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Salt marsh

A salt marsh is a coastal wetland regularly flooded and drained by tides, featuring marshy soils composed of mud and peat with often low oxygen levels, and dominated by halophytic plants adapted to saline conditions.^[1] These ecosystems occur in low-lying intertidal zones along temperate and subtropical coastlines, where vegetation such as Spartina alterniflora in low marsh areas and Spartina patens in higher elevations forms dense stands that stabilize sediments and facilitate nutrient cycling.^[2] Salt marshes support high biodiversity, serving as nurseries for fish and shellfish, habitats for birds and invertebrates, and sites for carbon sequestration through belowground organic matter accumulation.^[3] They also provide coastal protection by attenuating wave energy and trapping sediments, though their persistence is challenged by sea-level rise and human development, which can alter hydrology and lead to habitat loss.^[4] Empirical studies highlight their role in filtering pollutants and enhancing water quality via microbial processes in anoxic soils.^[5]

Physical and Geological Features

Definition and Basic Characteristics

Salt marshes are coastal wetlands located in the upper intertidal zone, where they are periodically inundated by tides carrying saltwater or brackish water, and dominated by salt-tolerant herbaceous plants known as halophytes. These ecosystems form in sheltered coastal environments, such as estuaries, lagoons, or behind barrier islands, in areas protected from direct wave action. The substrate typically consists of fine-grained sediments, including mud and peat derived from decomposed plant material, which create waterlogged, anaerobic conditions.^[6]^[7] Key characteristics include a flat topography with elevations ranging from mean low tide to slightly above mean high tide, resulting in variable flooding frequencies that drive ecological zonation. Salinity fluctuates between 0.5% and 3.5% or higher during tidal cycles, with halophytes like Spartina alterniflora and Salicornia species exhibiting physiological adaptations such as salt excretion, succulent tissues, or pneumatophores to cope with osmotic stress, hypoxia, and sulfides. These plants form dense stands that trap suspended sediments, promoting vertical accretion rates of 1-10 mm per year in stable marshes.^[6]^[8]^[9] Salt marshes exhibit high primary productivity, often exceeding 1000 g C/m²/year, due to nutrient-rich tidal inputs and efficient recycling of organic matter, though productivity varies with latitude, hydroperiod, and nutrient availability. Unlike freshwater marshes, the persistent saline stress limits plant diversity to fewer than 20 species per site in many temperate systems, emphasizing specialized adaptations over broad competition. Microbial processes, including sulfate reduction, dominate decomposition in anoxic soils, influencing carbon storage and greenhouse gas emissions.^[6]^[10]

Formation Processes

Salt marshes primarily form in low-energy intertidal environments, such as estuaries, lagoons, or sheltered coastal bays, where fine-grained sediments like silt and clay are deposited by tidal currents and waves.^[11] These sediments originate from terrestrial sources via rivers or marine suspension, accumulating on tidal flats when hydrodynamic energy decreases sufficiently to allow net deposition.^[12] Formation requires a balance of sediment supply and accommodation space, with initial mudflat elevation reaching a threshold (typically 0.5–1 meter above mean low tide) that permits colonization by salt-tolerant pioneer vegetation.^[13] Once established, vegetation such as Spartina alterniflora in temperate regions plays a critical role in accelerating accretion through biomechanical stabilization and sediment trapping. Plant stems and roots reduce flow velocity, promoting the settling of suspended particles during tidal floods, while belowground organic matter contributes to peat accumulation, elevating the marsh surface.^[11] This creates positive feedbacks: increased elevation reduces inundation frequency, favoring higher-marsh species, and enhances overall sediment retention. Empirical measurements indicate vertical accretion rates of 2–4 mm per year in many systems, often matching or exceeding local sea-level rise rates of 1–3 mm per year, as observed in Pacific Northwest marshes (mean 3.6 mm yr⁻¹) and other sites.^[14] Tidal creeks and channels facilitate sediment transport into the marsh interior, with flood tides carrying particulates that settle on ebb as water levels drop. Storms episodically boost accretion by delivering coarser sediments and resuspending fines for redistribution, as evidenced by enhanced deposition following major events.^[15] However, excessive wave energy or sediment starvation can erode nascent marshes, limiting formation to protected settings. Faunal bioturbation, such as burrowing by crabs, can both enhance and hinder accretion by mixing sediments, though landscape-scale engineering by grazers may stimulate net elevation gain.^[16] Long-term persistence demands continuous vertical buildup to counter subsidence and sea-level rise, with rates varying spatially by 10–100 meters due to local hydrology and biology.^[14]

Sediment Trapping, Accretion, and Tidal Creeks

Salt marshes trap suspended sediments primarily during flood tides, when tidal waters inundate the vegetated platform, reducing flow velocities and allowing fine particles such as silts and clays to settle out of suspension.^[17] Vegetation, including species like Spartina alterniflora, acts as a baffle that dissipates wave energy and promotes flocculation of particles through biophysical interactions, enhancing deposition rates on the marsh surface and creek banks.^[18] This process is most effective in the low marsh zones, where higher inundation frequencies deliver greater sediment loads, with studies indicating that up to 80-90% of incoming suspended sediments can be retained under optimal hydrodynamic conditions.^[19] Vertical accretion occurs through the accumulation of these inorganic sediments alongside organic matter from plant roots and decomposition, enabling marshes to maintain elevation relative to sea level rise.^[20] Measured accretion rates vary by region and tidal regime but typically range from 2.3 to 9 mm per year in U.S. Atlantic and Gulf coast marshes, often exceeding local sea level rise rates of 2-4 mm per year and thus supporting long-term stability.^[21] In Pacific Northwest low intertidal marshes, mean rates average 3.6 mm per year (95% CI: 2.4-4.8 mm/yr), driven by both tidal deposition and bioturbation from burrowing organisms like crabs, which can amplify accretion by 20-50% through sediment reworking.^[22] However, compaction of underlying peat and autocompaction from organic decay can reduce net elevation gain by 30-50%, necessitating continuous sediment input to counteract subsidence.^[23] Tidal creeks form dendritic networks that channel flood and ebb flows, facilitating sediment import during high tides and selective export of finer fractions on the ebb, resulting in net deposition along creek margins.^[24] These creeks enhance overall marsh sediment dynamics by concentrating flow near banks, where velocities drop and deposition peaks, with studies showing elevated sediment concentrations and deposition rates proximal to creek edges during larger tidal amplitudes.^[25] In urban or high-energy settings, creeks can also entrain and redistribute internal marsh sediments, influencing platform morphology and preventing erosion, though altered hydrology from sea level rise may increase creek incision rates by 1-2 mm per year in vulnerable systems.^[26] Bioturbators and tidal asymmetry further modulate creek-mediated fluxes, with over 90% of net sediment exchange occurring during overbank flows in warmer seasons.^[27]

