Salt Marsh Restoration for the Provision of Multiple Ecosystem Services

Abstract

Restoration of salt marsh is urgent, as these ecosystems provide natural coastal protection from sea-level rise impacts, contribute towards climate change mitigation, and provide multiple ecosystem services including supporting livelihoods. This study identified potential restoration sites for intervention where agricultural and degraded land could be returned to salt marsh at a national scale in South African estuaries. Overall, successful restoration of salt marsh in some estuaries will require addressing additional pressures such as freshwater inflow reduction and deterioration of water quality. Here, we present, a socio-ecological systems framework for salt marsh restoration that links salt marsh state and the well-being of people to guide meaningful and implementable management and restoration interventions. The framework is applied to a case study at the Swartkops Estuary where the primary restoration intervention intends to route stormwater run-off to abandoned salt works to re-create aquatic habitat for waterbirds, enhance carbon storage, and provide nutrient filtration. As the framework is generalized, while still allowing for site-specific pressures to be captured, there is potential for it to be applied at the national scale, with the largest degraded salt marsh areas set as priorities for such an initiative. It is estimated that ~1970 ha of salt marsh can be restored in this way, and this represents a 14% increase in the habitat cover for the country. Innovative approaches to restoring and improving condition are necessary for conserving salt marshes and the benefits they provide to society.

Blue carbon benefits from global saltmarsh restoration

“…Li & Mitsch, 2016). In practice, the choice of restoration approach will be constrained by environmental context and may be directed by objectives other than carbon benefits, such as enhancing biodiversity and/or providing natural flood defence (Adams et al, 2021; Barbier et al, 2011).…”

“…Cost–benefit analysis accounting for ecosystem‐service gains show the cost of restoration is recovered within 5–30 years, for 20%–40% of projects, respectively, with small‐scale projects taking longer to recover expenses and increase in carbon value substantially reducing the timescale (Wang et al, 2022). Currently, only carbon has a significant market to help offset restoration costs and attract investors, but other saltmarsh ecosystem services, such as nutrient‐remediation and recreational space, have strong market potentials and unquestionable societal cost benefits (Adams et al, 2021; Lillebø et al, 2010; Wang et al, 2022).…”

“…Saltmarshes provide an array of other ecosystem services besides climate regulation, including delivering natural flood defence and water quality enhancement, and supplying habitat for biodiversity, commercial fish species and migratory birds (Adams et al, 2021; de la Barra et al, 2022; Fairchild et al, 2021; Sharps et al, 2017). In the United States, coastal wetlands were valued at US$23.2 billion year −1 for storm protection services alone (Costanza et al, 2008), and saltmarsh services globally are worth Int$1.07 trillion year −1 (Davidson et al, 2019, using 2007 ‘International’ $).…”

The Microbially Extended Phenotype of Plants, a Keystone against Abiotic Stress

“…In the face of increasing risks due to the effects of climate change, some ecosystem services, such as carbon storage by wetlands, take on unique value (46). Although the many ecosystem services these habitats provide are well known, they are globally at risk due to, e.g., agriculture, eutrophication, or land use (47,48).…”

Adventures of salt marsh recruits

“…Underpinned by the United Nations' call to action in "The UN Decade on Ecosystem Restoration" (cf. Waltham et al, 2020), restoration is gaining traction as a vital tool to reverse the degradation of salt marshes (Suding et al, 2015;Waltham et al 2020;Adams et al, 2021). Significant global efforts are urgently required to pin-point and generalize the mechanisms behind the dispersal, establishment, and persistence of salt marshes (Friess et al, 2012;Bouma et al, 2014;Temmink et al, 2020).…”