Distribution and habitat preferences of marine megafauna in Nosy Be, Madagascar
- Authors: Lubbé, Alicea
- Date: 2023-10-13
- Subjects: Marine animals Habitat Madagascar Nosy Be , Marine animals Geographical distribution Madagascar Nosy Be , Species distribution modelling , Maximum entropy method , Citizen science , Habitat preference
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424710 , vital:72177
- Description: Marine megafauna have important ecological roles including the top-down regulation of lower trophic levels and the transport of nutrients. They are also charismatic species of socioeconomic importance, due to their public appeal and focus for ecotourism. However, these taxa face numerous anthropogenic threats including bycatch, habitat-loss, noise disturbance, prey reductions, pollution, and vessel traffic. Northwest Madagascar has been identified as an important marine mammal area and whale shark aggregation site, yet limited information on megafauna within Madagascar exists. In this thesis, I investigated the community structure, distribution trends, related environmental factors (Chapter 2) and predicted habitat suitability (Chapter 3) using a species distribution modelling approach for marine megafauna around Nosy Be, North-west Madagascar. Data collection consisted of opportunistic boatbased surveys conducted while looking for whale sharks, mobulid rays and cetaceans. These activities were performed by dedicated ‘swim with whale shark’ tourism operators, Les Baleines Rand'eau and Safari Baleine during tourism activities directed by the Madagascar Whale Shark Project over four years (2016-2019). A total of 1792 sightings were reported with 13 identified species, including elasmobranchs: whale shark, Rhincodon typus; spinetail mobula ray, Mobula japonica; giant oceanic manta ray, Manta birostris; shortfin devil ray, Mobula kuhlii; balaenids: humpback whale, Megaptera novaeangliae; Omura's whale, Balaenoptera omurai, delphinids: Indo-Pacific bottlenose dolphin, Tursiops aduncus; spinner dolphin, Stenella longirostris; pantropical spotted dolphin, Stenella attenuata; Indian ocean humpback dolphin, Sousa plumbea; false killer whale, Pseudorca crassidens; melonheaded whale, Peponocephala electra and one cheloniid species: leatherback sea turtle, Dermochelys coriacea. Sightings were spatially analysed at a community level according to feeding guilds (i.e., filter feeders vs. predators), and distribution of the megafauna groups v were compared to selected remotely sensed physico-chemical data (sea surface temperature and chlorophyll-a concentration) and bathymetry charts (depth and slope) using generalized linear models (Chapter 2). All four variables had a significant effect on filter feeder distribution. Spatial distribution of filter feeder sightings peaked at an area of steep underwater topography (18-50m; x slope=0.5%) located on the west coast of Nosy Be, where foraging aggregations of large filter feeders (primarily R. typus and B. omurai) were frequently observed. Only SST had a significant effect on the relative abundance of animals in the predator feeding guild, which demonstrated a more longitudinal distribution along the continental shelf. The maximum entropy model (Maxent) was used for predicting habitat preference for the most frequently sighted species (Chapter 3). The distribution of whale sharks, mobulid rays and Omura’s whales were significantly overlapped as they were abundant in two main hotspots, Grand banc de l’entrée (~10 km of the west coast) and near Nosy Mitsio island, (~50 km northeast of Nosy Be). Suitable habitat for the dolphins was in relatively shallow waters in temperatures <28ºC near areas of steep changes in bathymetry. Bottlenose and spinner dolphins had a more widespread distribution across the continental shelf and humpback dolphin was closely associated with inshore reefs and occur in waters <10m. The coastal and inshore region of Nosy Be is an important habitat for a variety of megafaunal species, and the continental shelf provided essential areas for feeding and breeding. The results were similar to those presented for these species in other regions of the Indian Ocean (i.e., Eastern and Southern Africa; Western Australia; Seychelles) as well as outside of the Indian Ocean (i.e., Indonesia; Caribbean; North Atlantic). Thus the results from this thesis could be considered for management recommendations for marine conservation in the region. The value and limitations of data collected by citizen science were outlined (Chapter 4). , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Lubbé, Alicea
- Date: 2023-10-13
- Subjects: Marine animals Habitat Madagascar Nosy Be , Marine animals Geographical distribution Madagascar Nosy Be , Species distribution modelling , Maximum entropy method , Citizen science , Habitat preference
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424710 , vital:72177
