Presenter/s: Emily Howe, PhD
Symposium Session: 2024 - 02 Restoring Puget Sound Estuaries: Insights from Monitoring and Lessons Learned from Construction
Topics covered: estuary and fish-salmon
ABSTRACT
Connected and resilient landscapes are beneficial for Chinook salmon recovery, yet we lack a framework for assessing the potential effectiveness of estuarine restoration designs over broad temporal and spatial scales. As a result, it is difficult to accurately assess the return-on-investment tradeoffs when comparing alternative designs. To address this issue, we developed an analytical framework using hydraulic, landscape connectivity-abundance, and bioenergetic models to compare the abundance and growth potential of juvenile Chinook salmon across a suite of restoration and climate scenarios. The framework stems from two hypotheses: H1) Well placed restoration projects support increased juvenile Chinook salmon use beyond the intended project area by increasing connectivity among sites or by creating or promoting areas with high growth potential; and H2) Warming water temperatures driven by climate change counteract restoration efforts by increasing the metabolic demand of juvenile Chinook salmon feeding in estuarine deltas, which may be further impacted by poor project placement. To develop the comparative framework, we leveraged restoration design plans and monitoring data for projects in the Stillaguamish delta in Washington State, where over 900 acres of estuarine wetlands are on track for restoration through a series of past, current, and future restoration projects. We used design plans, abundance estimates, and growth potential results to evaluate which juvenile Chinook salmon recovery actions provide cumulative, broad-scale restoration benefits and remain resilient to future climate change. This work thus examines the extent to which salmon recovery planning requires looking beyond project boundaries to include consideration of project placement within the estuarine landscape mosaic.