Global Distribution

Worldwide Occurrence

Salt marshes are distributed across all continents except Antarctica, primarily in low-energy, macrotidal to microtidal coastal environments where tidal inundation supports halophytic vegetation.^[28] They occur in sheltered estuaries, lagoons, and bays, with global mapping efforts identifying occurrences in 99 to 120 countries.^[29] ^[30] Recent satellite-based assessments estimate the global extent of tidal marshes, including salt marshes, at 52,880 km² as of 2020, with a 95% confidence interval of 32,030 to 59,780 km²; this figure represents a conservative update from prior estimates ranging up to 90,800 km², accounting for improved remote sensing and exclusion of unmapped regions.^[29] Approximately 40% of mapped salt marshes are concentrated along the Atlantic and Gulf coasts of North America, where they cover extensive areas in states like Louisiana, South Carolina, and Georgia, driven by high sediment supply from major river systems such as the Mississippi.^[31] ^[28] Europe hosts significant salt marshes along the Atlantic fringes, including the Wadden Sea and British Isles, while smaller but notable extents exist in the Mediterranean, Black Sea, and Baltic regions.^[3] In Asia, salt marshes are prevalent in temperate zones of China, Japan, and the Korean Peninsula, often fringing the Yellow Sea and Bohai Gulf, with additional occurrences in Southeast Asia transitioning to mangrove-dominated systems.^[28] Australia features salt marshes along its southern and eastern coasts, particularly in New South Wales and Victoria, covering thousands of hectares in estuarine settings.^[32] Africa and South America have more limited documented extents, concentrated in temperate southern regions like South Africa's Cape coast and Argentina's Río de la Plata estuary, though under-mapping in remote areas such as northern Russia suggests potential for higher totals.^[33] These distributions reflect climatic constraints, with salt marshes favoring temperate latitudes over tropical zones where woody mangroves typically dominate.^[34]

Regional Variations and Influencing Factors

Salt marshes exhibit significant regional variations in structure, extent, and species composition, primarily driven by differences in tidal regimes, climate, and geomorphology. In temperate North Atlantic regions, such as the eastern United States, marshes are often dominated by monospecific stands of Spartina alterniflora in low-elevation zones subject to frequent inundation, transitioning to S. patens in higher areas, reflecting adaptation to high salinity and strong tidal flushing.^[35] In contrast, European Atlantic marshes, including those in the United Kingdom and Netherlands, display greater floristic diversity with species like Puccinellia maritima, Elymus athericus, and Limonium vulgare, enabling more complex zonation patterns despite similar temperate climates.^[35] Pacific Coast marshes in North America, such as those in California, feature different dominants like Salicornia pacifica and Distichlis spicata, with reduced extent due to microtidal conditions (typically <2 m range) and higher wave energy, limiting sediment accumulation.^[36] Subtropical salt marshes, found in regions like southeast Australia and parts of the southeastern United States, incorporate more succulent chenopods such as Sarcocornia quinqueflora and Tecticornia perennis, alongside grasses, reflecting higher evaporation rates and seasonal salinity fluctuations that favor salt-excreting halophytes over the graminoid dominance of temperate zones.^[37] These variations correlate with latitudinal gradients, where warmer temperatures in subtropical areas (mean annual >15°C) support higher plant productivity but increase vulnerability to drought-induced die-offs, as observed in Florida marshes during prolonged dry periods.^[38] In macrotidal environments, such as the Bay of Fundy (tidal range up to 16 m), expansive marsh platforms develop with pronounced vertical zonation tied to elevation gradients of 1-2 m, whereas microtidal settings like the Mediterranean yield narrower, less stratified marshes confined to protected embayments.^[39] Key influencing factors include tidal amplitude, which controls hydroperiod and soil aeration; larger ranges (>4 m) promote deeper creek networks and sediment trapping, enhancing accretion rates of 2-10 mm/year, while smaller ranges restrict marsh seaward extent to <100 m.^[39] Climatic variables, such as temperature and precipitation, modulate salinity through evaporation and freshwater inputs, with subtropical marshes experiencing wider salinity swings (5-50 ppt) that select for stress-tolerant succulents.^[36] Geomorphological elements like sediment supply from adjacent rivers and coastal configuration further differentiate regions; for instance, sediment-rich deltas in the Gulf of Mexico support broader marshes than sediment-starved Pacific sites.^[36] Anthropogenic alterations, including dike construction in Europe reducing tidal exchange by up to 50% since the 19th century, exacerbate regional disparities by limiting natural accretion and promoting invasion by non-native species.^[35]

