Salt Marsh Response to Inlet Switch‐Induced Increases in Tidal Inundation

Abstract

Salt marshes aggrade in quasi-equilibrium with sea level rise (SLR) via the accumulation of organic matter and mineral sediment, thereby maintaining marsh platform elevation within the tidal frame (e.g., Allen, 2000;Cahoon et al., 2019). External perturbations, such as an acceleration of relative SLR, can be compensated for by increased sediment delivery to the marsh platform. Increased inundation depth tends to augment sediment delivery as the associated longer flood duration increases time to trap suspended sediment (Day et al., 1999;Reed, 1990;Temmerman et al., 2003). In some cases, increased suspended sediment concentrations associated with land clearance has allowed marshes to recover from rapid SLR (Peck et al., 2020;Watson, 2004). In addition to increased mineral sediment delivery, there is some evidence that bioproductivity of low marsh grasses may increase with moderate increases in inundation, with subsequent vegetation drowning at higher levels of inundation (Morris et al., 2002;Voss et al., 2013). However, many studies have found declining biomass with increased

Biophysical Drivers of Coastal Treeline Elevation

“…Global climate models predict increases and decreases in future annual precipitation which will have a strong influence on estuarine salinity gradients. Similarly, tidal range may vary in the future based on changes in mean sea level and shoreline hardening (Blyth Lee et al., 2017; Cai et al., 2022), which is further complicated by shifts in storminess that cause barrier islands to form and breach, limiting or increasing tidal flushing (Yellen et al., 2023). Our work demonstrates a path forward to incorporating these complex and dynamic changes into future predictions of land use change by utilizing independently established ecosystem boundaries rather than static tidal datums.…”