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Abstract Sea level rise is leading to the rapid migration of marshes into coastal forests and other terrestrial ecosystems. Although complex biophysical interactions likely govern these ecosystem transitions, projections of sea level driven land conversion commonly rely on a simplified “threshold elevation” that represents the elevation of the marsh‐upland boundary based on tidal datums alone. To determine the influence of biophysical drivers on threshold elevations, and their implication for land conversion, we examined almost 100,000 high‐resolution marsh‐forest boundary elevation points, determined independently from tidal datums, alongside hydrologic, ecologic, and geomorphic data in the Chesapeake Bay, the largest estuary in the U.S. located along the mid‐Atlantic coast. We find five‐fold variations in threshold elevation across the entire estuary, driven not only by tidal range, but also salinity and slope. However, more than half of the variability is unexplained by these variables, which we attribute largely to uncaptured local factors including groundwater discharge, microtopography, and anthropogenic impacts. In the Chesapeake Bay, observed threshold elevations deviate from predicted elevations used to determine sea level driven land conversion by as much as the amount of projected regional sea level rise by 2050. These results suggest that local drivers strongly mediate coastal ecosystem transitions, and that predictions based on elevation and tidal datums alone may misrepresent future land conversion.
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Data for: Development of a learning community focused on sea-level rise and coastal habitat change
Rapid habitat changes are occuring in salt marshes located in the Northeastern United States, including expansion of ponded areas on the marsh platform, die off of coastal forests, and subsequent colonization of 'ghost forests' by marsh vegetation. This work focuses on two main areas: (1) environmental conditions along the marsh forest border undergoing rapid transitions; and (2) environmental conditions and plant stress in marsh platforms with extensive ponding, with three study sites: in Long Island and Southern New England, where there are often significant slope breaks along the upland (slope ~0.01), and in southern New Jersey on the Atlantic Coastal plan (slope ~0.003). To better understand drivers of environmental change in marsh-forest borders undergoing rapid transitions, we measured shallow groundwater levels, soil salinity, and forest health and structure along the salt marsh-upland border at three sites with varying slopes using installation of shallow groundwater wells, drone imagery and associated image processing, and geophysical methods. To better understand drivers of environmental change on the marsh platform, we measured used piezometers to understand vertical gradients in marsh groundwater levels, and measured photosynthesis and plant biomass and used drone imagery to map plant stress indices, as indicators of plant stress. While we anticipate that this data will be published in journal articles of the next 2 years, we archive collected data to facilitated data sharing, as required by NSF.
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- Award ID(s):
- 1946302
- PAR ID:
- 10494859
- Publisher / Repository:
- Dryad
- Date Published:
- Subject(s) / Keyword(s):
- FOS: Biological sciences Hydrology Salt marsh maritime forest salt water intrusion water table
- Format(s):
- Medium: X Size: 9298011 bytes
- Size(s):
- 9298011 bytes
- Sponsoring Org:
- National Science Foundation
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