The characteristics of some coastal wetlands make them more likely to adapt to sea level rise (SLR) and remain diverse and productive even as they adjust to climate-induced changes. In this project, we mapped these characteristics and estimated the relative resilience of over 1,800 coastal sites across the Arctic, Beringian, and Pacific regions of Alaska based on their capacity to sustain biodiversity and natural services under four SLR scenarios. Each site received a resilience “score” based on the likelihood that its coastal habitats can and will migrate to adjacent lowlands. The products of this study include: 

  • A report describing the methods used to evaluate sites and the results for each coastal shoreline region in the Arctic, Beringian, and Pacific regions of Alaska
  • A web tool allowing users to view and interact with the results for any coastal site
  • Downloadable datasets including results for additional sea level rise scenarios 

Alaska Findings:  
The results of this study highlight the need for different conservation and management strategies for tidal marsh in Alaska’s three regions. Alaska’s Arctic region appears to have the most potential for marshes to migrate in response to increasing sea levels up to two meters, though marshes in this region area also more vulnerable to coastal erosion. Ensuring that migration space areas remain intact and protected from development and natural resource extraction will provide opportunities for tidal marsh to move into these adjacent low-lying lands. Lower-elevation salt marshes in the Beringian region also have some potential to migrate, but many Beringian tidal marshes occur at elevations greater than two meters, suggesting they will be resilient to any sea level increases reasonably expected to occur by 2100 along Alaska’s coast. As in the Arctic, these marshes will likely be susceptible to the impacts of coastal storms as the protective buffer of sea ice continues to decline. Based on our inundation modeling, Alaska’s Pacific or Southeast region has very little migration space for its existing marshes, even before incorporating projected future uplift from glacier retreat. In the short-term, Pacific tidal marshes are likely most threatened by human development as they occur in low-lying areas that are most suitable for human development in the rocky and topographically diverse lands of Southeastern Alaska (Boggs et al. 2019). The long-term impacts to these tidal marshes will depend largely on local uplift rates, with some marshes likely transitioning into non-tidal habitats.  

Partners: Technical methods for mapping and estimating coastal site resilience were developed through previous projects in the Northeast and Mid-Atlantic, Gulf of Mexico, and South Atlantic US coasts in concert with a steering committee of experts for each project that included representatives from the U.S. Fish and Wildlife Service (USFWS), National Oceanic and Atmospheric Association (NOAA), and U.S. Geological Survey (USGS), as well as agency and academic staff from the three respective project areas. We modified and adjusted these methods as needed for Alaska with the help and review of a steering committee that met every other month for a year to discuss data, concepts and methods, and to review results. Our methods are described fully in the final report.

Funding: This research was funded by grants from the Doris Duke Charitable Foundation.

Boggs, K., L. Flagstad, T. Boucher, M. Carlson, A. Steer, B. Bernard, M. Aisu, P. Lema, B. Heitz, and T. Kuo. 2019. Alaska Ecosystems of Conservation Concern: Biophysical Settings and Plant Associations. Report prepared by the Alaska Center for Conservation Science, University of Alaska, Anchorage for the Alaska Department of Fish and Game. 300 pp.

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