Ecological Zonation and Biota

Tidal Flooding and Vegetation Zonation

Tidal flooding in salt marshes follows semi-diurnal cycles, with inundation frequency and duration determined by marsh elevation relative to mean high water levels. Lower elevations experience regular flooding, often twice daily, leading to prolonged hydroperiods that impose physiological stresses such as anoxia and salinity fluctuations on biota. Higher elevations are flooded less frequently, primarily during spring tides or storms, resulting in shorter hydroperiods and greater aerobic soil conditions. These hydrological gradients, modulated by local tidal amplitudes typically ranging from 1 to 4 meters in temperate regions, form the primary axis for ecological structuring.^[40]^[41] Vegetation zonation emerges as plant species distribute along these elevational-hydroperiod gradients, with zonation patterns paralleling shorelines due to topographic contours. Low marsh zones, inundated for over 80% of tidal cycles, are dominated by Spartina alterniflora, a halophyte tolerant of frequent submersion and sulfide-rich sediments, where it facilitates sediment accretion through belowground biomass. Mid-marsh areas, flooded 30-80% of cycles, support Spartina patens and Distichlis spicata, species adapted to intermediate salinities and periodic drainage that mitigates anoxic stress. High marsh zones, flooded less than 30% of cycles, feature more diverse assemblages including Juncus gerardi and succulents like Salicornia spp., benefiting from reduced inundation that allows freshwater dilution and nutrient retention. Experimental manipulations confirm hydroperiod as the dominant control, overriding competition in structuring these bands, though salinity and elevation interact causally via drainage efficiency.^[42]^[43]^[44] Zonation stability depends on feedbacks between vegetation, sediment dynamics, and tidal energy; for instance, dense root mats in low marsh reduce erosion but can exacerbate die-off under prolonged inundation from sea-level rise. In microtidal systems, annual precipitation modulates effective hydroperiods, blurring zones compared to macrotidal settings. Peer-reviewed syntheses emphasize that while biotic factors like herbivory influence patchiness within zones, abiotic inundation metrics—frequency exceeding 200 events annually in low marsh versus under 50 in high marsh—primarily dictate species composition and marsh resilience to hydrological shifts.^[45]

Fauna, Herbivory, and Bioturbation

Salt marshes host diverse faunal communities adapted to periodic inundation and high salinity, including invertebrates, fish, birds, and mammals. Benthic invertebrates such as fiddler crabs (Uca spp.), ribbed mussels (Geukensia demissa), and periwinkle snails (Littoraria irrorata) form the foundation of the food web, with densities often exceeding thousands per square meter in creek banks.^[46]^[47] Juvenile fish including pinfish (Lagodon rhomboides), striped mullet (Mugil cephalus), and flounder utilize marshes as nursery grounds, seeking refuge among vegetation and feeding on invertebrates.^[47]^[48] Avian species like clapper rails, great egrets, and black ducks forage for prey, while mammals such as muskrats and raccoons exploit seasonal resources.^[49]^[50] Herbivory exerts significant control over vegetation dynamics, with key consumers including sesarmid crabs (Sesarma reticulatum), periwinkle snails, and belowground root feeders. In New England marshes, elevated densities of S. reticulatum—up to 100 individuals per square meter—have driven widespread die-off of smooth cordgrass (Spartina alterniflora) by clipping stems and consuming leaf tissue, exacerbating vulnerability to sea-level rise.^[51]^[52] This herbivory intensifies following predator declines, creating trophic cascades that reduce plant biomass by over 50% in affected areas.^[52] Snails graze on epiphytic algae and cordgrass blades, potentially limiting plant growth, though moderate levels may enhance productivity by controlling overgrowth.^[53] Belowground herbivory by nematodes and insect larvae further contributes to cordgrass mortality, with experimental exclusions showing up to 30% higher survival rates.^[54] Bioturbation by burrowing macrofauna, particularly fiddler and sesarmid crabs, profoundly alters sediment structure and biogeochemistry. These crabs excavate burrows extending 20-50 cm deep, turning over sediments at rates equivalent to 10-20 cm per year in high-density populations, which accelerates organic matter decomposition and nutrient remineralization.^[55]^[56] Such mixing enhances oxygen penetration and iron cycling but can diminish carbon storage by exposing buried organic carbon to oxidation, with models indicating up to 25% reductions under accelerated sea-level rise scenarios.^[57] In estuarine settings, bioturbation also influences erosion and accretion balances, stabilizing sediments through baffling effects while promoting particle resuspension during tidal flows.^[58] These processes underscore the dual role of faunal activity in marsh resilience and vulnerability.^[59]

Microbial Communities and Processes

Salt marsh sediments host diverse microbial communities dominated by bacteria, with archaea, fungi, and viruses also present, adapted to fluctuating salinity, oxygen levels, and organic inputs from vascular plants like Spartina alterniflora.^[60] Bacterial phyla such as Proteobacteria (including Gammaproteobacteria and Deltaproteobacteria), Bacteroidetes, and Firmicutes prevail, comprising the core microbiome that processes lignocellulosic detritus from marsh vegetation.^[60] Archaeal communities often feature high abundances of Crenarchaeota, exceeding 70% of sequences in grass-dominated sites, reflecting their tolerance for anoxic, sulfidic conditions.^[61] These assemblages vary spatially by sediment depth, tidal zonation, and seasonally, with alpha diversity stable across salinity gradients but beta diversity shifting due to environmental filtering.^[62] In rhizospheres, sulfur-cycling microbes predominate, linking plant roots to sediment geochemistry.^[63] Anaerobic microbial processes dominate due to periodic flooding and organic enrichment, with sulfate reduction by sulfate-reducing bacteria (SRB) serving as the primary pathway for organic carbon mineralization in saline sediments.^[64] SRB, often Deltaproteobacteria, oxidize acetate and hydrogen while reducing sulfate to sulfide, coupling to methane production or suppression via competition with methanogens.^[65] Denitrification, mediated by diverse bacteria under low-oxygen conditions, converts nitrate to dinitrogen gas, with rates elevated in vegetated zones exhibiting reducing redox potentials.^[43] This process competes with dissimilatory nitrate reduction to ammonium (DNRA), which predominates when sulfate is abundant, retaining nitrogen in bioavailable forms.^[66] Sulfur oxidation by chemolithoautotrophic bacteria further integrates carbon and nitrogen cycles, oxidizing sulfide to sulfate and fixing CO₂, thereby supporting primary production in anoxic layers.^[67] Nitrogen fixation occurs in association with sulfur cycling, particularly in S. alterniflora roots, where diazotrophs couple acetylene reduction to sulfide oxidation, enhancing plant nitrogen supply.^[68] Fungal communities, though less abundant, contribute to lignocellulose breakdown, with diversity increasing under erosional stress.^[69] Hydrology modulates these activities, masking warming effects on decomposition rates and preserving community resilience to temperature shifts.^[70] Overall, these microbes regulate nutrient retention and greenhouse gas emissions, with sulfate reduction suppressing methanogenesis and denitrification mitigating eutrophication.^[71]

