1st Edition
Ecological Modelling of River-Wetland Systems A Case Study for the Abras de Mantequilla Wetland in Ecuador
Around 6% of the Earth's land surface is covered by wetlands. Wetlands play a key role in hydrological and biogeochemical cycles, delivering multiple benefits to society: sources of water supply, flood regulation, water purification, agriculture, fisheries, and biodiversity. Hence, wetland systems are of immense socio-economic as well as ecological importance. In this research, the focus was on the Abras de Mantequilla (AdM) wetland in the tropical coastal region of Ecuador, a RAMSAR site and case study area for the EU-FP7 WETwin project.
The research in this thesis involves a combination of field data collection, multivariate analysis techniques, as well as numerical modelling studies. The goal was to explore the effects of changes in hydrological forcing on the hydrodynamic and ecohydraulic responses of the wetland. The study aims to contribute to the understanding of how a tropical river-wetland system functions in terms of hydrodynamics, water quality, primary production, and biotic communities. Spatial patterns of biotic communities and environmental variables are obtained as well as spatio-temporal variability of hydrodynamics, water quality, primary productivity and fish habitat-suitability conditions.
In data scarce areas and countries with financial constraints, the combination of field measurements with numerical models was extremely useful and relevant, confirming that these techniques complement each other in obtaining a better understanding of the dynamics of freshwater river–wetland systems. Studies like the present research can be used to enhance awareness about the environmental services of wetlands and stimulate cooperation between all stakeholders in order to achieve more sustainable wetland management.
1 INTRODUCTION
1.1 THE ROLE OF WETLANDS
1.2 WETLAND CONSERVATION
1.3 ECOSYSTEM SERVICES
1.4 WETLAND DYNAMICS, STRUCTURE AND FUNCTION
1.5 THE WETWIN PROJECT
1.6 THE ABRAS DE MANTEQUILLA WETLAND IN ECUADOR
1.7 CAPABILITIES OF MATHEMATICAL MODELLING TOOLS
1.8 OVERALL RESEARCH APPROACH
1.9 SPECIFIC RESEARCH QUESTIONS
1.10 THESIS OUTLINE
2 HYDRODYNAMICS OF THE TROPICAL ADM RIVER-WETLAND SYSTEM
2.1 GEOGRAPHICAL CONDITIONS
2.2 HYDROLOGICAL AND METEOROLOGICAL CONDITIONS
2.3 THE ADM RIVER-WETLAND SYSTEM
2.4 NATURAL VARIABILITY IN HYDRODYNAMIC CONDITIONS
2.5 WATER BALANCE AND RELATIVE CONTRIBUTIONS OF INFLOWS
2.6 CONDITIONS DURING MEASUREMENT CAMPAIGNS 2011&2012
2.7 DISCUSSION
3 ENVIRONMENTAL VARIABLES AND SPATIAL PATTERNS
3.1 BACKGROUND
3.2 FIELD MEASUREMENT CAMPAIGNS
3.3 SAMPLING RESULTS WITHIN THE WATER BODY
3.4 SAMPLING RESULTS OF BOTTOM SEDIMENT
3.5 CONCENTRATIONS, GRADIENTS AND KEY VARIABLES
4 COMMUNITY STRUCTURE OF BIOTIC ASSEMBLAGES
4.1 BACKGROUND
4.2 FIELD MEASUREMENT CAMPAIGNS
4.3 PHYTOPLANKTON
4.4 ZOOPLANKTON
4.5 MACROINVERTEBRATES
4.6 FISH
4.7 SUMMARY OF SIMILARITIES
4.8 SUMMARY OF DISSIMILARITIES
4.9 LINKING BIOTIC ASSEMBLAGES WITH ENVIRONMENTAL VARIABLES
4.10 DISCUSSIONS
5 EVALUATION OF WATER QUALITY AND PRIMARY PRODUCTION DYNAMICS
5.1 BACKGROUND AND SCOPE
5.2 MODEL SET UP
5.3 MODEL PERFORMANCE AND VERIFICATION
5.4 SCENARIOS
5.5 DISCUSSION
6 EVALUATION OF HABITAT SUITABILITY CONDITIONS FOR FISH
6.1 BACKGROUND AND SCOPE
6.2 STUDY AREA
