Hitchhiking Halophytes in Wrack and Sediment-Laden Ice Blocks Contribute To Tidal Marsh Development in The Upper Bay of Fundy.

Abstract Salt marshes are a type of coastal wetland that are affected by dynamic coastal processes. Ice blocks and wrack (mats of plant debris) regularly float onto northern marshes and become stranded, affecting vegetation and soil accretion. There is little research regarding the capacity of ice and wrack to transport viable plant propagules onto marshes where they can colonize, which may be particularly important at barren new salt marsh restoration sites. Contributions of sediment by ice may also be important at restoration sites to raise the marsh platform to elevations appropriate for plant colonization. We collected ice (n = 27) and wrack (n = 18) samples at marshes in the Bay of Fundy, ran germination trials with the contents, and measured the quantity of sediment in the ice. We found viable propagules from halophytic and non-halophytic species in wrack, and viable propagules of Sporobolus pumilus in ice. Additionally, we found sediment densities between 0.01 and 4.75 g·cm−3 in ice blocks that translated to 26.61 – 21,483.59 kg of total sediment per block, representing a large source of sediment. We found that the number of germinating propagules could not be predicted by wrack size, and that pH, sediment density, sediment weight in ice blocks were variable across the marsh surface, while ice salinity was negatively correlated with elevation and distance from creek. Our results indicate that ice and wrack represent a potential source for vegetation colonization at salt marsh sites and highlights their contributions to facilitating vegetation colonization through building marsh soils.

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Topological and Morphological Controls on Morphodynamics of Salt Marsh Interiors

Journal of Marine Science and Engineering ◽

10.3390/jmse9030311 ◽

2021 ◽

Vol 9 (3) ◽

pp. 311

Author(s):

Ben R. Evans ◽

Iris Möller ◽

Tom Spencer

Keyword(s):

Salt Marsh ◽

Salt Marshes ◽

East Coast ◽

Marsh Surface ◽

Coastal Environments ◽

Coastal System ◽

Morphological Segmentation ◽

The Usa ◽

The Uk ◽

Over Time

Salt marshes are important coastal environments and provide multiple benefits to society. They are considered to be declining in extent globally, including on the UK east coast. The dynamics and characteristics of interior parts of salt marsh systems are spatially variable and can fundamentally affect biotic distributions and the way in which the landscape delivers ecosystem services. It is therefore important to understand, and be able to predict, how these landscape configurations may evolve over time and where the greatest dynamism will occur. This study estimates morphodynamic changes in salt marsh areas for a regional domain over a multi-decadal timescale. We demonstrate at a landscape scale that relationships exist between the topology and morphology of a salt marsh and changes in its condition over time. We present an inherently scalable satellite-derived measure of change in marsh platform integrity that allows the monitoring of changes in marsh condition. We then demonstrate that easily derived geospatial and morphometric parameters can be used to determine the probability of marsh degradation. We draw comparisons with previous work conducted on the east coast of the USA, finding differences in marsh responses according to their position within the wider coastal system between the two regions, but relatively consistent in relation to the within-marsh situation. We describe the sub-pixel-scale marsh morphometry using a morphological segmentation algorithm applied to 25 cm-resolution maps of vegetated marsh surface. We also find strong relationships between morphometric indices and change in marsh platform integrity which allow for the inference of past dynamism but also suggest that current morphology may be predictive of future change. We thus provide insight into the factors governing marsh degradation that will assist the anticipation of adverse changes to the attributes and functions of these critical coastal environments and inform ongoing ecogeomorphic modelling developments.

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Top-down and sideways: Herbivory and cross-ecosystem connectivity shape restoration success at the salt marsh-upland ecotone

PLoS ONE ◽

10.1371/journal.pone.0247374 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0247374

Author(s):

Kerstin Wasson ◽

Karen E. Tanner ◽

Andrea Woofolk ◽

Sean McCain ◽

Justin P. Suraci

Keyword(s):