Ecosystem Functions and Services

Nutrient Cycling and Decomposition

Salt marshes serve as dynamic interfaces for nutrient cycling, primarily involving nitrogen (N) and phosphorus (P), where tidal inundation introduces dissolved inorganic forms from upland runoff and coastal waters, followed by rapid uptake by halophytic vegetation such as Spartina alterniflora.^[71] Microbial communities in marsh sediments drive transformations, including ammonification of organic N during litter decomposition, nitrification under aerobic conditions at the soil surface, and anaerobic denitrification in deeper, waterlogged layers, which permanently removes N as dinitrogen gas (N₂).^[72] Denitrification rates in temperate salt marshes typically range from 50 to 500 μmol N m⁻² h⁻¹, influenced by nitrate availability and oxygen gradients, enabling marshes to retain or export 20–80% of incoming N depending on hydrology and vegetation cover.^[73] Phosphorus cycling contrasts, with P primarily immobilized through adsorption onto iron oxides and calcium phosphates in sediments, limiting bioavailability and export, though periodic anoxia can release bound P via reductive dissolution.^[74] Decomposition of vascular plant litter, dominated by graminoids like Spartina and Juncus species, is a core process recycling nutrients back into the system while contributing to soil organic matter buildup.^[75] Under frequent tidal flooding, decomposition proceeds slowly due to anoxic conditions, with sulfate-reducing bacteria outcompeting methanogens and denitrifiers for electron acceptors, yielding decay constants (k) of 0.001–0.005 d⁻¹ for Spartina alterniflora litter over 1–2 years.^[76] This anaerobic dominance preserves refractory carbon and nutrients in peat, enhancing marsh elevation and resilience, but nutrient enrichment from anthropogenic sources accelerates belowground decomposition, increasing CO₂ efflux by up to 2–3 times and shifting C turnover from sequestration to respiration.^[77] Macrofaunal bioturbation, such as by fiddler crabs, enhances oxygen penetration and organic matter turnover, stimulating N mineralization rates by 20–50% in burrowed zones.^[74] Environmental factors modulate these processes: elevated salinity inhibits microbial activity, reducing decomposition by 10–30% above 30 ppt, while warming under climate scenarios boosts initial litter breakdown by enhancing enzymatic hydrolysis, potentially releasing 15–25% more bioavailable N annually.^[78] In nutrient-limited systems, marshes act as sinks, burying 10–50 g N m⁻² yr⁻¹, but overloads promote dissimilatory nitrate reduction to ammonium (DNRA), recycling rather than removing N and exacerbating eutrophication downstream.^[72] Overall, decomposition efficiency varies more by litter quality—labile Spartina senesced leaves decompose faster than fibrous roots—than by inundation duration, underscoring plant species composition as a primary control on nutrient dynamics.^[76] These coupled cycles underpin marsh productivity, with recycled nutrients fueling 30–70% of secondary production in estuarine food webs.^[75]

Biodiversity Support

Salt marshes sustain a range of biodiversity adapted to saline, intertidal conditions, functioning as key habitats despite constraints on vascular plant diversity imposed by salinity and flooding. Vegetation communities exhibit low species richness, typically dominated by 2–5 halophytic graminoids and forbs such as Spartina alterniflora in low-marsh zones and Juncus roemerianus or Spartina patens in higher elevations, with overall plant species counts per site often below 10 in temperate regions and even lower in tropical settings.^[40]^[79] This limited flora nonetheless provides critical structural cover, organic substrate, and primary production that underpin faunal communities. Invertebrate diversity thrives in the sediment and plant matrix, with marshes hosting hundreds of species including fiddler crabs (Uca spp.), ribbed mussels (Geukensia demissa), snails (Littoraria irrorata), and polychaetes, which bioturbate soils and form the base of detrital food webs.^[46] These organisms benefit from the marsh's productivity, with densities enhanced by tidal flushing and algal epiphytes on vegetation. Fish utilization is pronounced, as salt marshes offer nursery habitat, refuge from predators, and foraging grounds for over 75% of U.S. commercial and recreational fisheries species, including juvenile shrimp, blue crabs, and finfish like menhaden (Brevoortia spp.).^[1]^[80] Bird species richness is supported through seasonal migration stopovers, nesting sites in emergent vegetation, and abundant prey; wading birds such as great egrets (Ardea alba) and clapper rails (Rallus crepitans) forage on exposed mudflats and creeks for fish and invertebrates during low tides.^[81]^[49] Mammalian and reptilian presence is sparser but includes muskrats (Ondatra zibethicus) for herbivory and diamondback terrapins (Malaclemys terrapin) reliant on crab and snail populations. The mosaic of ponds, creeks, and pannes within marshes fosters microhabitat variability, elevating overall species richness and resilience via connectivity to adjacent estuarine and marine ecosystems.^[82]^[83]

