Afrotropical Streams and Rivers

Structure, Ecological Processes and Management

1st Edition - November 9, 2024
Editors: Tatenda Dalu, Frank Masese
Language: English
Paperback ISBN:
9 7 8 - 0 - 4 4 3 - 2 3 8 9 8 - 7
eBook ISBN:
9 7 8 - 0 - 4 4 3 - 2 3 8 9 7 - 0

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The Afrotropical Streams and Rivers: Structure, Ecological Processes and Management is a comprehensive guide that provides assessment of major rivers and tributaries in Africa. Unlike other books available, the editors present a thorough study of geomorphological, hydrological, biological, and ecological processes incorporating a range of plant and animal communities, while considering implications of human communities that depend upon them. This book, edited by a diverse cohort of researchers and/or scholars, is intended as an educational and practical guide for graduate students, researchers and scientists who focus on the biodiversity, conservation and management/policy issues of the African river systems.

Title of Book
Cover image
Title page
Table of Contents
Copyright
Dedication
Contributors
About the authors
Foreword
The scope of this compilation
Regional studies: Detailed exploration of key river systems
Key ecological processes
Ecosystem functioning and biodiversity
Flora and fauna
Management and conservation
Contemporary challenges
Restoration and future directions
Preface
Acknowledgments
Chapter 1. African streams and rivers: An introduction
Overview
Introduction to streams and rivers
Defining characteristics of African streams and rivers
Biophysical attributes
Transboundary nature of water resources
Hydrology and climate
Biodiversity
Urbanization and infrastructure development
Agriculture
Ecological significance
Cultural relevance
High dependency on streams and rivers
Importance of African streams and rivers
Threats to streams and rivers
Climate change: A looming specter
Habitat degradation: A fragmented landscape
Invasive species: Uninvited guests
Pollution: A toxic cocktail
Population growth: A growing demand
Overharvesting/overexploitation: An unsustainable practice
Land use and land cover change
Sustainable use of streams and rivers
Structure of the book
Conclusion
Section I. Major river systems and associated tributaries
Chapter 2. Major African river systems and their associated tributaries: An overview
Introduction
Biogeographical setting
Paleogeography and physiography
Climate
Geomorphology and hydrology
Unique aquatic biota and riparian biodiversity
Management and conservation
Major rivers and minor tributaries
Conclusion
Chapter 3. Rivers of southern Africa
Introduction
The mighty Zambezi River Basin
Eastern Coastal Rivers
Limpopo River Basin
South-eastern Coastal Rivers
South-western Coastal Rivers
Orange-Senqu River Basin
Namibian Coastal Rivers
Angolan Coastal Rivers
Interior Rivers
Conclusion
Chapter 4. Rivers of East Africa
Introduction
Biogeographical setting
Paleogeography and physiography
Climate
Geomorphology and hydrology
Unique aquatic and riparian biodiversity
Fish
Benthic macroinvertebrates
Mammals
Reptilians and amphibians
Plants
Management and conservation
Major rivers and minor tributaries
Kagera River
Mara River
Ruvu River
Nile River
Rufiji River
Tana River
Ruzizi River
Conclusions and perspectives
Chapter 5. Rivers of the Congo Basin in Central Africa
Introduction
Climate in the Congo River Basin
Physiography
Paleogeography
Hydrology and hydraulics
Water quality and material transport
Freshwater biodiversity in the Congo River Basin
Selected major rivers
Kasai River
Aruwimi River
Ubangi River
Sangha River
Selected minor rivers
Lulonga River
Lukuga River
Lualaba River
Ulindi River
Djoué River
Lubudi River
Management and conservation of the Congo River Basin
Chapter 6. Rivers of West Africa
Introduction
Physiography
Climate
Paleogeography
Biogeography
Major rivers and minor rivers
Major rivers
Senegal river
Volta river
Niger river
Gambia river
Minor rivers
Mano river
Cavalla river
Bandama river
Sourou river
Black Volta river
Pendjari (Oti) river
Benue river
Komoé (Comoe) river
Geomorphology and hydrology
Threats
Dams
Deforestation
Climate change
Water pollution
Overuse, overharvesting, and overexploitation
Invasive species
Conservation
Chapter 7. Rivers of North Africa
Introduction
Physiography
Climate
Paleogeography
Biogeography
Centers of species richness in North Africa
Patterns of macroinvertebrate diversity in North African rivers
Unique aquatic and riparian organisms
Freshwater fish
The Dades trout (Salmo multipunctate)
Odonata biodiversity
Major rivers and minor rivers
Geomorphology and hydrology
The Sebou River
The Chaliff River basin
The Bou Regreg River
The Drâa River basin
The Moulouya River basin
The Oum Er-Rbia basin
The Nile River
Threats
Water pollution
Water abstraction and development
Overexploitation/overharvesting
Climate change
Invasive species
Conservation
Conclusion
Section II. Physical structure and ecological processes
Chapter 8. Erosion and accretion—Landscape sculpting by water
Introduction
The upper course
The middle and lower courses
A river drainage basin
Inputs
Processes
River erosion
Accretion
A case study of the Limpopo River
Concluding remarks
Chapter 9. African river hydrology
Introduction
Overview of the hydrological cycle
Factors influencing African river hydrology