Salt Marsh ◽

Salt Marshes ◽

Camera Traps ◽

Physical Factors ◽

High Marsh ◽

Top Down ◽

Salt Marsh Restoration ◽

Marsh Restoration ◽

Restoration Site ◽

Restoration Success

Wetland restoration provides remarkable opportunities to understand vegetation dynamics and to inform success of future projects through rigorous restoration experiments. Salt marsh restoration typically focuses on physical factors such as sediment dynamics and elevation. Despite many demonstrations of strong top-down effects on salt marshes, the potential for consumers to affect salt marsh restoration projects has rarely been quantified. Recently, major restoration projects at the Elkhorn Slough National Estuarine Research Reserve in central California, USA provided an opportunity to examine how herbivory influences restoration success. We quantified the strength of consumer effects by comparing caged to uncaged plantings, and compared effects among plant species and sites. We used camera traps to detect which herbivores were most common and how their abundance varied spatially. Beyond characterizing consumer effects, we also tested management strategies for reducing negative effects of herbivory at the restoration sites, including caging, mowing, and acoustic playbacks of predator sounds. We found extremely strong consumer effects at sites with extensive stands of exotic forbs upland of the high marsh; uncaged restoration plants suffered heavy herbivory and high mortality, while most caged plants survived. Brush rabbits (Sylvilagus bachmani) were by far the most frequent consumers of these high marsh plants. Our work thus provides the first evidence of mammal consumers affecting salt marsh restoration success. Mowing of tall exotic forb cover adjacent to the marsh at one restoration site greatly reduced consumption, and nearly all monitored plantings survived at a second restoration site where construction had temporarily eliminated upland cover. Playbacks of predator sounds did not significantly affect restoration plantings, but restoration efforts in marsh communities vulnerable to terrestrial herbivory may benefit from concurrent restoration of predator communities in the upland habitats surrounding the marsh. A landscape approach is thus critical for recognizing linkages between terrestrial and marine vegetation.

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How do storm events and fair-weather conditions affect sedimentation patterns on salt marshes?

10.5194/egusphere-egu2020-10828 ◽

2020 ◽

Author(s):

Davide Tognin ◽

Mattia Pivato ◽

Andrea D'Alpaos ◽

Luca Carniello

Keyword(s):

Salt Marsh ◽

Salt Marshes ◽

Weather Conditions ◽

Marsh Surface ◽

Sediment Traps ◽

Vertical Accretion ◽

Storm Events ◽

Fair Weather ◽

Short Term ◽

Intense Storm

Coastal salt marshes are extremely important ecosystems, occupying the transitional zone between submerged and emerged environments. Since salt marshes are based on a delicate balance between hydrodynamics and sedimentary processes, their future is heavily affected by relative sea-level rise (RSLR), caused by both subsidence and eustatism. If vertical accretion is sufficient, salt marshes can keep pace with RSLR; otherwise, lack of sediment input can eventually lead to plant death and marsh drowning, transforming these landforms into tidal flats and subtidal platforms. Resuspension driven by intense meteorological events can represent an important source of sediment for salt marsh accretion in tidal environments characterized by negligible fluvial sediment supply. However, it is not yet clear what is the mutual role and relative contribution of intense storm events and fair-weather conditions in terms of sedimentation patterns. To better understand sedimentation dynamics on salt marshes, we stared a field campaign in October 2018 to measure vertical accretion rate and sediment accumulation.In the Venice lagoon (Italy), which is the largest lagoon in the Mediterranean sea and is characterized by a semi-diurnal, microtidal regime, we selected three study areas: the San Felice and Sant&#8217;Erasmo salt marshes in the northern lagoon and the Conche salt marsh in the southern lagoon. Subsidence at all these study sites ranges between 1.0 and 2.0 mm yr-1, and the rate of sea-level rise is of about 2.0 mm yr-1, for a total rate of RSLR of about 3.0-4.0 mm yr-1. At each study area, we considered different transects, where we installed three measurement stations located respectively at 2.5 m, 7.5 m, and 27.5 m from the salt marsh margin. We equipped each station with an artificial marker horizon laid down on the marsh surface to measure the vertical accretion, and three sediment traps for measuring the short-term sedimentation. The material deposited in two sediment traps is collected monthly or after any single storm, whereas sediment deposited in the third trap is collected once a year, in order to compare sediment deposition dynamics at short (single storm event) and annual time scales. We measure accretion rate, grain size distribution, organic and inorganic content.Short-term sedimentation displays a very high variability (0 &#8211; 320 g d-1 m-2) highlighting the importance of particularly intense storm events in resuspending and transporting sediment from tidal flats to the salt-marsh surface. In particular, during the storm events occurred in October 2018 and November 2019, sedimentation increases significantly and displays values much higher compared to fair-weather periods. According to our analysis, sedimentation grows exponentially with daily mean inundation time. Even if the inner part of the salt marsh is characterized by lower elevation and, hence, by greater inundation time, sedimentation shows smaller values compared to the salt marsh margin, since suspended material settles close to the margin and decreases towards the inner part of the marsh.