Carbon Sequestration and Coastal Protection

Salt marshes function as significant carbon sinks within coastal ecosystems, primarily through the burial of organic matter in waterlogged, anoxic soils where microbial decomposition is inhibited, leading to long-term accumulation. These systems, classified as blue carbon habitats alongside mangroves and seagrasses, sequester atmospheric carbon at rates approximately 10 times higher than mature tropical forests per unit area, driven by high plant productivity from species like Spartina alterniflora and sediment trapping during tidal inundation.^[84]^[85] Global estimates indicate soil organic carbon stocks in salt marshes averaging 42–317 Mg C ha⁻¹, with much stored belowground; for instance, Chinese salt marshes hold about 317 Mg C ha⁻¹ in soils compared to only 9 Mg C ha⁻¹ in biomass.^[86]^[87] Recent studies show sequestration rates increasing with relative sea-level rise, as accelerated sedimentation enhances organic carbon accumulation; one New England site recorded rates doubling to around 129 g C m⁻² yr⁻¹ in the past decade versus historical averages of 46 g C m⁻² yr⁻¹ from 550–1800 CE.^[88]^[89] However, marsh degradation can reverse this, releasing stored carbon and potentially turning sites into sources, underscoring the need for conservation to maintain sequestration efficacy.^[90] In addition to carbon storage, salt marshes provide coastal protection by dissipating wave energy and attenuating storm surges through vegetation drag and sediment stabilization. Vegetated marsh platforms reduce incident wave heights by 30–90% over distances of several hundred meters, with attenuation strongest at the marsh edge where dense stems and roots impede flow; this effect persists even during extreme events with elevated water levels.^[91]^[92] For storm surges, marshes can decrease floodwater levels by over 30% inland, as demonstrated in modeling of tidal systems where surge propagation is damped by frictional losses in vegetated zones.^[93] Empirical data from restored or natural marshes indicate that maintaining at least 50% vegetation cover in the first 100 m offshore yields substantial wave energy reduction during storms, thereby shielding adjacent shorelines from erosion and infrastructure damage.^[94] Integrating marshes with engineered structures like levees further lowers protection costs globally by leveraging natural wave dissipation, though effectiveness depends on marsh width, plant density, and hydrodynamic conditions.^[95] These protective services are empirically linked to marsh accretion rates matching or exceeding sea-level rise, preventing submergence and sustaining barrier functions over decadal scales.^[96]

Economic and Fisheries Value

Salt marshes provide substantial economic value through their support for commercial and recreational fisheries, functioning as essential nursery, feeding, and refuge habitats for juvenile stages of many harvested species. Approximately 75% of U.S. fisheries species, including finfish, shrimp (Penaeus spp.), and blue crabs (Callinectes sapidus), depend on coastal marshes for these roles, enhancing recruitment and survival rates that underpin harvestable populations.^[97] Estuaries, which incorporate salt marshes, account for habitat supporting 68% of the U.S. commercial fish catch and 80% of recreational catch, with salt marsh vegetation and detritus contributing to food webs that boost productivity.^[80] In specific U.S. regions, this habitat function translates to measurable fisheries output. South Carolina's commercial fisheries, reliant on marsh-derived productivity, generate $42 million annually and sustain 840 jobs, dominated by shrimp landings that correlate with marsh area and health.^[97] Tidal marshes in Virginia's Middle Peninsula, through fisheries habitat and related recreation, contribute to $90 million in yearly economic value across communities, with projections indicating potential growth to $168 million by 2050 under marsh expansion scenarios.^[98] Nationally, coastal wetlands including salt marshes bolster fisheries sectors that, in 2018, drove $238 billion in sales impacts and 1.7 million jobs, though attribution to marshes specifically requires accounting for overlapping estuarine habitats.^[99] Beyond direct fisheries landings, salt marshes enable economic gains from recreational angling, valued in studies of southeastern U.S. wetlands at millions per marsh area for angler expenditures tied to marsh-supported stocks.^[100] Internationally, U.K. salt marshes support 15% to 17.5% of commercial landings for European seabass (Dicentrarchus labrax), demonstrating habitat dependence in export-oriented fisheries.^[101] These values underscore causal links from marsh productivity to fishery yields, with empirical models linking marsh loss to declines in juvenile densities and adult catches, though quantification varies by species and region due to migration and multi-habitat use.^[102]

Human Interactions

Historical Reclamation and Land Use

Salt marshes have long been viewed as marginal lands suitable for conversion to more productive uses, with reclamation efforts dating back to the Middle Ages in Europe, where diking and drainage transformed wetlands into agricultural fields to expand arable territory.^[103] These practices intensified during the 17th and 18th centuries, driven by population growth and the need for farmland, often involving the construction of embankments to exclude tidal waters and enable grazing or crop cultivation. In regions like the Wadden Sea, land reclamation for agriculture represented the primary driver of salt marsh decline over centuries, reducing marsh extents through systematic enclosure and drainage.^[104] In southern Europe, such as the Arade estuary in Portugal, dyke construction and direct reclamation for agriculture resulted in the loss of more than half of salt marsh areas between approximately 1800 and 2010, with peak activity in the 19th and early 20th centuries before mid-1960s abandonment of some diked lands allowed partial natural recovery.^[105] Similar transformations occurred in France's Arcachon Bay during the late 18th century, where portions of salt marshes at the Leyre River mouth were reclaimed for salt production via polderization, altering geomorphology and sediment dynamics.^[106] These efforts prioritized short-term economic gains from intensified land use over long-term ecological stability, frequently leading to soil salinization that limited sustained agricultural viability. In North America, European settlers initiated salt marsh reclamation as early as the late 17th century, with dikes built along Delaware Bay in 1675 to exclude saltwater and create pastureland from tidal wetlands.^[107] By the 18th and 19th centuries, extensive diking and filling in coastal New Jersey converted thousands of acres of marsh into hay fields and meadows, a process documented in historical surveys showing progressive enclosure for salt-hay production without full drainage in some cases.^[108] In New England, marshes supported commercial salt-hay farming through selective ditching for improved access and drainage, a practice that persisted into the 20th century but avoided wholesale reclamation until urban pressures mounted; the New Jersey Wetlands Act of 1970 subsequently halted new reclamations while permitting maintenance of existing hay operations.^[109] Beyond agriculture, historical land use included mosquito control via grid-ditching in the early 20th century, particularly in the U.S. Northeast, which inadvertently drained marshes and altered hydrology, and conversion to salt works or urban fill in various locales. In California, reclaimed marshlands peaked in agricultural use during the early 20th century before economic shifts led to state acquisition for conservation by the 1930s, encompassing around 200 such sites.^[110] These reclamations, while boosting local economies temporarily, often disregarded the marshes' roles in flood buffering and sediment trapping, contributing to downstream erosion and habitat fragmentation.^[108]