Precipitation
Evaporation
Infiltration
Water balance in African river systems
Major African river systems
Hydrological river basins in Africa
Nile River basin
Congo River basin
Juba–Shabelle River basin
Lake Chad basin
Limpopo River basin
Niger River basin
Ogooue River basin
Orange River basin
Senegal River basin
Volta River basin
Zambezi River basin
Conclusion
Chapter 10. The physicochemical environment
Introduction
Drivers of physicochemical parameters in streams and rivers
Natural drivers of water quality in streams and rivers
Climate
Geology and soil type
Hydrological flowpaths
Elevation
Land cover
Stream size
Large wildlife
Anthropogenic drivers
Land use and land cover changes
River damming
Temporal variability is water physicochemistry
Subdaily variation
Daily variation
Seasonality
Interannual variability
Case studies
Catchment-scale patterns in water quality physicochemical parameters in the MRB
Spatiotemporal patterns in physicochemical parameters
Land use–dependent concentration–discharge relationships in the Sondu Basin, Kenya
Knowledge gaps and future directions
Conclusions
Chapter 11. River riparian zones in Sub-Saharan Africa: Processes, functions, and sustainability
Introduction
Riparian zone processes and functions
Introduction to riparian zones in sub-Saharan Africa
Flood attenuation function
Floodplain degradation
Riparian zones and ecosystem services
Ecosystem services
The evolution of land use in riparian zones in South Africa
Anthropogenic riparian zone degradation
Threats to riparian systems
Trend of ASM in the riparian zone of Ulindi River
Vegetation changes in the riparian zone
Water quality assessment
Causes of ASM on the Ulindi river
Synthesis
Conclusions and recommendations
Chapter 12. Organic matter dynamics
Introduction
Different fractions of organic matter
Dissolved organic matter
Particulate organic matter
Sources and inputs of organic matter in rivers
Sources and inputs of particulate organic matter
Sources and inputs of dissolved organic matter
Role of large mammalian herbivores in organic matter inputs in rivers
Quantity of organic matter in rivers
Dynamics and drivers of organic matter inputs in rivers
Processing of organic matter
Litter decomposition
Role of detritivorous shredders
Influence of litter quality
Leaf litter decomposition and the ecological condition of streams
Influence of land use on organic matter decomposition
Organic matter transport fluxes in rivers
Influence of human activities on organic matter dynamics
Characterization of dissolved organic matter in rivers
Fluorescence spectroscopy
Excitation and emission matrices
Fluorescence indices
Ultra violet visible spectroscopy
Size exclusion chromatography
Nuclear magnetic resonance high-performance liquid chromatography
Fourier-transform ion cyclotron resonance mass spectrometry
Gaps in knowledge and challenges
Conclusions
Chapter 13. Primary production and ecosystem metabolism
Introduction
Primary production and metabolism of Afrotropical streams
Are Afrotropical streams metabolically different from other streams?
Human impacts on stream metabolism in Africa
Chapter 14. Land–water connections from river source to mouth
Introduction
Land-water connections in stream ecology
Unique aspects of Afrotropical streams and rivers
Anthropogenic impacts on land-water connections
Chapter overview
Forested headwaters
Overview
Africa's water towers
Kenya case study
Mount Kenya
Aberdare ranges
Mount Elgon
Cherangany Hills
Threats and challenges to Kenyan water towers
Case study of forested headwater connectivity in Kenya—The Mau Forest Complex
Savannah grasslands
Overview
Role of fire
Large wildlife
Livestock grazing
Climate change
Case study of greater Serengeti-Mara ecosystem
Wetland ecosystems
Overview
Key wetland ecosystems in Africa
Headwater catchment wetlands
Coastal wetlands
Case study of the Mara River and floodplain wetland in Kenya-Tanzania
Overview of Uganda wetland ecosystems
Lake Wamala wetland system
Lake Kyoga wetland system
Lake Albert wetland system
Lake Edward wetland system
Achwa wetland system
Victoria Nile wetland system
Lake Victoria wetland system
Drivers of wetland degradation
Wetland restoration and conservation mechanisms
Conclusion
Section III. Biota
Chapter 15. Microbes and phytoplankton
Introduction
Diversity and composition of microbes in African river systems
Bacteria
Proteobacteria
Bacteroidetes
Firmicutes
Actinobacteria
Verrucomicrobia
Acidobacteria
Planctomycetes
Acinetobacter
Fungi
Viruses
Bacteriophages
Enteric viruses
Rotaviruses
Significance of phytoplankton in freshwater ecosystems
Cyanobacteria (blue-green algae)
Chlorophyta (green algae)
Bacillariophyceae (diatoms)
Other algae
Euglenoids
Xanthophyta
Dinoflagellates
Cryptophyta
Rhodophyta
An overview of phytoplankton communities in African rivers
Environmental factors shaping phytoplankton distribution and abundance
Nutrient availability
Water temperature
Light availability
Hydrographic conditions
Presence of macrophytes
Trophic interactions
Phytoplankton as bioindicators for water quality and ecosystem health
Challenges and opportunities in Afrotropical phytoplankton research
Conclusions
Chapter 16. Macrophytes
Introduction
Distribution and habitat
North Africa
West Africa
East Africa
Central Africa
Southern Africa
Adaptation and morphology
Morphological adaptation
