Enhancing BC Estuaries

Sustaining Fish and Fish Habitat in a Changing Climate

Estuaries and coastal wetlands comprise less than 3% of BC’s coastline, yet they support over 80% of BC’s coastal fish and wildlife, and provide critical habitat for Pacific salmon. Climate change is expected to significantly impact estuary ecosystems through a number of mechanisms, including rising sea-levels, ocean acidification, temperature and salinity changes, changes to freshwater and sediment inputs.

Study Overview

The Nature Trust of British Columbia has secured funding from the BC Salmon Restoration and Innovation Fund to implement a five-year project to improve estuary habitat to enhance the long-term sustainability and health of wild BC fish stocks. We will be working with Coastal First Nations and our partners in the West Coast Conservation Land Management Program. Funding for this project is provided under the BC Salmon Restoration and Innovation Fund, a contribution program funded jointly between Fisheries and Oceans Canada, and the Province of BC.

The U.S. National Estuarine Research Reserve System developed the Marsh Resilience to Sea-Level Rise (MARS) tool – a powerful approach to evaluate and compare the ability of tidal marshes to persist and thrive as sea levels rise. They conducted their research in estuaries along the west coast of the United States. The Nature Trust of BC’s research program will extend the coverage of that research northwards along the west coast of North America, providing a Canadian context.

The project takes a two-pronged approach:

• Conducting monitoring and research to assess estuary resilience to sea-level rise at 15 sites on Vancouver Island, the central coast and Haida Gwaii.
• Implementation of several major ecological restoration projects to restore core estuarine processes in Years 4 and 5.

Informed Decision-Making

This project will increase the knowledge and capacity of all partners to make informed management, conservation, restoration, and enhancement decisions in these important coastal ecosystems in the face of climate change and sea-level rise.

Assessing Estuary Resilience to Sea-Level Rise

At each site, The Nature Trust and Coastal First Nations will use a variety of equipment to collect data and implement the MARS tool. Data will be collected for five categories of resilience during the study: distribution of marsh elevation, change in elevation, sediment supply, tidal range, and rate of sea-level rise. Within each category, metrics will be given a score of 1 to 5, indicating level of resilience from low to high. These will be used to calculate an overall score indicating the level of resilience to sea-level rise for each site.

Asseek Estuary conservation area

Implementation of Ecological Restoration Projects

The output of the MARS scoring will provide baseline information to inform the ecological restoration phase of the project. Identification and subsequent feasibility studies of candidate restoration projects will be undertaken in Years 2 and 3 of the project. In Years 4 and 5, The Nature Trust will deliver two transformational projects that restore core natural estuarine processes (including the collection of pre- and post-restoration monitoring metrics).

Examples of restoration activities The Nature Trust and our partners have previously implemented include removal of historical agricultural dykes/berms, and construction/reconnection of tidal channels, aimed at restoring estuarine hydrology and improving tidal connectivity which benefits fish, wildlife, plants and other coastal species.