Evaluating the Vulnerability of Freshwater Habitats

Vulnerability and adaptation of freshwater ecosystems to climate change in the Cariboo-Chilcotin, British Columbia

Fraser Salmon and Watersheds Program, BC Ministry of Environment, and Pacific Fisheries Resource Conservation Council

Across British Columbia, climate change is expected to have adverse effects on stream flow and water temperatures which can translate to impacts on freshwater ecosystems and fish communities. Credible information about vulnerability and adaptation is critical so organizations know where to act, when to act, and how significantly to act so as to avoid wasting precious time, money, and human resources.

Through this work ESSA assessed the vulnerability of freshwater ecosystems to climate change from the perspective of bull trout, coho salmon, and Chinook salmon habitats in the Cariboo-Chilcotin of BC. In particular, ESSA used statistically downscaled climate projections as inputs into a physically-based macro-scale hydrologic model and an empirical stream temperature model to predict flow conditions and water temperatures for hundreds of watersheds across the study area. Stream flow and temperature projections were then compared against biologically-based criteria to determine the accessibility and suitability of freshwater habitats for a historic reference and three future time periods. Results showed that there would be both some gains and loses as a result of climate change in the region which varied by fish species. Adaptation opportunities were identified by linking these results to existing land and water uses.

This project was successful at demonstrating a novel approach for assessing vulnerability and identifying adaptation strategies. In particular, this study demonstrated how a vulnerability assessment was useful for understanding the relative vulnerabilities of different fish species, identifying priorities for the protection of freshwater habitats, and understanding overlaps between vulnerabilities and opportunities for adaptation in natural resource decision making

This work has been profiled at the following conferences:

Project reports for the Cariboo-Chilcotin assessment and the follow up Central Interior study can be accessed from the Think Salmon website.