Forecasting ecosystem services to guide coastal wetland rehabilitation decisions

Abstract Coastal wetlands provide diverse ecosystem servicessuch as flood protection and recreational value. However, predicting changes in ecosystem servicevalue fr0k from restoration or management is challenging because environmental systems are highly complex and uncertain. Furthermore, benefits are diverse and accrue over various timescales. We developed a generalizable mathematical coastal managementmodel to compare restoration expenditures to ecosystem servicebenefits and apply it to McInnis Marsh, Marin County, California, USA. We find that benefits of restoration outweigh costs for a wide range of assumptions. For instance, costs of restoration range from 8–30% of the increase in ecosystem servicevalue over 50 years depending on discount rate. Flood protection is the dominant monetizedservice for most payback periodsand discount rates, but other services (e.g., recreation) dominate on shorter timescales (>50% of total value for payback periods≤4 years). We find that the range of total ecosystem servicevalue is narrower than overall variability reported in the literature, supporting the use of mechanistic methods in decision-making around coastal resiliency. However, the magnitude and relative importance of ecosystem servicesare sensitive to payback period, discount rate and risk tolerance, demonstrating the importance of probabilistic decision analysis. This work provides a modular, transferrable tool to that can also inform coastal resiliency investments elsewhere.