Are Elevation and Open‐Water Conversion of Salt Marshes Connected?

Abstract Salt marsh assessments focus on vertical metrics such as accretion or lateral metrics such as open‐water conversion, without exploration of how the dimensions are related. We exploited a novel geospatial data set to explore how elevation is related to the unvegetated‐vegetated marsh ratio (...

Full description

Saved in:
Bibliographic Details
Main Authors: Neil K. Ganju, Zafer Defne, Sergio Fagherazzi
Format: Article
Language:English
Published: Wiley 2020-02-01
Series:Geophysical Research Letters
Online Access:https://doi.org/10.1029/2019GL086703
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract Salt marsh assessments focus on vertical metrics such as accretion or lateral metrics such as open‐water conversion, without exploration of how the dimensions are related. We exploited a novel geospatial data set to explore how elevation is related to the unvegetated‐vegetated marsh ratio (UVVR), a lateral metric, across individual marsh “units” within four estuarine‐marsh systems. We find that elevation scales consistently with the UVVR across systems, with lower elevation units demonstrating more open‐water conversion and higher UVVRs. A normalized elevation‐UVVR relationship converges across systems near the system‐mean elevation and a UVVR of 0.1, a critical threshold identified by prior studies. This indicates that open‐water conversion becomes a dominant lateral instability process at a relatively conservative elevation threshold. We then integrate the UVVR and elevation to yield lifespan estimates, which demonstrate that higher elevation marshes are more resilient to internal deterioration, with an order‐of‐magnitude longer lifespan than predicted for lower elevation marshes.
ISSN:0094-8276
1944-8007