Pollution from Agriculture and Urbanization

Agricultural runoff introduces excess nutrients, primarily nitrogen and phosphorus from fertilizers, into salt marshes, often exceeding the ecosystems' assimilative capacity and triggering eutrophication. A 2016 study at the Virginia Institute of Marine Science demonstrated that while low-level nutrient additions initially enhance plant growth, concentrations mimicking coastal runoff—such as 100 micromoles per liter of nitrate—overwhelm microbial denitrification processes, reducing nitrogen removal efficiency by up to 50% and altering sediment biogeochemistry.^[111] This overload promotes algal blooms that smother benthic habitats and leads to hypoxic conditions, diminishing habitat quality for infaunal communities. Pesticides from agricultural fields, including herbicides like atrazine, enter marshes via surface runoff, persisting in anaerobic sediments where degradation rates slow, amplifying toxicity to salt-tolerant plants like Spartina alterniflora and associated invertebrates.^[112] Sediment-laden runoff from croplands erodes marsh edges and buries rhizomes, contributing to vegetation die-off; for instance, U.S. Department of Agriculture assessments indicate that improper tillage and over-fertilization on coastal farms mobilize 10-20 tons of sediment per hectare annually into adjacent wetlands during storm events.^[113] These inputs disrupt belowground decomposition dynamics, as evidenced by a nine-year field experiment showing that chronic phosphorus enrichment elevates soil organic matter accumulation but suppresses root biomass by 30%, weakening marsh stability against erosion.^[114] Urbanization exacerbates pollution through stormwater conveyance systems that channel contaminants directly to marshes, bypassing natural dilution. Heavy metals such as copper, zinc, and lead from vehicular emissions and roofing materials accumulate in sediments, with concentrations in urban-influenced marshes reaching 100-500 mg/kg for zinc—levels toxic to microbial nitrogen cyclers and macrofauna.^[115] A 2018 peer-reviewed analysis of Australian salt marshes found that nutrient-enriched urban runoff (total nitrogen >5 mg/L) favors invasive freshwater sedges over native halophytes, compressing salt marsh zonation by 20-40% within decades.^[116] Pathogenic bacteria and endocrine-disrupting compounds from sewage overflows further impair water quality, correlating with elevated coliform counts exceeding 10,000 CFU/100mL in tidally flushed urban creeks.^[117] Combined agricultural and urban inputs synergistically degrade marsh functions; for example, nutrient-metal interactions enhance bioavailability, as chelated forms increase uptake in primary producers, cascading to bioaccumulation in herbivores like ribbed mussels (Geukensia demissa).^[118] Empirical monitoring in U.S. East Coast estuaries reveals that sites with >20% impervious urban cover and adjacent farmland exhibit 2-3 times higher pollutant loads than pristine analogs, correlating with 15-25% declines in Spartina cover over 20 years.^[119] Despite tidal flushing mitigating some episodic runoff, chronic loading overwhelms filtration, underscoring marshes' finite buffering against anthropogenic stressors.^[120]

Development Pressures and Trade-offs

Salt marshes experience significant development pressures from coastal urbanization, infrastructure expansion, and port activities, which often involve direct filling, diking, or dredging to create usable land. In the United States, historical conversion has been extensive; for instance, much of Boston's Back Bay was originally tidal salt marsh filled in during the 19th century for urban expansion.^[121] Similarly, Rhode Island has lost over 50% of its salt marshes in the past 200 years primarily due to such coastal development.^[122] These activities convert marsh habitats into residential, commercial, or industrial zones, with global salt marsh losses totaling 561 square miles between 2000 and 2020, partly attributable to land reclamation for human use.^[123] Infrastructure projects exacerbate these pressures by restricting natural marsh dynamics. Bulkheads and seawalls, installed to protect upland development, prevent landward marsh migration and accelerate erosion, resulting in net marsh loss up to 180% greater in affected areas compared to unconstrained sites.^[124] Dredging for ports and navigation channels disrupts sediment supply, while road and railway construction fragments habitats and alters hydrology. In New Jersey, such development combines with other factors to threaten remaining tidal marshes, historically reclaimed for agriculture and urban purposes.^[125] Trade-offs arise between short-term economic gains from development and the long-term value of marsh ecosystem services. Reclaimed coastal land supports urbanization, industry, and agriculture, providing immediate revenue and housing, but at the cost of forgone benefits like flood mitigation—salt marshes in New Jersey reduce annual flood losses by 16%—and non-carbon services valued at approximately $2,537 per acre annually.^[125]^[126] Carbon sequestration alone averages $1,863 per acre yearly, with total discounted values diminishing under development scenarios that ignore sea-level rise vulnerabilities.^[126] While proponents of development emphasize job creation and property values, empirical assessments highlight undervalued externalities, such as heightened flood risks to adjacent infrastructure, underscoring causal links between habitat loss and increased coastal hazards.^[127]

