East Africa’s Lake Victoria provides resources and services to millions of people on the lake’s shores and abroad. In particular, the lake’s fisheries are an important source of protein, employment, and international economic connections for the whole region. Nonetheless, stock dynamics are poorly understood and currently unpredictable. Furthermore, fishery dynamics are intricately connected to other supporting services of the lake as well as to lakeshore societies and economies.
Much research has been carried out piecemeal on different aspects of Lake Victoria’s system; e.g., societies, biodiversity, fisheries, and eutrophication. However, to disentangle drivers and dynamics of change in this complex system, we need to put these pieces together and analyze the system as a whole. We did so by first building a qualitative model of the lake’s social-ecological system. We then investigated the model system through a qualitative loop analysis, and finally examined effects of changes on the system state and structure. The model and its contextual analysis allowed us to investigate system-wide chain reactions resulting from disturbances. Importantly, we built a tool that can be used to analyze the cascading effects of management options and establish the requirements for their success.
We found that high connectedness of the system at the exploitation level, through fisheries having multiple target stocks, can increase the stocks’ vulnerability to exploitation but reduce society’s vulnerability to variability in individual stocks. We describe how there are multiple pathways to any change in the system, which makes it difficult to identify the root cause of changes but also broadens the management toolkit. Also, we illustrate how nutrient enrichment is not a self-regulating process, and that explicit management is necessary to halt or reverse eutrophication. This model is simple and usable to assess system-wide effects of management policies, and can serve as a paving stone for future quantitative analyses of system dynamics at local scales.
General news | 2017-12-12
See video from eminar with Professor Rashid Sumaila, one of the world’s most innovative researchers on the future of the oceans
Research news | 2017-11-30
The PECS-II conference showcased place-based research and how it can help us work towards global sustainability in the Anthropocene
Research news | 2017-11-28
How urban greening and civic ecology projects can improve human well-being and restore crucial ecosystem services
Research news | 2017-11-27
What plantain farmers in Costa Rica can teach us about the inconsistent links between access to ecosystem services and well-being
Research news | 2017-11-23
Centre science director well established among world’s most top-cited and influential scientists
Research news | 2017-11-21
Large-scale changes in Arctic marine food web can be expected within 50 years, some good, but in the long run several critical