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GEOTECHNICAL PROPERTIES OF SALT MARSH AND TIDAL FLAT SUBSTRATES AT TILLINGHAM, ESSEX, UK.

Coastal Engineering Proceedings ◽

10.9753/icce.v36.papers.55 ◽

2018 ◽

pp. 55

Author(s):

Helen Brooks ◽

Iris MÃ¶ller ◽

Tom Spencer ◽

Kate Royse ◽

Simon James Price

Keyword(s):

Salt Marsh ◽

Systematic Study ◽

Salt Marshes ◽

Tidal Flat ◽

Marsh Surface ◽

Geotechnical Properties ◽

Surface Erosion ◽

Marsh Edge ◽

Erosion Risk ◽

Erosion Processes

Salt marshes and, to a lesser extent, tidal flats, attenuate incoming hydrodynamic energy, thus reducing flood and erosion risk in the coastal hinterland. However, marshes are declining both globally and regionally (the Northwest European region). Salt marsh resistance to incoming hydrodynamic forcing depends on marsh biological, geochemical and geotechnical properties. However, there currently exists no systematic study of marsh geotechnical properties and how these may impact both marsh edge and marsh surface erosion processes (e.g. surface removal, cliff undercutting, gravitational slumping). This has led to poor parameterization of marsh evolution models. Here, we present a systematic study of salt marsh and tidal flat geotechnical properties (shear strength, bulk density, compressibility, plasticity and particle size) at Tillingham, Essex, UK.

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Variability of vegetation in tidal marshes of Maine, U.S.A.

Canadian Journal of Botany ◽

10.1139/b89-032 ◽

1989 ◽

Vol 67 (1) ◽

pp. 230-238 ◽

Cited By ~ 18

Author(s):

Heather A. Jacobson ◽

George L. Jacobson Jr.

Keyword(s):

Species Richness ◽

Salt Marsh ◽

Species Composition ◽

New England ◽

Salt Marshes ◽

Tidal Marshes ◽

Bay Of Fundy ◽

Marsh Vegetation ◽

Southern New England ◽

England Salt Marsh

Systematic studies of vegetation on 18 salt marshes along the coast of Maine show that the vegetation is highly variable in species composition, species richness, and zonation pattern. Marshes with high species richness are found in relatively stable geologic settings, while unstable marshes at the base of erodible bluffs have low species richness. Species composition is influenced by freshwater input. Salt-marsh zonation varies greatly in both the number of zones present per marsh and the species assemblages within zones. With a few notable exceptions, the vegetation of salt marshes in southern Maine is similar to that of marshes in southern New England. Salt-marsh vegetation in northeastern Maine is more similar to that of marshes in the Bay of Fundy region. Key words: tidal marsh, salt marsh, Maine, vegetation, New England, Bay of Fundy.

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Fish Habitat: Essential Fish Habitat and Rehabilitation

Fish Habitat: Essential Fish Habitat and Rehabilitation ◽

10.47886/9781888569124.ch30 ◽

1999 ◽

Keyword(s):

United States ◽

Salt Marsh ◽

Marine Fish ◽

Salt Marshes ◽

Coastal Wetlands ◽

Life Histories ◽

Coastal Wetland ◽

Fish Habitat ◽

Northeastern United States ◽

Fishery Habitat

Abstract .—The importance of coastal wetlands to a large number of commercially important marine fish species for spawning, nursery, and foraging habitat is a commonly held belief. Few studies to substantiate this belief have been conducted in the northeastern United States. This paper examines in detail the life histories and habitat requirements of three species of fish commonly found in salt marshes in the northeastern United States. The results indicate that valuable commercial and recreational species of fish and their prey require coastal wetlands as habitat during their life cycles in New England. Coastal wetland restoration projects will increase the abundance of wetland habitat types required by commercial and recreational species of marine fish. The restoration of the salt marsh within the Galilee Bird Sanctuary in Narragansett, Rhode Island is used as case study. When enhancement of fishery habitat value is a goal of a restoration project, the project should incorporate certain design features. However, the designers of many salt-marsh restoration projects assume that reestablishment of salt-marsh vegetation will result in recolonization by other species of animals.