Environmental Challenges

Sea Level Rise and Marsh Resilience

Salt marshes counteract sea level rise (SLR) through vertical accretion, a process involving the deposition of mineral sediments during tidal inundation and the buildup of organic matter from plant roots and decomposition. Empirical measurements from sediment cores indicate accretion rates typically ranging from 1 to 10 mm per year across global coastal systems, influenced by factors such as tidal range, suspended sediment concentrations, and vegetation density. For example, a 2020 modeling study of U.S. Atlantic marshes reported mean initial accretion of 3.45 ± 0.83 mm/yr, with rates up to 9.28 mm/yr in low-elevation zones receiving higher sediment loads.^[128] These rates have historically matched or exceeded local relative SLR, which averages 3-4 mm/yr globally but varies with subsidence and regional ocean dynamics.^[21] Recent empirical studies demonstrate variable resilience, with many marshes adapting via accelerated accretion in response to SLR. Analysis of East Coast U.S. sites using marker horizons and cores showed some platforms gaining elevation faster than the 20th-century SLR rate, attributed to increased tidal sediment trapping by dense Spartina vegetation.^[129] Similarly, 2023 research emphasized sediment supply as pivotal, with marshes in high-delivery environments (e.g., near river mouths) maintaining balance through biogeomorphic feedbacks where plant roots stabilize deposits and enhance organic accumulation.^[130] However, sediment deficits from upstream dams and erosion reduce inputs, causing lags; for instance, Georgia marshes have transitioned to open water where accretion falls below 2 mm/yr.^[131] Subsidence exacerbates this in tectonically active or organically rich marshes, where compaction of peat lowers platforms over time.^[20] Projections of future resilience hinge on SLR acceleration and local conditions, with models indicating thresholds beyond which drowning occurs. Under intermediate SLR scenarios (e.g., 5-8 mm/yr by 2100), sediment-limited marshes may fragment into "doughnut-like" patterns, with edges accreting faster than interiors due to wave exposure.^[132] A 2023 global modeling effort predicted over 90% of marshes could submerge by century's end even under conservative SLR, assuming static sediment dynamics, though this overlooks potential increases from storm frequency or restoration.^[133] Empirical counter-evidence from long-term monitoring suggests nonlinear dynamics, where initial submergence triggers feedbacks like enhanced mineral deposition, allowing persistence in systems with adequate hydrology.^[20] Inland migration offers another pathway, but coastal development often blocks it, amplifying vulnerability.^[134] Overall, resilience depends causally on sediment budgets exceeding SLR plus compaction losses, with human alterations to watersheds critically determining outcomes.^[135]

Mosquito Control and Other Management Conflicts

Salt marshes serve as significant breeding grounds for mosquito species such as Aedes taeniorhynchus and Aedes sollicitans, which oviposit eggs on moist soil rather than standing water, leading to mass emergences that pose public health risks including nuisance biting and potential disease vectors like West Nile virus.^[136] Early 20th-century responses involved extensive grid ditching to drain pooled water and facilitate larval desiccation, a practice implemented across U.S. East Coast states from the 1920s onward, which moderately reduced populations but caused substantial ecological disruption including vegetation die-off, accelerated erosion, altered tidal hydrology, and declines in fish and bird populations dependent on intact marsh structure.^[137]^[138] These interventions, driven by public health imperatives, exemplified causal trade-offs where short-term pest suppression undermined long-term ecosystem stability, prompting regulatory scrutiny under frameworks like the U.S. Clean Water Act by the 1970s.^[139] Contemporary strategies emphasize Open Marsh Water Management (OMWM), a source-reduction technique introduced in the 1980s that modifies high-marsh areas by excavating irregular ponds and radial ditches to enhance tidal flushing, introduce predatory fish like mummichogs (Fundulus heteroclitus), and eliminate mosquito-friendly depressions without broad impoundment or chemical reliance.^[140]^[141] Implemented in regions such as New Jersey, Delaware, and Florida, OMWM has demonstrated reductions in larval salt marsh mosquito densities by up to 90% in treated plots compared to untreated grids, while partially restoring habitats degraded by prior ditching through improved water circulation.^[142] However, empirical assessments reveal conflicts: pond creation can shift vegetation from dense Spartina grasses to open water, potentially diminishing carbon sequestration and favoring alternative mosquito species or non-native invasives; subsurface water level drawdowns have been linked to localized plant stress in some sites, though tidal restoration often mitigates broader salinity imbalances.^[143]^[144] Integrated Mosquito Management (IMM) supplements OMWM with targeted larvicides like Bacillus thuringiensis israelensis (Bti), which selectively targets dipteran larvae with minimal non-target effects on vertebrates or beneficial invertebrates, as evidenced by decades of European and U.S. applications showing no detectable impacts on salt marsh biodiversity metrics such as bird nesting success or fish recruitment.^[145]^[141] Yet, management tensions persist in reconciling these tactics with conservation mandates; for instance, Florida's salt marshes have seen protracted disputes since the 1980s between mosquito control districts and environmental agencies over OMWM permitting, where habitat alterations risk violating wetland protection statutes unless offset via mitigation banking, which may inadvertently prioritize preservation over adaptive pest control.^[146]^[147] Other conflicts arise from competing uses, such as prescribed burns for vegetation management that inadvertently boost mosquito production by creating temporary breeding pools, or recreational pressures that fragment OMWM sites, underscoring the need for site-specific empirical monitoring to avoid unintended exacerbation of vector habitats.^[148]^[149]

