|Modeling Wetland Response to Sea-Level Rise on the Pacific Coast
To gather reliable estimates of climate change impacts at regional scales, scientists at WERC and partners are using local physical and biological data to assess change to nearshore ecosystems. WERC members and University partners have collected information from 18 coastal wetland sites in Washington, Oregon, and California. Our study is focused on collecting high-quality data at local site scales, and then using that data to provide information that may be interpreted across the entire latitudinal gradient of the Pacific Coast.
In addition to our extensive network of sites, three estuaries in California have been intensely surveyed and metered to represent Mediterranean and northern Oceanic climate regimes (San Diego, San Francisco Bay, and Humboldt Bay respectively). At all sites we examine potential climate change effects and vulnerability of nearshore habitats and their dependent wildlife. Using local habitat information, we develop approaches for investigating the complexity of climate-induced physical and biological changes to wetland ecosystems, both at scales relevant to land managers, as well as a broader Pacific coast perspective.
Map of CERCC sites along the Pacific Coast divided into northern and southern regions.
Conceptual model of elevation, tidal range, vegetation, and wildlife over the continuum of nearshore habitat.
1. Downscale physical processes and climate projections to local scales
We are using climate models, such as the Weather Research and Forecasting Model (WRF) and the Coastal Storm Modeling System (CoSMoS), to assess impacts to tidal marsh and nearshore ecosystems at local scales and to provide information for future wave impacts and inundation (including frequency and depth of inundation) under a range of sea-level rise and storm scenarios.
2. Measure morphological and ecological characteristics across the habitat continuum of tidal marsh, intertidal mud flat, and subtidal shoals
We use a variety of survey methods to capture marsh and nearshore characteristics which will then be used to model impacts from different sea-level rise and storm scenarios.
Information collected includes:
- Fine-scale marsh elevation using a Real Time Kinematic GPS (RTK GPS)
- Plant composition and diversity
- Bird abundance and habitat use
- Bathymetric surveys to map mud flats and shallow subtidal zones
- Bed sediment flux (suspended sediment concentrations)
- Water level, salinity, and temperatures
- Weather characteristics
- Marsh sediment cores to measure accretion rates and stability
- Surface Elevation Tables (SETs) to measure marsh elevation changes
3. Model wildlife habitats and native species response
We are correlating vegetation data with elevation, inundation patters, soil salinity, and spatial location to model habitat and vegetation change in relation to climate change and sea-level rise. We are also creating endangered species distribution models to forecast wildlife species losses with sea-level rise scenarios in California estuaries.
4. Examine spatial variability of sea-level rise vulnerability along a coastal latitudinal gradient
Results from modeling are synthesized to examine variation in ecological response to climate change at different latitudes and tidal ranges along the Pacific coast.
We determine relative risk of nearshore habitats to climate change and sea-level rise, and have identified areas of specific concern.