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Inoculating rhizome-propagated Sporobolus pumilus with a native mycorrhizal fungus increases salt marsh plant growth and survival

FACETS ◽

10.1139/facets-2020-0104 ◽

2021 ◽

Vol 6 ◽

pp. 1134-1145

Author(s):

Tyler W. d’Entremont ◽

Juan C. López-Gutiérrez ◽

Allison K. Walker

Keyword(s):

Salt Marsh ◽

Salt Marshes ◽

Large Scale ◽

Life Stage ◽

Mycorrhizal Fungus ◽

Arbuscular Mycorrhizal ◽

Nutrient Status ◽

Salt Marsh Restoration ◽

Growth And Survival ◽

Salt Marsh Plant

Salt marshes are ecosystems of significant ecological importance for coastal stability and fundamental roles in marine ecosystems. Salt marshes are declining due to anthropogenic and natural causes including sea level rise. Coastal restoration efforts have increased worldwide, but many fail in long-term coastal stability. We used a naturally occurring arbuscular mycorrhizal fungus (AMF) to test whether survival and early growth of the salt marsh grass Sporobolus pumilus (formerly Spartina patens) improved under simulated salt marsh conditions. Using a tidal mesocosm bench, we grew inoculated plants with varying AMF treatments under simulated tidal regimes to determine if AMF could aid in establishment of healthy Sporobolus communities. Rhizome-derived S. pumilus had greater survival and grew faster than seed-derived plants. Plants inoculated with propagated AMF consistently outperformed both sterile and native sediment controls in terms of plant survival and growth. Use of rhizome-derived Sporobolus inoculated with propagated Funneliformis geosporum showed the most promise in producing successful plant populations for salt marsh restoration. This may be due to plant life stage and improved plant nutrient status, allowing rhizome-derived plants to grow more quickly than seed-derived plants. Using these plants in future large-scale restoration may increase re-establishment of salt marsh ecosystems.

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Greenhouse gas flux with reflooding of a drained salt marsh soil

PeerJ ◽

10.7717/peerj.5659 ◽

2018 ◽

Vol 6 ◽

pp. e5659 ◽

Cited By ~ 1

Author(s):

Jan T. Wollenberg ◽

Asim Biswas ◽

Gail L. Chmura

Keyword(s):

Salt Marsh ◽

Salt Marshes ◽

Anthropogenic Impacts ◽

Ghg Emissions ◽

Eastern Canada ◽

Salt Marsh Restoration ◽

Marsh Soil ◽

Gas Flux ◽

Lawrence Estuary ◽

Tidal Flooding

Salt marshes are highly effective carbon (C) sinks and bury more C per square meter annually than any other ecosystem. Reclamation and anthropogenic impacts, however, have resulted in extensive losses of salt marshes. Carbon credits can be generated and sold by restoring marshes, but only if C sequestration and net reductions in greenhouse gases (GHG) are reliably quantified. Restored marshes, however, may exhibit different patterns of GHG emissions than natural marshes and it is possible that they could temporarily become sources of N2O even in the usually N-limited estuarine environment. Research on short-term GHG flux following salt marsh restoration is limited to studies of two restored marshes which examined GHG flux more than six months after the return of tidal flooding. Here we report on a laboratory experiment in which soil cores collected from a drained agricultural marsh on the St. Lawrence Estuary were flooded with estuary water. Gas flux measurements immediately after flooding revealed small increases in N2O and CH4, but a large decline in CO2 yielding, from a climatic perspective, a net cooling effect over the observation period. In addition to restoring the land’s capacity to sequester C once a marsh develops, returning tidal flooding thus appears to have the added benefit of stemming large ongoing C losses. With more than 400 km2 of undeveloped dykeland, Eastern Canada is well positioned to restore large sections of marsh and contribute to reducing atmospheric CO2 concentrations.

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Salt Marsh Restoration for the Provision of Multiple Ecosystem Services

Diversity ◽

10.3390/d13120680 ◽

2021 ◽

Vol 13 (12) ◽

pp. 680

Author(s):

Janine B. Adams ◽

Jacqueline L. Raw ◽

Taryn Riddin ◽

Johan Wasserman ◽

Lara Van Niekerk

Keyword(s):

Ecosystem Services ◽

Salt Marsh ◽

Salt Marshes ◽

Well Being ◽

Coastal Protection ◽

Degraded Land ◽

National Scale ◽

Salt Marsh Restoration ◽

Marsh Restoration ◽

Run Off

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.

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