Adaptation, persistence and management of Atlantic salmon in a metapopulation context
In a context of rapid environmental changes and anthropogenic pressures, there is an urgent need to better understand the responses of species and to provide recommendations on how we can manage and conciliate human activities with the functioning of ecosystems. However, there is often a mismatch be...
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| Other Authors: | , , , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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HAL CCSD
2022
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| Subjects: | |
| Online Access: | https://theses.hal.science/tel-04125779 https://theses.hal.science/tel-04125779/document https://theses.hal.science/tel-04125779/file/thesislamarins.pdf |
| Summary: | In a context of rapid environmental changes and anthropogenic pressures, there is an urgent need to better understand the responses of species and to provide recommendations on how we can manage and conciliate human activities with the functioning of ecosystems. However, there is often a mismatch between the scale of species functioning, threats, and management actions. In particular, even if dispersal is a ubiquitous trait in organisms, implications of connectivity and spatial structure for adaptation, persistence, and management of populations are still poorly appreciated for numerous species. This is the case of Atlantic salmon (Salmo salar), for which eco-evolutionary dynamics, exploitation and management of populations are rarely considered within a metapopulation perspective. Yet, growing evidence shows individuals and gene flow among populations of salmon. Motivated by this context, this thesis aims to use an innovative multi-scale approach, from genes to metapopulation, to 1) better understand the capacities of adaptation and persistence of exploited populations of Atlantic salmon and 2) explore management practices that would meet both objectives of conservation and exploitation. Using a spatially explicit demo-genetic agent-based model, I simulated a network of interconnected populations of Atlantic salmon based on the metapopulation of Brittany. Through several scenarios, I explored the influence of a gradient of dispersal rates, various spatial genetic structures, the spatial configuration of populations, and spatial management strategies on the demographic (e.g., stability, persistence) and eco-evolutionary (e.g., life history traits, genetic diversity) dynamics of interconnected and exploited local populations. This thesis highlighted a non-linear relationship between dispersal rates and the stability of the metapopulation, resulting in an optimal portfolio effect for dispersal rates around 20% in a homogeneous network. At local population scale, I demonstrated phenotypic changes induced by ... |
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