- Description: Marine megafauna have important ecological roles including the top-down regulation of lower trophic levels and the transport of nutrients. They are also charismatic species of socioeconomic importance, due to their public appeal and focus for ecotourism. However, these taxa face numerous anthropogenic threats including bycatch, habitat-loss, noise disturbance, prey reductions, pollution, and vessel traffic. Northwest Madagascar has been identified as an important marine mammal area and whale shark aggregation site, yet limited information on megafauna within Madagascar exists. In this thesis, I investigated the community structure, distribution trends, related environmental factors (Chapter 2) and predicted habitat suitability (Chapter 3) using a species distribution modelling approach for marine megafauna around Nosy Be, North-west Madagascar. Data collection consisted of opportunistic boatbased surveys conducted while looking for whale sharks, mobulid rays and cetaceans. These activities were performed by dedicated ‘swim with whale shark’ tourism operators, Les Baleines Rand'eau and Safari Baleine during tourism activities directed by the Madagascar Whale Shark Project over four years (2016-2019). A total of 1792 sightings were reported with 13 identified species, including elasmobranchs: whale shark, Rhincodon typus; spinetail mobula ray, Mobula japonica; giant oceanic manta ray, Manta birostris; shortfin devil ray, Mobula kuhlii; balaenids: humpback whale, Megaptera novaeangliae; Omura's whale, Balaenoptera omurai, delphinids: Indo-Pacific bottlenose dolphin, Tursiops aduncus; spinner dolphin, Stenella longirostris; pantropical spotted dolphin, Stenella attenuata; Indian ocean humpback dolphin, Sousa plumbea; false killer whale, Pseudorca crassidens; melonheaded whale, Peponocephala electra and one cheloniid species: leatherback sea turtle, Dermochelys coriacea. Sightings were spatially analysed at a community level according to feeding guilds (i.e., filter feeders vs. predators), and distribution of the megafauna groups v were compared to selected remotely sensed physico-chemical data (sea surface temperature and chlorophyll-a concentration) and bathymetry charts (depth and slope) using generalized linear models (Chapter 2). All four variables had a significant effect on filter feeder distribution. Spatial distribution of filter feeder sightings peaked at an area of steep underwater topography (18-50m; x slope=0.5%) located on the west coast of Nosy Be, where foraging aggregations of large filter feeders (primarily R. typus and B. omurai) were frequently observed. Only SST had a significant effect on the relative abundance of animals in the predator feeding guild, which demonstrated a more longitudinal distribution along the continental shelf. The maximum entropy model (Maxent) was used for predicting habitat preference for the most frequently sighted species (Chapter 3). The distribution of whale sharks, mobulid rays and Omura’s whales were significantly overlapped as they were abundant in two main hotspots, Grand banc de l’entrée (~10 km of the west coast) and near Nosy Mitsio island, (~50 km northeast of Nosy Be). Suitable habitat for the dolphins was in relatively shallow waters in temperatures <28ºC near areas of steep changes in bathymetry. Bottlenose and spinner dolphins had a more widespread distribution across the continental shelf and humpback dolphin was closely associated with inshore reefs and occur in waters <10m. The coastal and inshore region of Nosy Be is an important habitat for a variety of megafaunal species, and the continental shelf provided essential areas for feeding and breeding. The results were similar to those presented for these species in other regions of the Indian Ocean (i.e., Eastern and Southern Africa; Western Australia; Seychelles) as well as outside of the Indian Ocean (i.e., Indonesia; Caribbean; North Atlantic). Thus the results from this thesis could be considered for management recommendations for marine conservation in the region. The value and limitations of data collected by citizen science were outlined (Chapter 4). , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
- Full Text:
- Date Issued: 2023-10-13
The potential of social learning to upscale the Community Based Water Quality Management (CBWQM) process: A case study of the Mpophomeni and Baynespruit Enviro Champs project
- Authors: Sithole, Nkosingithandile
- Date: 2023-10-13
- Subjects: Community of practice , Social learning , Water quality management South Africa Pietermaritzburg Citizen participation , Citizen science , Water quality South Africa Pietermaritzburg
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/402966 , vital:69910
- Description: Water is an essential component of human survival, with a wide variety of uses such as washing, cooking, drinking and growing food. Covering approximately 70% of the Earth’s surface, water is necessary for all human survival, and is a source of life for plants and animals. Only 0.036% of freshwater can be accessed and utilised by humans, which is not enough to support the rapidly growing population and economic development. This water is further exhausted by pollution caused by sewage leaks, littering, agricultural runoff and industry discharge which deteriorate water quality significantly. To exacerbate these water issues, the major issue of water accessibility is not directly linked to quantity but has been primarily attributed to poor water governance, at a global and local level (in South Africa). Poorly maintained water infrastructure and inadequate cooperative