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Dube K, Nhamo G. Evaluating climate Change's impact on hydroelectricity in the Zambezi river basin. Heliyon 2023; 9:e23235. [PMID: 38144288 PMCID: PMC10746471 DOI: 10.1016/j.heliyon.2023.e23235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/26/2023] Open
Abstract
This study investigates the effects of climate change on energy security in Africa, specifically focusing on the Upper and Lower Zambezi Basin. Data from the Kariba River basin sub-catchments, annual reports, the Climate Data Store, and Teal Tool Earth's country-by-country climate data were analysed through quantitative and qualitative data analysis techniques. The Mann-Kendal Trend Analysis was used to analyse time series and test the significance of changes to the climate. The historical climate and hydrological data analysis showed evidence of a slight increase in average rainfall amounts in the Zambezi River Basin but with high rainfall variability in some areas. Despite droughts increasing in frequency, there is a general increase in hydrological annual average water flow in the Zambezi River at two of the three sample sites. The increased water flow through the region could be attributed to population growth-induced land clearance and the degradation of wetlands in Angola's highlands. Although there is an increase in hydrological water flow into Kariba, there are water shortages for hydroelectricity generation due to increased generation capacity, resulting in increased demand for more water than in previous years. The unsustainable water abstraction to meet growing energy demands contributes to low water levels in the lake. The study recommends energy diversification and new hydroelectricity where the potential exists in the basin to reduce over-reliance on Lake Kariba with care not to disrupt the basin's hydrology and other economic activities. The study results provide insight into the potential effects of climate change on energy security in Africa.
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Affiliation(s)
- Kaitano Dube
- Ecotourism Management, Vaal University of Technology, Andries Potgieter BlvD, Vanderbijlpark, 1911, South Africa
| | - Godwell Nhamo
- Institute of Corporate Citizenship University of South Africa, Pretoria, South Africa
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Goyder DJ, Davies N, Finckh M, Gomes A, Gonçalves FMP, Meller P, Paton AJ. New species of Asclepias (Apocynaceae), Baphia (Leguminosae), Cochlospermum (Bixaceae) and Endostemon (Lamiaceae) from the Kalahari sands of Angola and NW Zambia, with one new combination in Vangueria (Rubiaceae). PHYTOKEYS 2023; 232:145-166. [PMID: 37780180 PMCID: PMC10534249 DOI: 10.3897/phytokeys.232.110110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/09/2023] [Indexed: 10/03/2023]
Abstract
Four new species are described from central and eastern Angola and adjacent NW Zambia. All occur in Kalahari sand savannas rich in endemic and more widely distributed geoxylic suffrutices. Despite being known from very few collections, the conservation status of one of these new species is assessed as Least Concern, as these grasslands are nutrient-poor, are in remote sparsely populated areas, and are not threatened with conversion to agriculture. The remaining three are treated as Data Deficient. In addition, one new combination is provided for Ancylanthosrubiginosus Desf. under Vangueria as V.rubiginosa (Desf.) Lantz is an illegitimate later homonym. We also make orthographic corrections to specific epithets commemorating Ilse von Nolde, a collector who made important collections from Quela in Malange in the 1930s.
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Affiliation(s)
- David J. Goyder
- Royal Botanic Gardens, Kew, TW9 3AE, London, UKNational Geographic Okavango Wilderness Project, Wild Bird TrustHogsbackSouth Africa
- National Geographic Okavango Wilderness Project, Wild Bird Trust, Hogsback, South AfricaRoyal Botanic Gardens, KewLondonUnited Kingdom
| | - Nina Davies
- Royal Botanic Gardens, Kew, TW9 3AE, London, UKNational Geographic Okavango Wilderness Project, Wild Bird TrustHogsbackSouth Africa
| | - Manfred Finckh
- Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, GermanyUniversity of HamburgHamburgGermany
| | - Amândio Gomes
- National Geographic Okavango Wilderness Project, Wild Bird Trust, Hogsback, South AfricaRoyal Botanic Gardens, KewLondonUnited Kingdom
- Natural Science Faculty of Agostinho Neto University, Luanda, AngolaNatural Science Faculty of Agostinho Neto UniversityLuandaAngola
| | - Francisco Maiato P. Gonçalves
- National Geographic Okavango Wilderness Project, Wild Bird Trust, Hogsback, South AfricaRoyal Botanic Gardens, KewLondonUnited Kingdom
- Herbarium of Lubango, ISCED-Huíla, Lubango, AngolaHerbarium of Lubango, ISCED-HuílaLubangoAngola
| | - Paulina Meller
- Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, GermanyUniversity of HamburgHamburgGermany
| | - Alan J. Paton
- Royal Botanic Gardens, Kew, TW9 3AE, London, UKNational Geographic Okavango Wilderness Project, Wild Bird TrustHogsbackSouth Africa
