Seed Dispersal and Seedling Emergence in a Created and a Natural Salt Marsh on the Gulf of Mexico Coast in Southwest Louisiana, U.S.A.

Abstract

Early regeneration dynamics related to seed dispersal and seedling emergence can contribute to differences in species composition among a created and a natural salt marsh. The objectives of this study were to determine (1) whether aquatic and aerial seed dispersal differed in low and high elevations within a created marsh and a natural marsh and (2) whether seedling emergence was influenced by marsh, the presence of openings in the vegetation, and seed availability along the northern Gulf of Mexico coast. Aerial seed traps captured a greater quantity of seeds than aquatic traps. Several factors influenced aquatic and aerial seed dispersal in a created and a natural salt marsh, including distance from the marsh edge, cover of existing vegetation, and water depth. The natural marsh had a high seed density of Spartina alterniflora and Distichlis spicata, the low-elevation created marsh had a high seed density of S. alterniflora, and the highelevation created marsh had a high seed density of Aster subulatus and Iva frutescens. The presence of adult plants and water depth above the marsh surface influenced seed density. In the natural marsh, openings in vegetation increased seedling emergence for all species, whereas in the low-elevation created marsh, S. alterniflora had higher seedling density under a canopy of vegetation. According to the early regeneration dynamics, the future vegetation in areas of the low-elevation created marsh may become similar to that in the natural marsh. In the high-elevation created marsh, vegetation may be upland fringe habitat dominated by high-elevation marsh shrubs and annual herbaceous species.

Plant Community Establishment in a Coastal Marsh Restored Using Sediment Additions

“…At our site, S. alterniflora was the primary colonizing species and initially established during the first growing season through seed germination. Active seed dispersal mechanisms have been noted for S. alterniflora in Louisiana (Utomo et al 2009), with wind as the primary means for local dispersal (Elsey-Quirk et al 2009). Salt marsh restoration using sediment addition has been noted to increase sexual reproductive capacity in S. alterniflora at the patch scale (Jones et al 2019).…”

Modified sediments and subsurface hydrology in natural and recreated salt marshes and implications for delivery of ecosystem services

“…Post‐recreation monitoring generally focuses on re‐colonization by salt marsh vegetation and indicates that environmental enhancements can be achieved relatively quickly, as long as elevation and, hence, hydroperiod are suitable (Spencer and Harvey, ). However, there is growing evidence to demonstrate that the recreated salt marshes do not have the same biological characteristics as their natural counterparts with implications for their functioning and the ecosystem services that they provide (Garbutt and Wolters, ; Elsey‐Quirk et al, ; Mossman et al, 2012a,b). Such differences in species composition and diversity have been largely attributed to abiotic conditions such as redox, salinity and nutrient availability in the recreated sites (Erfanzadeh et al, ; Mossman et al , 2012a).…”

Biological Flora of Coastal Dunes and Wetlands:Borrichia frutescens(L.) DC.

“…Borrichia frutescens is a C 3 halophyte in carbon fixation with its light-independent reactions to photosynthesis (Antl- (Anonymous, 2013b;Thomas, 1993); VA ¼ Virginia (Harvill, 1965;Stalter and Lamont, 1990); NC ¼ North Carolina (Cleary, Hosier, and Wells, 1979;Kelley, 2006; Wright, Edwards, and van de Plassche, 2011); SC ¼ South Carolina (Luken, 2012;Stalter and Lamont, 1993;Stalter et al, 2006); GA ¼ Georgia (Antlfinger, 1981(Antlfinger, , 1982Antlfinger and Dunn, 1983;Guo and Pennings, 2012;Hanson, 1983;Pennings and Callaway, 2000;Richards, Pennings, and Donovan, 2005). (Anderson and Alexander, 1985;Schmidt et al, 2010;Stalter and Lynch, unpublished data;Stiling et al, 1992); MS ¼ Mississippi (Eleuterius, 1972;Elsey-Quirk, Middleton, and Proffitt, 2009;McCall and Pennings, 2012;Proffitt et al, 2005); LA ¼ Louisiana (Elsey-Quirk, Middleton, and Proffitt, 2009;McCall and Pennings, 2012;Proffitt et al, 2005); TX ¼ Texas (Abuzeineh et al, 2007;Alexander and Dunton, 2006;Feagin and Wu, 2006;Heinsch et al, 2004;Johnston, 1955;Lonard and Judd, 2002;Lonard et al, 2005;Marquardt and Pennings, 2011;Nelson et al, 2000;Stutzenbaker, 1999;…”