Challenges and opportunities for aquatic ecosystem management with uncertain global change
Cline, Timothy Joseph
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Society is faced with the task of effectively managing to enable ecosystem resilience to anthropogenic stressors and future change. Ecosystems are part of complex social-ecological systems where humans impact ecosystems and anthropogenic change and natural variability feed back to impact people. Management of ecosystems also involves balancing different ecosystem services and values that people place on ecosystems. These complex challenges for the management of social-ecological systems require interdisciplinary approaches that address these challenges from multiple scales. In this dissertation, I examine patterns and processes in ecosystems and social-ecological systems that may provide opportunities for management to overcome some of the challenges for the future. In chapter one, I assess how multiple stressors impact the life cycle of a commercially important fish species and demonstrate that multiple stressors impact important life-history complexity with implications for population stability. These changes may make populations less reliable for commercial fisheries. In the second chapter, I evaluate the interaction between two competing ecosystem services and show that common ecological processes including density-dependence and population stochasticity reduce the strength of the interaction between them and render multiple benefits from ecosystems with a relatively simple management strategy. In my third chapter, I examine how population density and stream habitat characteristics interact to influence the habitat usage of sockeye salmon on the spawning grounds, which can alter their ecological benefit to freshwater ecosystems and the effectiveness of habitat restoration. In my final chapter, I explore how human communities can exploit complexity in the natural environment to buffer against uncertainty and catastrophic shifts in social-ecological systems. This work takes an interdisciplinary approach to addressing these challenges for management. The research spans multiple scales from species to ecosystems and incorporates humans in complex social-ecological systems. Management of ecosystems is challenging due to the immense amount of complexity. However, complexity in nature can provide stability and opportunities for management to take advantage of to improve management outcomes given uncertain global change.
- Fisheries