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Accueil du site → Doctorat → Canada → Vulnerability and adaptability of Africa’s inland fisheries to climate change : an interdisciplinary approach to a multi-dimensional conservation challenge

McGill University, Montreal (2018)

Vulnerability and adaptability of Africa’s inland fisheries to climate change : an interdisciplinary approach to a multi-dimensional conservation challenge

Nyboer, Elizabeth A.

Titre : Vulnerability and adaptability of Africa’s inland fisheries to climate change : an interdisciplinary approach to a multi-dimensional conservation challenge

Auteur : Nyboer, Elizabeth A.

Université de soutenance : McGill University, Montreal

Grade : Doctor of Philosophy 2018

Résumé
The unprecedented rate of contemporary climate warming is affecting ecosystems globally ; and inland waters are predicted to be among the most vulnerable as they are already heavily exploited by humans for numerous ecosystem services. My doctoral research examined the effects of climate change on the inland fisheries of continental Africa, with a special focus on the ecological and social consequences for the Lake Victoria basin of East Africa. First, I used a trait-based climate-change vulnerability assessment (CCVA) of African freshwater fishes to document biogeographical patterns of climate change threats across the continent. By integrating species traits with projected climatic changes, I identified regions and species that are most at risk, and demonstrated that nearly 40% of African freshwater fish species are highly vulnerable to climate change. This study was also important in highlighting several cases where classic conservation approaches have overlooked species and regions of climate change concern. In the remainder of this dissertation, I focused on the Lake Victoria basin of East Africa, a region that emerged as highly threatened in the CCVA. In a suite of short- and long term acclimation experiments, I tested the capacity of a commercially harvested species (the Nile perch, Lates niloticus), to cope with climate change stresses through physiological adjustments of their thermal tolerance limits. I acclimated Nile perch to a wide range of temperatures over various exposure times (3-days, 3-weeks, 3-months), and measured changes to upper thermal tolerance, metabolic performance, growth, and organ development among temperatures and acclimation times. I found that Nile perch showed evidence for compensation in upper thermal tolerance and metabolic rate over all exposure times, and demonstrated that temperature-induced cardiac remodelling influenced aerobic function in this species. The key findings of this work challenge long-held assumptions that tropical species have limited thermal plasticity for coping with climate change-related stressors. Finally, I investigated vulnerability and resilience of fishery-based social-ecological systems in the Lake Victoria basin. Household surveys, focus group discussions, and key informant interviews were conducted in five villages ranging from low to high-dependence of fishing to determine how households and communities are affected by and respond to climate-mediated changes in the fishery. I found that climate change is highly disruptive to fishery-based livelihoods, causing social-ecological feedbacks that tend to entrench households and communities into a singular dependence on an already threatened and declining resource. However, fishers’ growing awareness of these interactions can lead to adaptive actions that improve resilience to the ongoing changes in this ecosystem. Overall this thesis provides critical insight into climate change vulnerability of Africa’s inland aquatic environments, and highlights several mechanisms that may underlie resilience in fish species and the human communities that rely on them.

Présentation (CRDI)

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