Sea-level rise effects on coastal wetlands in Southern California
Oct. 31st, 2017 11AM - 12PM
Eric Stein (presenter), Southern California Coastal Water Research Project
Cheryl Doughty, University of California Los Angeles
Megan Cooper, State Coastal Conservancy
To improve regional predictions of sea-level rise impacts to coastal wetlands, we developed a rule-based model that incorporated topography, sediment accretion rates, tidal inlet dynamics, and plant response into sea-level rise response. The model quantifies wetland habitat conversion driven by sea-level rise by predicting changes in land elevation in relation to sea level (known as hypsometry). This standardized approach can be developed for all wetlands in a region regardless of differing levels of data availability, making it ideal for quantifying regional effects. We applied the model to approximately 100 wetlands along the Southern California coast, representing a broad range of wetland type and data availability. Our findings suggest that if wetlands are confined to their current extents, the region will lose 12% of marsh habitats (vegetated marsh and unvegetated intertidal flats) with 0.6 m of sea-level rise (by 2050) and 48% with 1.6 m of sea-level rise (by 2100). Habitat conversion was more drastic in wetlands with larger proportions of marsh habitats relative to subtidal habitats and occurred more rapidly in small coastal lagoons relative to larger systems. Our assessment can inform management of coastal wetlands by improving our understanding of the drivers relevant to individual wetlands and the significant gaps in data impeding our ability to model response at large scales.