Multidisciplinary Marsh Characterization Informs Adaptive Restoration of Critical Riverine Estuary Habitat (Fowl River, Alabama, USA)

In 2016, marsh spits along Fowl River - an oligohaline estuary in coastal Alabama, USA - were identified by community members as a top restoration priority for the Mobile Bay National Estuary Program (MBNEP). To guide a directed restoration program, scientists, resource managers, engineers, and community members needed an improved understanding of the stressors underlying marsh degradation. The Fowl River Marsh Health Study (FRMHS) was conducted by an interdisciplinary team to assess factors influencing marsh loss and inform future restoration management decisions in the watershed. Results from the FRMHS indicated that chronic inundation from sea level rise (SLR; average water level > 5–10 cm above marsh surface), low accretion rates (avg 1.15 mm/yr), saltwater intrusion, and boat wake energy (> 20% of observations surpassing vegetation tolerances) are primary stressors degrading habitat in the estuary. Synthesized FRMHS findings were actively used to inform nearly all aspects of the restoration program; results and iterative community input stimulated co-produced, adaptive strategies for addressing large- and small-scale stressors affecting the sensitive marsh spits. Particularly, low accretion rates influenced the adoption of thin-layer placement (TLP) to mitigate past marsh loss (initial placement: 15–20 cm), with additional phases to adaptively raise marsh elevation in response to SLR (second placement: 20–25 cm). As a case study, the Fowl River restoration program illustrates the fruitful collaborations that can arise when a National Estuary Program facilitates a multidisciplinary scientific investigation, and demonstrates how purposeful co-production of knowledge guides and improves targeted restoration plans in under-researched estuarine ecotones.