Emergent macrophytes
Floating macrophytes
Submerged macrophytes
Adaptation to salinity and water chemistry tolerance
Adaptation to water level fluctuations
Reproductive adaptation
Macrophytes ecological roles
Threats and conservation
North Africa
West Africa
East Africa
Central Africa
Southern Africa
Conclusions
Chapter 17. Macroinvertebrates
Introduction
Taxonomy and zoogeography
Major taxonomic groups
Ephemeroptera
Trichoptera
Mollusca
Odonata
Plecoptera
Coleoptera
Hemiptera
Diptera
Crustacea
Minor macroinvertebrate groups
Porifera
Cnidaria
Lepidoptera
Megaloptera and Neuroptera
Annelida-Oligochaeta
Arachnida-Acarina
Factors influencing macroinvertebrate diversity and distribution
Natural factors
Geomorphology
Climate
Elevation
Stream size or order
Macroinvertebrate ecology
Habitat and biotope preferences
Functional organization
Classification of macroinvertebrates into functional feeding groups (FFGs)
Macroinvertebrate traits
Classification and representation of traits
Effects of human activities on riverine macroinvertebrates
Urbanization and industrial activities
Agriculture
Deforestation
River damming
Use of macroinvertebrates in biomonitoring
Biotic indices
Functional indices
Macroinvertebrate functional feeding groups
Functional traits
Conclusions and future directions
Chapter 18. Fishes of southern Africa
Introduction
Anguillid eels
Cyprinid minnows, mudfish, and yellowfish
Siluriform catfishes
Characins tigerfish and minnows
Mormyrid snout fishes
Cichlids
Uncommon families
Protoperidae lungfish
Kneriidae earfishes
Galaxiidae
Cyprinodontiformes
Anabantidae labyrinth fishes
Mastacembelidae spiny eels
Environmental preferences of fishes and their conservation status
Fisheries and social-cultural aspects
Conclusion
Chapter 19. Birds, mammals, reptiles, and amphibians
Introduction
Patterns of species diversity in Afrotropical rivers
Avifauna
Mammals
Reptiles
Amphibians
Patterns across taxa
Seasonal fluctuations
African rivers as drivers of speciation
Conservation and challenges
Conclusion
Chapter 20. Food web dynamics
Introduction and overview
Trophic groups
Primary production
Detritivory and herbivory
Secondary and tertiary consumers
Models and approaches used to quantify trophic interactions
Functional trait, diversity and responses
Gut contents analysis
Use of biomarkers in food webs
Use of fatty acids
Use of stable isotopes
Use of DNA-based methods
Influence of river typology on trophic dynamics
Headwater streams
Large rivers
Dryland rivers
Influence of seasonality
Are Afrotropical streams and rivers different?
Relative importance of trophic resources
Allochthony
Autochthony
Dominance of macroconsumers
Widespread omnivory
Food chain length
Terrestrial-river connectivity
Effects of human activities on African riverine food webs
Land use and land cover changes
Exotic introductions
Climate change
Loss of river connectivity
Knowledge gaps and future research needs
Conclusion
Section IV. Management, conservation, and threats
Chapter 21. Management and governance of African rivers
Introduction
Management and governance of river basins
Scales of river basin management and governance
Local scale: Community-based river basin management
Subnational/regional scale: River basin authorities
National scale: Centralized river basin governance
Transboundary scale: International cooperation
International scale: Global cooperation and partnerships
Management issues in Africa's river basins
Transboundary nature of water resources
Inadequate monitoring
Inadequate funding
Limited data on river discharge
Existing management and governance structures in Africa
Institutional structures for the management of river basins in Africa
Local level
National level
Transboundary level
Policy and legal frameworks for the governance of rivers in Africa
Challenges in the management and governance of river basins in Africa
Failures of existing institutional and legal frameworks
Emerging issues
Politics in water resources management
Limited integration across sectors
Limited financial resources
Strategies for effective management and governance of African rivers
Harmonization of management and governance structures
Traditional approaches
Participatory approaches
Development of cost-effective monitoring tools
Training and capacity building
Payment for watershed services
Licensing
Investment in water use infrastructure
Off-channel water storage to replace damming
Increased funding
Conclusions and way forward
Chapter 22. Rivers and people
Introduction
Rivers in precolonial Africa
Myths of origin
Socio-cultural
Economic significance of rivers
Politics and conflicts over rivers
Rivers, foreign traders, and colonialists
Rivers and the colonization of Africa
African rivers at the end of colonialism
Rivers in postcolonial Africa
Conflicts over rivers in contemporary Africa
Human and animal interactions in and around Africa's rivers
Riverine cultivation, and environmental laws
Riverscapes and memory in contemporary Africa
Conclusion
Chapter 23. Biodiversity conservation and climate change
Introduction
Overview of key aquatic species in Afrotropical rivers
Multiple stressors in Afrotropical rivers
Land-use intensification
Interbasin water transfers
Overexploitation
Alien and invasive species
Effects of climate change on rivers and streams
