Nonlinear Patterns of Surface Elevation Change in Coastal Wetlands: the Value of Generalized Additive Models for Quantifying Rates of Change

Laura C. Feher, Michael J. Osland, Darren J. Johnson, James B. Grace, Glenn R. Guntenspergen, David R. Stewart, Carlos Coronado-Molina, Fred H. Sklar

Research output: Contribution to journalArticlepeer-review


In the face of accelerating climate change and rising sea levels, quantifying surface elevation change dynamics in coastal wetlands can help to develop a more complete understanding of the implications of sea-level rise on coastal wetland stability. The surface elevation table-marker horizon (SET-MH) approach has been widely used to quantify and characterize surface elevation change dynamics in coastal marshes and mangrove forests. Whereas past studies that utilized the SET-MH approach have most often quantified rates of surface elevation change using simple linear regression analyses, several recent studies have shown that elevation patterns can include a diverse combination of linear and non-linear patterns. Generalized additive models (GAMs) are an extension of generalized linear models (GLMs) that have previously been used to analyze a variety of complex ecological processes such as cyclical changes in water quality, species distributions, long-term patterns in wetland area change, and palaeoecological time series. Here, we use long-term SET data to demonstrate the value of generalized additive models for analyzing non-linear patterns of surface elevation change in coastal wetlands. Additionally, we illustrate how the GAM approach can be used to effectively quantify rates of elevation change at both landscape- and local site-level scales.

Original languageEnglish (US)
JournalEstuaries and Coasts
StateAccepted/In press - 2023

Bibliographical note

Funding Information:
This research was supported by the U.S. Geological Survey (USGS) Greater Everglades Priority Ecosystems Science Program, the USGS Ecosystems Mission Area, and the USGS Climate R&D Program. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Publisher Copyright:
© 2023, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.


  • Coastal wetlands
  • Generalized additive models
  • Marker horizon
  • SET-MH
  • Sea-level rise
  • Surface elevation change
  • Surface elevation table
  • Vertical accretion


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