governance have resulted in the establishment of many Community Based Water Quality Management (CBWQM) projects in South Africa, to respond to water quality monitoring and management challenges. The aim of this study was firstly, to investigate how social learning was occurring within two CBWQM Communities of Practice (CoPs) located in KwaZulu-Natal, Pietermaritzburg, namely, the Baynespruit and the Mpophomeni Enviro Champs project (Case Study 1 and 2 respectively), and the potential of social learning to upscale CBWQM. Additionally, it sought to identify the type of support required for the scaling of social learning outcomes in CBWQM communities of practice, along two potential scaling pathways that were identified in a national study on scaling of CBWQM: Scaling Pathway 1(Policy engagement and support) and Scaling Pathway 2 (Capacity building). The research was undertaken as a qualitative case study approach, with data collected through semi-structured interviews, document, and questionnaire analysis to investigate social learning within the two selected case studies. The data was coded and indexed using a thematic analysis technique and an analytical framework as a tool to investigate how social learning was occurring in both case studies and explore the potential required to upscale it. The study found that there is an existing gap between policy and practice with regard to CBWQM support by government structures. Despite South African water policy advocating for public participation in water resource management, there has been limited support from government to support and resource CBWQM projects over a long period of time. To upscale the practice of CBWQM, the study found that capacity building and learning needs to be improved and better supported practically through models such as the 5Ts of learning, and through supporting CBWQM participants’ learning journey to establish learning pathways for them. , Thesis (MEd) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Sithole, Nkosingithandile
- Date: 2023-10-13
- Subjects: Community of practice , Social learning , Water quality management South Africa Pietermaritzburg Citizen participation , Citizen science , Water quality South Africa Pietermaritzburg
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/402966 , vital:69910
- Description: Water is an essential component of human survival, with a wide variety of uses such as washing, cooking, drinking and growing food. Covering approximately 70% of the Earth’s surface, water is necessary for all human survival, and is a source of life for plants and animals. Only 0.036% of freshwater can be accessed and utilised by humans, which is not enough to support the rapidly growing population and economic development. This water is further exhausted by pollution caused by sewage leaks, littering, agricultural runoff and industry discharge which deteriorate water quality significantly. To exacerbate these water issues, the major issue of water accessibility is not directly linked to quantity but has been primarily attributed to poor water governance, at a global and local level (in South Africa). Poorly maintained water infrastructure and inadequate cooperative governance have resulted in the establishment of many Community Based Water Quality Management (CBWQM) projects in South Africa, to respond to water quality monitoring and management challenges. The aim of this study was firstly, to investigate how social learning was occurring within two CBWQM Communities of Practice (CoPs) located in KwaZulu-Natal, Pietermaritzburg, namely, the Baynespruit and the Mpophomeni Enviro Champs project (Case Study 1 and 2 respectively), and the potential of social learning to upscale CBWQM. Additionally, it sought to identify the type of support required for the scaling of social learning outcomes in CBWQM communities of practice, along two potential scaling pathways that were identified in a national study on scaling of CBWQM: Scaling Pathway 1(Policy engagement and support) and Scaling Pathway 2 (Capacity building). The research was undertaken as a qualitative case study approach, with data collected through semi-structured interviews, document, and questionnaire analysis to investigate social learning within the two selected case studies. The data was coded and indexed using a thematic analysis technique and an analytical framework as a tool to investigate how social learning was occurring in both case studies and explore the potential required to upscale it. The study found that there is an existing gap between policy and practice with regard to CBWQM support by government structures. Despite South African water policy advocating for public participation in water resource management, there has been limited support from government to support and resource CBWQM projects over a long period of time. To upscale the practice of CBWQM, the study found that capacity building and learning needs to be improved and better supported practically through models such as the 5Ts of learning, and through supporting CBWQM participants’ learning journey to establish learning pathways for them. , Thesis (MEd) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-10-13
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