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Lourenco M, Woodborne S. Defining the Angolan Highlands Water Tower, a 40 plus-year precipitation budget of the headwater catchments of the Okavango Delta. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:859. [PMID: 37335410 DOI: 10.1007/s10661-023-11448-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 06/01/2023] [Indexed: 06/21/2023]
Abstract
Angola is a source of many major rivers in southern Africa and is referred to as the "water tower" of the region. The lack of a defined area delineating the Angolan Highlands water tower (AHWT) limits the conservation of this important freshwater source. This study hydrologically defines the boundary of the AHWT as areas > 1274 m above mean sea level within the Central Bié Plateau of Angola. Using the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) data, this study provides a 41-year precipitation budget of the AHWT and surrounding basins. Between 1981 and 2021, the average annual precipitation over the AHWT was 1112 mm and the gross annual average precipitation volume was approximately 423 km3 over an area of 380,382 km2. The AHWT is the southern source of the Congo Basin, the western source of the Zambezi Basin, and the sole water source of the endorheic Okavango Basin and Okavango Delta, a UNESCO World Heritage Site. On average, approximately 133 km3 (92.36%) of the gross annual precipitation volume for the headwater Cuito and Cubango catchments of the Okavango River is lost before reaching the Okavango Delta. Estimates of the annual flooding of the Okavango Delta during a 35-year period (1985-2019) were correlated to precipitation in the headwater catchments. Correlation coefficients are stronger for the entire rainfall season (0.76) and early rainfall season (0.62) for the combined Cuito-Cubango catchment in comparison to late rainfall season (0.50), which suggests that the antecedent conditions (first and second flood pulse) during the early rainfall season allows for greater Okavango Delta flood inundation. The correlation coefficients between the Cubango (0.72) and Cuito (0.78) Rivers and annual flood inundation are not significantly different (P > 0.05); however, these rivers have fundamental hydrological differences that influence the functioning of the Okavango Delta. The Cubango River, described as a flushing system, has much steeper gradient, more compact and shallow soils and flows faster with significant rapids, whereas the peatland rich, absorbent, seepage-driven baseflow of the Cuito River sustains the Okavango Delta during the dry season. The dynamics of seasonal precipitation, hydrology and climate change in the AHWT have important repercussions on water budgets, food security and biodiversity throughout southern Africa, requiring continued collaboration between countries to ensure that future development is sustainable.
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Affiliation(s)
- Mauro Lourenco
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg, South Africa.
- National Geographic Okavango Wilderness Project, Wild Bird Trust, Johannesburg, South Africa.
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Lourenco M, Woodborne S, Fitchett JM. Fire regime of peatlands in the Angolan Highlands. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 195:78. [PMID: 36342572 PMCID: PMC9638379 DOI: 10.1007/s10661-022-10704-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
The Angolan Highlands region includes the Angolan miombo woodland ecoregion which supports miombo woodland, grasslands, subsistence agricultural land, and peatland deposits. Extensive fires, slash and burn agriculture, peat fuel extraction, and peatland drainage are among the anthropogenic practices that threaten these peatland deposits. Peat fires cause peatland degradation, release significant amounts of greenhouse gases, deteriorate air quality, and contribute towards climate change and biodiversity loss. This study presents an analysis of the fire regimes over the period 2001 to 2020 in an under-studied area of the Angolan Highlands. Moderate Resolution Imaging Spectroradiometer (MODIS) fire and vegetation data were used in combination with a land use/land cover (LULC) classification map to calculate fire frequency, burn area, and fire regimes. The fire patterns within the study site are comparable to those found in African woodland savannas. Across the study site, 6976 km2 (11.31%) of the land surface area burned at least nine times from 2001 to 2020, occurring largely within in the river valley environment. Considering the different LULC classes, peatlands were calculated to (a) burn more frequently (average fire frequency from 2001 to 2020 = 9.12), (b) have the smallest proportion (4.11%) of area which remained unburnt over the fire archive, and (c) have the largest average proportion (45.65% or 746 km2) of burnt area per year. Peatland burning occurred predominantly during drier months from May to September. The results of this study highlight the strong influence of LULC on the fire frequency and distribution in the study area, requiring unique fire management strategies. As has been documented for boreal and tropical peatlands across the globe, we stress the importance of peatland conservation and protection; continued unsustainable management practices may lead to the loss of these important peatland deposits.