6.3 THE HABITAT SUITABILITY INDEX
6.4 RESULTS
6.5 DISCUSSION
7 DISCUSSION AND SYNTHESIS
7.1 SUSTAINABILITY OF THE ADM WETLAND HYDRODYNAMICS
7.2 MASS BALANCES OF NUTRIENTS
7.3 MASS BALANCES OF PRIMARY PRODUCERS
7.4 NUTRIENT BALANCES AND THEIR VARIATIONS BETWEEN DIFFERENT HYDROLOGICAL CONDITIONS
7.5 WETLAND PRODUCTIVITY AND RELATED PROCESSES
8 CONCLUSIONS AND RECOMMENDATIONS
8.1 RESEARCH APPROACH
8.2 SPATIO-TEMPORAL VARIABILITY OF THE ADM WETLAND HYDRODYNAMICS
8.3 DOMINANT AND KEY SPECIES IN THE ADM WETLAND SYSTEM
8.4 SPATIAL PATTERNS IN THE DISTRIBUTION OF THE ENVIRONMENTAL VARIABLES AND BIOTIC COMMUNITIES
8.5 MAIN PHYSICO-CHEMICAL AND ECOLOGICAL PROCESSES
8.6 SPATIO-TEMPORAL VARIABILITY OF FISH-HABITAT SUITABILITY
8.7 MANAGEMENT MEASURES FOR THE ADM WETLAND
8.8 NUMERICAL MODELLING AS A TOOL TO DESCRIBE WETLAND DYNAMICS
8.9 RECOMMENDATIONS FOR FURTHER RESEARCH
REFERENCES
APPENDIX A
A.1 THE 1 D DE SAINT-VENANT EQUATIONS
A.2 THE 2D DE SAINT-VENANT EQUATION
APPENDIX B
B.1 THE 1D ADVECTION-DISPERSION EQUATION
B.2 THE 2D ADVECTION-DISPERSION EQUATION
APPENDIX C
APPENDIX D
APPENDIX E
Biography
Maria Gabriela Alvarez Mieles was born in Guayaquil, Ecuador. She has a Bachelor degree in Biology from the Natural Sciences Faculty at Universidad de Guayaquil, with honours 'Accesit al Contenta' equivalent to magna cum laude. During her early career, she has worked at the Aquatic Pollution department of a National Research Institute in Ecuador (Instituto Nacional de Pesca - INP), participating in monitoring campaigns in some of the main rivers, sea, and estuaries in protected areas. Later she joined Efficacitas, an environmental consultancy office where she participated in several environmental impact assessments, audits and monitoring campaigns for different productive sectors of Ecuador (water, electric, hydrocarbons, mining and industry).
She pursued the MSc in Environmental Sciences at UNESCO-IHE, specialization Planning and Management, with a fellowship from the World Bank (2007). Her MSc thesis was about "Ecological Indicators-A tool for assessment the present state of a river. A pre-impoundment study in Quevedo-River, Ecuador". IN 2007, she received an internship at DELTARES, in the Marine and Coastal Department for one of the R&D projects on 'Building with Nature'. In 2008, she was engaged at UNESCO-IHE, first contributing to the EU funded research project based on Lake Maryut (Egypt). In 2009, she had the opportunity to join the WETwin project (EU funded), as a researcher for the Ecuadorian case study (on a wetland in the Guayas River Basin). The project focus aimed to enhance the role of wetlands in integrated water resource management. Her involvement in this project motivated her to pursue a PhD in order to enhance the research for the Abras de Mantequilla wetland.
She developed her PhD research at UNESCO-IHE, Department of Water Sciences & Engineering, with a fellowship from the Dutch Ministry of Foreign affairs (Netherland fellowship programme NFP-NUFFIC), and financial support from the WETwin project for her fieldwork campaigns. Her PhD thesis was on environmental monitoring and modelling of the ‘Abras de Mantequilla’ wetland (RAMSAR site 2000) in Ecuador, applying analytical metrics and ecological modelling to enhance the understanding of tropical wetland systems.