Conservation strategies and initiatives for Afrotropical rivers
Protected areas
Restoration projects
Species recovery plans
Environmental education and public campaign
UNEP and World Wildlife Fund
Challenges and opportunities for sustaining healthy populations in Afrotropical rivers
Synthesis and recommendations
Chapter 24. Restoring freshwater ecosystems: Lessons from case studies on riparian vegetation, aquatic weeds and freshwater fish
Introduction
Riparian vegetation
Background and overview
Case study: Acacia mearnsii in riparian environments
Aquatic weeds
Case study: Ecosystem recovery following Salvinia molesta control in the cape fold ecoregion
Lessons learned
Freshwater fish
Case study 1: Successful invasive fish removal from the Rondegat River using the piscicide rotenone, but at what cost?
Case study 2: Unsuccessful mechanical invasive fish removal effort in the Krom River
Case study 3: A successful mechanical nonnative fish removal in the Thee River builds on lessons learned from the Krom River project
Discussion
Conclusions
Chapter 25. Anthropogenic threats
Introduction
Climate change
Climate change–related physical and ecological impacts
Climate change biodiversity-related impacts
Habitat loss and degradation
Invasive species
Invasive parasites
Invasive aquatic weeds
Invasive crustaceans and mollusks
Invasive fish species in African rivers and streams
Invasive herpetofauna in African rivers and streams
Pollution
Domestic waste discharges
Agricultural pollution
Heavy metal pollution and industrial waste discharges
Land conversion and deforestation
Oil spills
Plastic pollution
Emerging pollutants
Overexploitation, overharvesting, and/or overutilization
Other human-induced stressors
Land use and land cover changes
River damming and water extractions
Urbanization, industrialization, and water pollution
Conflicts over water resources
Conclusion
Chapter 26. Woody plant encroachment and impacts on streamflow recharge in arid and semi-arid environments
Introduction
Methods to determine the effects of WPE on streamflow
Shrub–streamflow framework
Water balance method
Direct methods
Sap-flow measurements
Micrometeorological techniques
Soil and water assessment tool (SWAT) model
Hydrus
Regional Hydro-Ecological Simulation System (RHESSys)
Hydrological mechanism in which WPE impacts streamflow
Soil water and surface runoff
Soil infiltrability
Evapotranspiration (ET) of woody plants
Rain canopy interception of woody plants
Groundwater
Influence of WPE on ecohydrological components under different climatic conditions
Streamflow response to woody plant removal
Future studies
Conclusions
Chapter 27. Advances in biomonitoring of streams and rivers
Introduction
Biological assessment and monitoring
Methods used in biomonitoring
Biotic indices
Diversity and richness indices
The multivariate approach
The multimetric approach
Functional approaches
Advances in river biomonitoring in Africa
Bioindicator organisms
Bacteria, viruses and other microbes
Diatoms
Zooplankton
Macrophytes
Macroinvertebrates
Fishes
Birds
Herpetofauna – reptiles and amphibians
Considerations for the development of biomonitoring tools for African rivers
Standardization of sampling and sample processing protocols
Sampling method and gear
Sampling habitat
Sampling conditions
Sample processing
Level of identifications
Classification of river types (typology)
Defining reference conditions
Sensitivity of taxa and metric selection
Use of novel approaches in biomonitoring
Challenges and opportunities in biomonitoring African rivers
Challenges and limitations
Lessons and opportunities
Conclusion and future directions
Chapter 28. Environmental flows
Introduction
River flow regime and its influence on freshwater ecosystems
Alteration of African river flow regimes and ecological responses
Implementation of environmental flows
Legal recognition of environmental flows and embedding in water resources management
Assessment of environmental flows requirements
Management measures to maintain environmental flows in rivers
Accelerating the implementation of environmental flows
Estimate Environmental Flow Needs Everywhere Immediately
Integrate Environmental Flow Management into Every Aspect of Land and Water Management
Establish Institutional Frameworks
Integrate Water Quality Management
Actively Engage All Stakeholders
Implement and Enforce Environmental Flow Standards
Identify and Conserve a Global Network of Free-Flowing Rivers
Build Capacity
Learn by Doing
Conclusion
Chapter 29. Overview and future prospects of African rivers research
Introduction
Emerging frontiers, challenges and opportunities in Afrotropical riverine research
Major river catchments
Biota
Management and conservation
Key research questions in Afrotropical streams and rivers
Major river catchments
Physical structure and ecological processes
African river hydrology and geomorphology
Physicochemical environment
River riparian zones
Organic matter dynamics
Primary production and ecosystem metabolism
Biota
Phytoplankton and microbes
Macrophytes
Woody plant encroachment
Macroinvertebrates
Fishes
Reptiles, birds and mammals
Food webs
Management, conservation and threats
Management, restoration and governance
Anthropogenic threats
Rivers and people
Biodiversity conservation and climate change
Biomonitoring
Environmental flows
Enhancing research capacity
Index

