Assessing the impact of instream barriers and climate change on wild Atlantic salmon in forested boreal watersheds

Around the world, instream barriers like culverts, weirs and hydropower dams have impacted rivers for decades. Ecosystems previously teaming with migrating fish are now unable to support spawners. Climate change increases the risk, projected to raise river temperatures to unbearable levels, wreaking havoc with more frequent storms and less predictable rainfall. Better approaches to assessing watersheds and the numerous barriers within them is necessary to improve river conditions.This thesis develops a framework approach and toolset to improve the benefits of watershed assessment and restoration decisions.The thesis opens with development of the river restoration planning and analysis (RRPAT) tool. The values-based approach for ecological restoration is a roadmap for improving fish passage-ways, integrating design and decision-making to ensure a results-oriented plan. The case study highlights barrier prioritization on a river in the United Kingdom (UK). RRPAT is complemented by development of the Watershed Fragility Index (WFI) tool, designed to offer a comprehensive evaluation of watershed stressors. The WFI explores spatial analytics and fuzzy logic to tackle complex ecological frameworks, prioritizing stressors to enable superior watershed assessments. The case study covers WFI application on a river in western Newfoundland and Labrador (NL), Canada.Next, the method for assessing climate change impacts at various scale for Atlantic salmon is developed with application of thesis tools. A case study examines 13 popular Atlantic salmon rivers for NL. Additional chapters share the development of the dynamic connectivity assessment tool (D-CAT). The D-CAT can perform complex river network calculations for in-depth barrier analysis, integrating customizable input data with proven connectivity understanding. Case studies covering rivers in both the UK and NL showcase D-CAT effectiveness, providing best barrier restoration choices plus alternatives for improved management decisions.The thesis work closes with policy implications of developed frameworks and tools, including some recommendations for further research considerations.