Browsing by Author "Sosibo, Mbalenhle Thabile."

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Forest mammalian community dynamics and human wildlife interactions in the Southern Mistbelt Forests of KwaZulu-Natal and Eastern Cape, South Africa.
(2021) Sosibo, Mbalenhle Thabile.; Downs, Colleen Thelma.; Ehlers Smith, Yvette Cathrine.; Ehlers Smith, David Alan.
African and Asian forests are well known for their high faunal and floral diversity; however, many forests have been left degraded or cleared because of anthropogenic activities from the past and present. In particular, African forests have been heavily exploited for their timber resources and land conversion for anthropogenic activities such as agriculture,. South African forests, specifically the Southern Mistbelt Forests, have been subjected to heavy logging by colonial settlers and subsistence harvesting in recent times because of the logging of trees such as yellowwood species (Podocarpus and Afrocarpus spp.) and hunting of bushmeat species blue duiker (Philantomba monticola). The aim of the study was to assess the anthropogenic impacts on mammals occurring in the Southern Mistbelt forests of KwaZulu-Natal and Eastern Cape provinces, as well as other uses of the forest and human-wildlife interactions. Study areas included the disjunct Southern Mistbelt Forests of the northern Eastern Cape and southern KwaZulu-Natal provinces, South Africa. It was conducted in three different forest cluster areas: uMthatha, Glengarry/Weza [termed iNgeli hereafter] and Creighton with forest patches of varying size. We conducted camera-trap surveys between May 2018 – February 2019 during the wet (summer/spring) and dry (winter/autumn) seasons, resulting in one full 21-day survey for each camera-trap location per season. We used infrared motion detection camera-traps to monitor mammalian forest species at set camera-trap locations determined using a 400 m x 400 m systematic grid system overlaid onto Southern Mistbelt Forest patches in Arc GIS v10.5.1. We also conducted semi-structured interviews in all three areas from October to November 2019. When assessing microhabitat use by mammalian species, we found that mammalian species most often photographed during sampling seasons were bushbuck (Tragelaphus scriptus) and samango monkey (Cercopithecus albogularis labiatus), with the least photographed species being serval (Leptailurus serval) and African wild cat (Felis silvestris cafra). Land-use data around each forest patch were extracted, with settlements, exotic timber plantations and grasslands identified as the dominant adjacent land-uses. The importance of exotic tree plantations surrounding indigenous forest patches to the persistence of mammalian species was highlighted. The maturity and condition of exotic timber plantations surrounding forest patches in our study also varied and may have influenced the area's use and suitability by mammalian species. Creighton was the only study area where human settlements were a dominant land-use around patches. The samango monkey had the second highest mean occupancy across all sampling areas and land-use types. Forest mammals make considerable contributions to the functioning of forest ecosystems. We evaluated the response of forest mammal functional diversity and species richness to factors such as patch size. Species β-diversity was greatly driven by turnover and functional β- diversity was driven by nestedness; therefore, management implications of these forests and associated mammalian communities suggest that all patches should be considered a priority for conservation. Due to different management implications, if nestedness is dominant, forest patches that have a higher diversity of species traits and species richness should be prioritised for conservation. Lastly, we aimed to quantify and assess the dynamics of forest use and hunting of mammalian species in communities close to forest patches and found that ungulates are the preferred choice for consumption in lower-income settlements which is supported by many other studies. Different species were hunted for various reasons such as: consumption, monetary gain (bushmeat trade and selling of hides) as well as retaliatory killing of predators hunting livestock. However, respondents shared that the forests are important to them and to protect them guards would be a good choice as well as education and awareness about sustainable use. There is a paucity of information about the overall mammal community inhabiting these forests and this study has highlighted which species inhabit these forests as well as their forest utilisation and how anthropogenic activities affect species populations. Furthermore, it highlighted that communities close to these forests see these forests as areas of high conservation importance.
Response of estuarine and freshwater macroinvertebrate assemblages to habitat, water quality, flow and land use change in the lowland Amatikulu/Nyoni catchment.
(2018) Sosibo, Mbalenhle Thabile.; Downs, Colleen Thelma.; O'Brien, Gordon Craig.
Water has become a scarce commodity in Sub-Saharan Africa and in drought prone South Africa. Due to the extensive utilization of water resources in South Africa, management and monitoring of our rivers and estuaries is required by law to achieve a balance between use and protection. Macrobenthic invertebrates of estuaries and freshwater macroinvertebrates have played a large role as indicators of ecosystem health. The lowland Amatikulu/Nyoni catchment in the province of KwaZulu-Natal is relatively poorly understood and baseline information about the ecology of the ecosystem is required. This therefore advocates more research into the Amatikulu/Nyoni catchments ecological wellbeing is needed to inform best management practices. The overall aim of this study was to utilize aquatic macroinvertebrates as ecological indicators to evaluate the current biological condition of the Amatikulu/Nyoni River/Estuary. Freshwater and estuarine invertebrates were evaluated separately in the study with two main lines of evidence including: (1) the use of valid statistical methods to determine how water quality, habitat and sediment composition affected estuarine and freshwater macroinvertebrates community structure, abundance and distribution, and (2) the use of an established community metric measure or biological index namely the South African Scoring System (SASS) Version 5 to evaluate the wellbeing of the freshwater invertebrate communities. The application of these lines of evidence are detailed in chapters two and three. Chapter one is a general introduction for the thesis and a comprehensive literature review of how and why macroinvertebrates have been used as a bio indicators of freshwater and estuarine integrity. Chapter two describes the collection of freshwater macroinvertebrates from four freshwater sites and their assessment using the SASS5 community metric measure during the high and low flow seasons in 2017. In addition, multivariate statistical analyses were performed on the data to test the significance of macroinvertebrate community shifts and correlations with changes in temperature, conductivity, dissolved oxygen, percentage dissolved oxygen, pH, South African Scoring System Version 5 Scores, Average Score Per Taxa (ASPT), the number of individuals for each survey and flow periods and between sites. The lowland Amatikulu River catchment sites showed that there was a change in the ecological condition of freshwater macroinvertebrate assemblages as well as along a longitudinal gradient with upstream sites having better conditions to support more sensitive species. In the third chapter, estuarine benthic macroinvertebrates were collected from four estuary sites using a Van Veen grab during two sampling surveys in 2017. To analyse the data, Conoco version 4.5 was also used to test the significance of benthic invertebrate community shifts and correlations with environmental, spatial and temporal variables. Estuarine benthic invertebrate assemblages varied between sampling sessions in accordance with estuary mouth conditions, nutrient concentrations, sediment grain size distributions and total organic content levels compared with other environmental parameters. By identifying the relationship and drivers between aquatic macroinvertebrates with water quality, habitat, flow and anthropogenic land use change, insight has been gained into the structure and function of the Amatikulu/Nyoni Catchment, its ecosystem health and some management and monitoring recommendations derived to contribute to the sustainable management of the system.