Salt Marsh Mapping and Change Analysis: Remote Sensing

Salt marshes provide a variety of ecosystem services including nursey ground for fish species, carbon storage and sequestration, and coastal resilience to storms and sea level rise (SLR). Loss of these important coastal ecosystems has been observed across the world including reclamation for agriculture, top-down pressure from herbivory, SLR, and eutrophication. The variety of stressors and unique data needs for salt marsh classification and monitoring positions remote sensing as an important tool for monitoring and furthering our understanding of salt marsh change. Salt marsh mapping has benefited from advances in land use or land cover mapping, the proliferation of very high spatial resolution (<1 m) commercial satellite imagery, and freely available medium-to-high resolution imagery. The multi-temporal classification and time series change analysis are emerging methodologies for conducting change analysis in salt marsh environments. This chapter presents a comparison of object-based and pixel-based classifications of salt marsh environments, use of very high spatial resolution and high resolution (10 m) imagery, and the use of Sentinel-2 NDVI time series to understand salt marsh change.