Salt marsh monitoring along the mid-Atlantic coast by Google Earth Engine enabled time series

PLoS One. 2020 Feb 28;15(2):e0229605. doi: 10.1371/journal.pone.0229605. eCollection 2020.

Abstract

Salt marshes provide a bulwark against sea-level rise (SLR), an interface between aquatic and terrestrial habitats, important nursery grounds for many species, a buffer against extreme storm impacts, and vast blue carbon repositories. However, salt marshes are at risk of loss from a variety of stressors such as SLR, nutrient enrichment, sediment deficits, herbivory, and anthropogenic disturbances. Determining the dynamics of salt marsh change with remote sensing requires high temporal resolution due to the spectral variability caused by disturbance, tides, and seasonality. Time series analysis of salt marshes can broaden our understanding of these changing environments. This study analyzed aboveground green biomass (AGB) in seven mid-Atlantic Hydrological Unit Code 8 (HUC-8) watersheds. The study revealed that the Eastern Lower Delmarva watershed had the highest average loss and the largest net reduction in salt marsh AGB from 1999-2018. The study developed a method that used Google Earth Engine (GEE) enabled time series of the Landsat archive for regional analysis of salt marsh change and identified at-risk watersheds and salt marshes providing insight into the resilience and management of these ecosystems. The time series were filtered by cloud cover and the Tidal Marsh Inundation Index (TMII). The combination of GEE enabled Landsat time series, and TMII filtering demonstrated a promising method for historic assessment and continued monitoring of salt marsh dynamics.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Atlantic Ocean
  • Biomass*
  • Ecological Parameter Monitoring
  • Ecosystem*
  • Wetlands*

Associated data

  • figshare/10.6084/m9.figshare.11440968

Grants and funding

Y.W received funding from the National Park Service as part of grant number: NPS_P14AC00230. The funding organization website can be found at https://www.nps.gov/index.htm. Y.W. also received publication support from the Environmental Data Center at the University of Rhode Island funding organizations website can be found at https://www.edc.uri.edu/. A.D.C. received support from the NASA RI Space Grant. Funding organization website can be found at https://www.brown.edu/initiatives/ri-space-grant/. A.D.C. also received data access to in situ biomass estimates from the Virginia Coast Reserve Long-Term Ecological Research with support of NSF Grants BSR-8702333-06, DEB-9211772, DEB-9411974, DEB-0080381, DEB-0621014 and DEB-1237733. The organizations website can be found at https://www.vcrlter.virginia.edu/home2/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.