Tatenda Dalu

Dr Tatenda Dalu is a Senior Lecturer in the School of Biology and Environmental Sciences and Leader of the Aquatic Systems Research Group at University of Mpumalanga, Honorary Research Associate at the South African Institute for Aquatic Biodiversity, and a member of the Alien Species Risk Assessment Review Panel of South Africa and British Ecological Society Grants Committee. He is a United Nations Global Environment Outlook 7 Contributing Author, Associate Editor for Aquatic Invasions, African Journal of Ecology, BioInvasions Records, Ecology and Evolution and Frontiers in Water – Environmental Water Quality, and Editorial Board Member for Science of the Total Environment and Environmental Advances. He has Guest Edited for Frontiers in Water and Frontiers in Environmental Science. He is an expert in freshwater riverine, wetland and reservoir ecosystems mainly using phytoplankton, invertebrates, and fish as study organisms. He has previously co-edited two books for Elsevier on Fundamentals of Tropical Freshwater Wetlands: From Ecology to Conservation Management and Emerging Freshwater Pollutants: Analysis, Fate, and Regulation. Working with fellow research colleagues, Dr Dalu has identified and described two new species in South Africa (Copepod Lovenula raynerae) and Zimbabwe (Fairy shrimp Streptocephalus sangoensis).

Affiliations and expertise

School of Biology and Environmental Sciences, University of Mpumalanga, Nelspruit, South Africa

Frank Masese

Dr Frank Masese is a Senior Lecturer in the Department of Fisheries and Aquatic Science at University of Eldoret, Kenya, and an Honorary Research Fellow at the University of Kwa-Zulu Natal, South Africa. He is a Humboldt Postdoctoral Fellow and a Member of the Editorial Boards of Freshwater Biology, International Review of Hydrobiology, PLoS ONE and PeerJ. He has Guest Edited for Hydrobiologia, Frontiers in Water and Frontiers in Environmental Science. His research interests lie mainly in biodiversity assessments, ecosystem ecology and aqueous biogeochemistry, with a focus on riverine ecosystems. His studies straddle the terrestrial-aquatic domain, where he seeks to understand how landscape variables and human activities shape aquatic ecosystem structure and functioning. Working with fellow researchers, Dr Masese is in the final stages of developing a biological criterion for monitoring surface waters in Kenya.

Affiliations and expertise

Department of Fisheries & Aquatic Science, University of Eldoret, Eldoret, Kenya

Life Sciences

Physical Sciences & Engineering

Social Sciences & Humanities

Health