Foundations of modeling resilience of tidal saline wetlands to sea-level rise along the U.S. Pacific Coast

Abstract

Context Tidal saline wetlands (TSWs) are highly threatened from climate-change effects of sea-level rise. Studies of TSWs along the East Coast U.S. and elsewhere suggest significant likely losses over coming decades but needed are analytic tools gauged to Pacific Coast U.S. wetlands. Objectives We predict the impacts of sea-level rise (SLR) on the elevation capital (vertical) and migration potential (lateral) resilience of TSWs along the Pacific Coast U.S. over the period 2020 to 2150 under a 1.5-m SLR scenario, and identified TSWs at risk of most rapid loss of resilience. Here, we define vertical resilience as the amount of elevation capital and lateral resilience as the amount of TSW displacement area relative to existing area. Methods We used Bayesian network (BN) modeling to predict changes in resilience of TSWs as probabilities which can be useful in risk analysis and risk management. We developed the model using a database sample of 26 TSWs with 147 sediment core samples, among 16 estuary drainage areas along coastal California, Oregon, and Washington. Results We found that all TSW sites would lose at least 50% of their elevation capital resilience by 2060 to just before 2100, and 100% by 2070 to 2130, depending on the site. Under a 1.5-m sea-level rise scenario, nearly all sites in California will lose most or all of their lateral migration resilience. Resilience losses generally accelerated over time. In the BN model, elevation capital resilience is most sensitive to elevation capital at time t, mean tide level at time t, and change in sea level from time 0 to time t. Conclusions All TSW sites were projected with declines in resilience. Our model can further aid decision-making such as prioritizing sites for potential management adaptation strategies. We also identified variables most influencing resilience predictions and thus those potentially prioritized for monitoring or development of strategies to prevent loss regionally.

Impacts of Freshwater Sources on Salinity Structure in a Large, Shallow Estuary

“…Accelerating sea-level rise (SLR), shifting precipitation patterns, and frequency and intensity of storms will affect coastal ecosystems, including salt marshes. Similar to these studies referenced [23,24], SLR is a major future contributor to material distributions (i.e., salinity and nutrients) within Florida Bay. For example, "shallow mud-banks" near the coastline, where bathymetry is not well defined, will be covered at a minimum with 90 cm of rising saltwater by the end of this century [1].…”

“…Unlike their approach, we focused primarily on freshwater inflow as planned and executed through several CERP projects [5], mainly due to the complexity and highly managed systems of canals, wetlands, pumps, and reservoirs, upstream of the Everglades National Park. Furthermore, hydrodynamic and other model-types have demonstrated the need for applying such tools to predict future impacts from SLR on wetlands along the west coast of the USA [24]. In the study referenced, they used a different modeling approach using Bayesian network (BN) to predict changes in resilience of tidal saline wetlands as probabilities, which can be useful in risk analysis [24].…”

“…Furthermore, hydrodynamic and other model-types have demonstrated the need for applying such tools to predict future impacts from SLR on wetlands along the west coast of the USA [24]. In the study referenced, they used a different modeling approach using Bayesian network (BN) to predict changes in resilience of tidal saline wetlands as probabilities, which can be useful in risk analysis [24].…”