indigenous plants of South Africa and their benefits ......................................... 8-9 2.4 Drivers and behaviors of invasive plant species and threats posed on indigenous vegetation ............................................................................................................ 9-11 2.5 Efforts to control invasive plants in South Africa ........................................... 11-12 2.6 Remote sensing of invasive plant species ..................................................... 12-14 2.6.1 Multispectral remote sensing for characterizing invasive plant species .. 14-18 2.6.2 Hyperspectral remote sensing for characterizing invasive plant species . 19-23 2.8 Summary ............................................................................................................ 24 CHAPTER 3: Discrimination of Artemisia afra from surrounding land cover types using field spectrometer Abstract .................................................................................................................... 25 3.1 Introduction ................................................................................................... 26-29 3.2 Methods ........................................................................................................ 29-36 3.2.1 Study area ............................................................................................... 29-30 3.2.2 Field data ................................................................................................ 30-31 3.2.3 Analysis of spectral reflectance per region .............................................. 32-35 3.2.4 Simulation of Landsat and SPOT 5 imagery bands...................................... 36 3.3 Results .......................................................................................................... 36-41 3.3.1 Reflectance properties per region ........................................................... 36-39 iii 3.3.2 Landsat simulation .................................................................................. 39-40 3.3.3 SPOT 5 simulation .................................................................................