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Affiliation(s)
- Mauro Lourenco
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg, South Africa
- National Geographic Okavango Wilderness Project, Wild Bird Trust, Hogsback, South Africa
| | - Stephan Woodborne
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg, South Africa
- iThemba LABS, Private Bag 11, WITS, Johannesburg, South Africa
| | - Jennifer M. Fitchett
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg, South Africa
- BP012 Bernard Price Building, University of the Witwatersrand, Private Bag 3, Wits 2050 Johannesburg, South Africa
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Taylor PJ, Strydom E, Richards L, Markotter W, Toussaint DC, Kearney T, Cotterill FPD(W, Howard A, Weier SM, Keith M, Neef G, Mamba ML, Magagula S, Monadjem A. Integrative taxonomic analysis of new collections from the central Angolan highlands resolves the taxonomy of African pipistrelloid bats on a continental scale. Zool J Linn Soc 2022. [DOI: 10.1093/zoolinnean/zlac071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Ten years ago, the genus-level and species-level taxonomy of African pipistrelloid bats was in a state of flux. In spite of advances in the past decade, gaps in collecting from species-rich regions like Angola have hampered efforts to revise this group. We report on new collections of pipistrelle-like bats from the poorly sampled central highlands of Angola (1000–1500 m a.s.l.) as well as comparative material from lower-lying areas of Eswatini and South Africa. Specimens identified as Neoromicia anchietae, collected 400–700 km east of the holotype locality in the western highlands of Angola, were genetically and morphologically distinctive from N. anchietae s.l. from South Africa and Eswatini. We describe herein this latter lineage as a distinct species from low-lying areas of south-eastern Africa, distinct from N. anchietae s.s., which is therefore restricted to the central and western Angolan highlands. We also identified shallow to deep genetic divergence between different African regions in other recognized pipistrelloid species, such as conspecificity between the long-eared species Laephotis angolensis from Angola and Laephotis botswanae from northern Botswana, northern Namibia and south-western Zambia. Our phylogeny supports a recently proposed generic classification of African pipistrelloid bats.
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Affiliation(s)
- Peter John Taylor
- Afromontane Research Unit & Department of Zoology & Entomology, University of the Free State , Private Bag X13, Phuthaditjhaba 9866 , South Africa
- School of Mathematical & Natural Science, University of Venda , Thohoyandou, 0950 , South Africa
- Wild Bird Trust, National Geographic Okavango Wilderness Project , 27 Wolfridge Road, Hogsback 5721 , South Africa
| | - Erika Strydom
- Centre for Viral Zoonoses, Department of Medical Virology, University of Pretoria , Pretoria 0002 , South Africa
| | - Leigh Richards
- Durban Natural Science Museum , P.O. Box 4085, Durban 4000 , South Africa
| | - Wanda Markotter
- Centre for Viral Zoonoses, Department of Medical Virology, University of Pretoria , Pretoria 0002 , South Africa
| | - Dawn Cory Toussaint
- School of Mathematical & Natural Science, University of Venda , Thohoyandou , 0950, South Africa
- Wild Bird Trust, National Geographic Okavango Wilderness Project , 27 Wolfridge Road, Hogsback 5721 , South Africa
| | - Teresa Kearney
- Ditsong Natural History Museum , Pretoria 0002 , South Africa
- Department of Zoology and Entomology, University of Pretoria , Private Bag 20, Hatfield 0028, Pretoria , South Africa
| | - F P D (Woody) Cotterill
- Wild Bird Trust, National Geographic Okavango Wilderness Project , 27 Wolfridge Road, Hogsback 5721 , South Africa
- Geoecodynamics Research Hub, c/o Department of Botany and Zoology, University of Stellenbosch , Private Bag X1 Matieland, 7602, Stellenbosch , South Africa
| | - Alexandra Howard
- Afromontane Research Unit & Department of Zoology & Entomology, University of the Free State , Private Bag X13, Phuthaditjhaba 9866 , South Africa
| | - Sina Monika Weier
- Afromontane Research Unit & Department of Zoology & Entomology, University of the Free State , Private Bag X13, Phuthaditjhaba 9866 , South Africa
- School of Mathematical & Natural Science, University of Venda , Thohoyandou, 0950 , South Africa
- Wild Bird Trust, National Geographic Okavango Wilderness Project , 27 Wolfridge Road, Hogsback 5721 , South Africa
| | - Mark Keith
- Wild Bird Trust, National Geographic Okavango Wilderness Project , 27 Wolfridge Road, Hogsback 5721 , South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag 20, Hatfield 0028, Pretoria , South Africa
| | - Gӧtz Neef
- Wild Bird Trust, National Geographic Okavango Wilderness Project , 27 Wolfridge Road, Hogsback 5721 , South Africa
| | - Mnqobi L Mamba
- Department of Biological Sciences, University of Eswatini , Private Bag 4, Kwaluseni , Eswatini
| | - Siphesihle Magagula
- Department of Biological Sciences, University of Eswatini , Private Bag 4, Kwaluseni , Eswatini
| | - Ara Monadjem
- Department of Zoology and Entomology, University of Pretoria , Private Bag 20, Hatfield 0028, Pretoria , South Africa
- Department of Biological Sciences, University of Eswatini , Private Bag 4, Kwaluseni , Eswatini
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