Mapping riparian morphology change for critical habitat conservation and watershed management planning

Description: This applied research project aims to evaluate climate change impacts relating to watershed degradation of salmon habitats with a focus on the culturally significant endangered inner Bay of Fundy (iBoF) Atlantic salmon in the Cobequid Bay, Nova Scotia. The research has practical importance for quantifying, mapping, and assessing changes of physical salmon habitat conditions in the last decade and can point to climate-resilient properties of analyzed riparian zones, estuaries, and prioritize cold-water refuge restoration sites for watershed management planning. With funding from FCAS, Dr. Dawson intends to generate LiDAR derived spatial maps of temporal morphology and riparian changes, a watershed assessment, and publication in a peer-reviewed journal to suggest riverscape restoration conditions for nature-based solutions. The funding is also in support of a larger watershed assessment project entitled “Restoration through Overhead Refugia Exploration – ResTORE” developed by the Maritime Aboriginal Peoples Council (MAPC). Previous watershed projects completed by the MAPC found limited data on the existence of cold-water refuges in these watersheds and eDNA research found iBoF salmon populations are present, which highlights the immediate need to ensure access to cold-water refuges (project watershed maps attached).

Aerial survey data collection, statistical analysis, and spatial mapping of Atlantic salmon habitat conditions will provide valuable information for identifying priorities of conservation, restoration strategies, and watershed management planning more broadly. The project will use LiDAR surveying equipment and data processing facilities. Surveys will collect topographic and vegetation data of priority locations within the watersheds and sites will be selected based on the ResTORE project aims. Applied research will focus on river and estuarine morphology and riparian forest change analysis by comparing newly collected LiDAR data (2024) and high-resolution LiDAR derived data collected in the years 2013 and 2019 by the Province of Nova Scotia. These temporal comparisons will determine how critical iBoF salmon habitats have adjusted to physical watershed changes and identify aspects of critical habitats which have remained resilient to high-magnitude storm events.

The quantification of riparian forest degradation between 2019 and 2024 will be of particular interest for evaluating recent climate change impacts such as Hurricane Fiona (2022) and a historic rainstorm event in 2023. While climate related economic damage and flood risk mapping are being studied in urbanized areas, ecological impacts on Atlantic salmon habitats in rural landscapes are required for improving watershed management planning efforts. Quantified physical properties (topography and vegetation) will serve as a basis understanding the impacts of watershed changes on cold-water refuge areas and planning for climate change adaptation strategies for iBoF salmon conservation and restoration. Analytical methods will specifically investigate riparian changes including aspect (slope direction), volumetric properties of erosion and deposition, and riparian forest canopy height, density, and shade characteristics. Identifying further riparian conditions which remained resilient to these high-magnitude adjustments will point to restoration solutions most suitable for long-term iBoF salmon conservation success and provide valuable information for broad applications outside the scope of this study. Findings will offer transferability to other groups and jurisdictions by, in part, providing new high-resolution surface data and analytical riparian habitat condition maps. In collaboration with the MAPC, results of this study can provide opportunities for additional research objectives including identifying industrial runoff impacts on water quality, delineation of salt marshes, and recognizing invasive species impacts for future projects.