Jump‐starting coastal wetland restoration: a comparison of marsh and mangrove foundation species

Abstract

During coastal wetland restoration, foundation plant species are critical in creating habitat, modulating ecosystem functions, and supporting ecological communities. Following initial hydrologic restoration, foundation plant species can help stabilize sediments and jump‐start ecosystem development. Different foundation species, however, have different traits and environmental tolerances. To understand how these traits and tolerances impact restoration trajectories, there is a need for comparative studies among foundation species. In subtropical and tropical climates, coastal wetland restoration practitioners can sometimes choose between salt marsh and/or mangrove foundation species. Here, we compared the early life history traits and environmental tolerances of two foundation species: (1) a salt marsh grass (Spartina alterniflora) and (2) a mangrove tree (Avicennia germinans). In an 18‐month study of a recently restored coastal wetland in southeastern Louisiana (USA), we examined growth and survival along an elevation gradient and compared expansion and recruitment rates. We found that the rapid growth, expansion, and recruitment rates of the salt marsh grass make it a better species for quickly establishing ecological structure at suitable elevations. The slower growth, limited expansion, and lower recruitment of the mangrove species show its restricted capacity for immediate structural restoration, especially in areas where it co‐occurs with perennial salt marsh species. Our findings suggest that the structural attributes needed in recently restored areas can be achieved sooner using fast‐growing foundation species. Following salt marsh grass establishment, mangroves can then be used to further assist ecosystem development. This work highlights how appropriate foundation species can help jump‐start ecosystem development to meet restoration objectives.

Frequency of extreme freeze events controls the distribution and structure of black mangroves (Avicennia germinans) near their northern range limit in coastal Louisiana

“…In addition to the risk that planted seedlings will be killed by extreme freezing temperatures, there is increasing evidence that salt marsh grasses (e.g., Spartina alterniflora ) are able to more effectively jump‐start coastal wetland restoration efforts compared to mangroves due to the more rapid growth, horizontal expansion and recruitment of marsh grasses compared to mangroves (specifically, A. germinans ; Yando, 2018; Yando, Osland, Jones, & Hester, 2019). Once established, planted salt marsh grasses can help trap mangrove propagules and facilitate the natural recruitment and growth of A. germinans seedlings (Donnelly, Walters, & coasts, 2014; Osland, Feher, Spivak, et al, 2020; Peterson & Bell, 2012).…”

Rapid peat development beneath created, maturing mangrove forests: ecosystem changes across a 25‐yr chronosequence

“…Created tidal wetlands in the region are typically excavated to a target tidal elevation and planted with salt marsh grasses to stabilize substrates, create immediate structural habitat, and jump‐start ecosystem development (Lewis and Dunstan , Yando et al. ). Then, tides and currents transport mangrove propagules from adjacent mangrove forests to the created wetlands, where natural recruitment and forest development begins within the first few years after wetland creation.…”

Organically Linking Green Development and Ecological Environment Protection in Poyang Lake, China Using a Social-Ecological System (SES) Framework

“…In addition, scholars have also analysed the basic characteristics and developmental requirements of the green industrial revolution and discussed the institutional thinking about the green economy; they have studied the impact of the green economic structure on the world using specific countries as examples and the relationship between green economy and smart growth under neoliberalism [ 8 , 9 , 10 ]. In the field of wetland conservation, in recent years, researchers have focused more on enhancing sustainable watershed management by developing policies to implement ecological restoration, assessing the impacts of conservation projects on wetland ecosystems using a conceptual model to define socio-economic vulnerability, and considering different stakeholder perspectives to enhance sustainable watershed management [ 11 , 12 , 13 , 14 , 15 ]. This provides an opportunity for organisations such as the Society of Wetland Scientists to raise the profile of wetlands and to initiate a discussion on how to respond to and change direction of the destructive development trajectory that led to wetland loss and degradation [ 16 ].…”