Impact of environmental changes on life history, demography and population dynamics in salmonids

• Main Author: Montorio, Lucie
• Other Authors: Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Agrocampus Ouest, Guillaume Evanno
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2017
• Subjects: Partial migration; Salmo; Resilience; Life history tactic; Demographic parameters; Population model; Migration partielle; Résilience; Tactique d’histoire de vie; Paramètre démographique; Modèle de population; [SDV.EE]Life Sciences [q-bio]/Ecology; environment; Atlantic salmon; Salmo salar
• Online Access: https://theses.hal.science/tel-01886982; https://theses.hal.science/tel-01886982/document; https://theses.hal.science/tel-01886982/file/pdf2star-1538568502-VF-avec-couv.pdf

This thesis investigates the influence of the tactic diversity on population dynamics in two partially migratory salmonids: Atlantic salmon, Salmo salar and brown trout, Salmo trutta. These two species have high ecological and economic values but the role of migrant and resident individuals on population dynamics and resilience to environmental changes is currently largely unknown. I undertook a multidisciplinary approach combining demographic, genetic, and modeling tools to address these issues in populations from France. I found that tactic determination is partly plastic as juveniles can respond to environmental variations by migrating. In addition, this thesis showed that tactics diversity in partially migratory populations enables a better use of favorable environmental conditions and buffer the effects of unfavorable conditions on their dynamics.These two processes might promote a higher resilience of partially migratory populations to environmental change, including anthropogenic effects, than in solely migratory or resident populations. Nonetheless, given the different strategies in Atlantic salmon and brown trout, my results suggested that brown trout should have better abilities to response to environmental changes and a higher level of resilience than Atlantic salmon. Cette thèse étudie l’influence de la diversité des tactiques d’histoire de vie sur la dynamique des populations de deux salmonidés à migration partielle: le saumon Atlantique, Salmo salar et la truite commune, Salmo trutta. Ces deux espèces ont de fortes valeurs écologique et économique, mais les rôles respectifs des individus résidents et migrateurs sur la dynamique et la résilience des populations à des changements environnementaux demeurent méconnus. Nous avons abordé ces questions par des approches démographiques, génétiques et de modélisation. Nous avons démontré que la détermination de la tactique d’histoire de vie est en partie plastique et permet aux individus juvéniles de migrer en réponse à un changement de l’environnement. ...