Restoration and Management

Techniques and Empirical Outcomes

Hydrological restoration, involving the breaching of dikes or removal of impoundments to reinstate tidal inundation, constitutes a primary technique for salt marsh recovery, often enabling natural vegetation recolonization without extensive planting.^[150] Vegetation planting, typically using plugs, shoots, or sods of native species such as Spartina alterniflora, addresses areas with limited propagule sources, with nursery-raised plants achieving high establishment rates in projects like those in Tampa Bay, where annual production supports revegetation of approximately 5 acres.^[151] ^[150] Thin-layer placement of dredged sediment raises marsh elevation to counter subsidence or sea-level rise, as demonstrated in initiatives like the University of Florida's St. Augustine project aimed at enhancing erosion resistance.^[150] Complementary measures include invasive species removal, fertilization with nitrogen or phosphorus, and protective structures like netting to mitigate herbivory or wave exposure.^[151] ^[152] Empirical assessments reveal variable success, with a global meta-analysis of 1,038 planting efforts reporting a mean survival rate of 53% ± 37% across genera, where higher rates (e.g., 79% for Puccinellia) correlate with dense, locally sourced, multi-species plantings and site protections, while failures stem from erosion, hypersalinity, or direct seeding (13 studies).^[151] Restored marshes exhibit elevated sediment trapping, accruing 185.71 ± 56.35 tons per hectare per year more than natural counterparts, yielding accretion rates of 19.58 ± 6.66 mm/year in salt marshes, primarily driven by antecedent sediment supply exceeding 20 g/m³ rather than tidal range or wave height. Soil organic carbon accumulation matches natural rates at 64.26 ± 7.54 g/m²/year post-restoration, increasing stocks by 10.70 ± 3.45 Mg C/ha relative to degraded sites, though biodiversity metrics lag, with vegetation richness 0.41 effect size lower and macrobenthos 0.23 lower than references.^[151] Functional recovery develops gradually, often failing to fully equate natural marshes even after years, with restored sites showing greater variability in metrics like elevation change (10.35 ± 1.56 mm/year).^[151] Global projects, concentrated near megacities (e.g., New York, Shanghai) and major rivers (e.g., Mississippi, Yangtze), favor large-scale hydrological and vegetation methods for cost-effectiveness, with per-hectare expenses for planting 10–20 times higher than passive approaches, yet 20% recouping costs in under 5 years via services like flood mitigation.^[152] Success hinges on matching restored hydrology to historical patterns, as mismatches constrain vegetation trajectories, underscoring sediment dynamics and site-specific stressors as causal determinants over generalized interventions.^[151] ^[152]

Successes, Failures, and Criticisms

Restoration efforts in salt marshes have achieved measurable successes in vegetation recovery and habitat enhancement when hydrological connectivity is prioritized. For instance, in a New England project initiated in 2020, the restoration of surface drainage channels reversed subsidence-induced vegetation loss, recovering multiple acres of marsh within three years by reinstating tidal flows that supported sediment deposition and plant recolonization.^[153] Globally, a meta-analysis of 54 studies found that planted marshes exhibited higher restoration outcomes than unplanted degraded sites, with average plant survival rates of 53% across diverse projects, particularly when site-specific factors like elevation and species selection were optimized.^[154] These gains often include rapid increases in biodiversity, such as enhanced bird and fish populations, as evidenced by post-restoration monitoring in Hurricane Sandy-funded initiatives, where ecosystem integrity indices improved through sediment nourishment and breaching of impoundments.^[155] Failures frequently stem from unaddressed external stressors overriding local interventions, such as excessive nutrient loading or wave energy that erodes newly planted vegetation. In the Liaohe River Estuary, despite restoration attempts, vegetation communities collapsed twice due to watershed-scale pollution mismatches, with recovery limited by ongoing eutrophication that favored algal blooms over marsh grasses.^[156] Hurricane-induced damage, as seen in Florida's Big Bend region following Hurricane Michael in 2018, demonstrated rapid marsh degradation through debris burial and scouring, where pre-existing restoration sites lost up to 30% of cover without subsequent recovery due to compounded erosion.^[157] Resource constraints have also doomed projects, such as certain California tidal marsh restorations that languished post-implementation, reverting to invasive-dominated states from inadequate maintenance amid budget shortfalls.^[158] Criticisms highlight the high financial costs and uncertain long-term viability of many initiatives, particularly amid accelerating sea-level rise. Systematic reviews indicate that while projects can recoup expenses through ecosystem services like flood mitigation—estimated at $10,000–$50,000 per hectare annually in some U.S. cases—they often exceed $100,000 per hectare in upfront costs, with benefits skewed toward short-term metrics like plant cover rather than full functional recovery.^[152] Skeptics argue that overreliance on passive techniques like tidal reconnection ignores persistent threats from climate variability, as drought episodes in restored Australian marshes halved colonization rates over multi-year monitoring from 2020 onward.^[159] Furthermore, some evaluations question the scalability of successes, noting that positive outcomes in controlled, small-scale studies (e.g., 175-foot experimental plots) fail to translate to larger landscapes due to invasive species proliferation and hydrological mismatches, underscoring a need for more rigorous, watershed-integrated assessments beyond anecdotal reporting.^[160]^[161]

Economic Evaluations and Policy Implications

Economic evaluations of salt marsh restoration typically employ benefit transfer methods, avoided cost analyses for flood protection, and valuations of ecosystem services such as carbon sequestration, water purification, and fisheries support, yielding per-acre values ranging from $1,863 for carbon benefits to $2,537 for non-carbon services in regions like Narragansett Bay, Rhode Island.^[162] A global systematic review of restoration projects spanning 1980–2020 found average costs of approximately $50,000–$100,000 per hectare, with benefits often exceeding expenses through enhanced resilience to erosion and storm surge reduction, though profitability varies by site-specific hydrology and sediment supply.^[152] ^[163] In the UK, meta-regression analyses estimate salt marsh habitats deliver annual values up to £10,000–£20,000 per hectare across services like coastal defense and recreation, supporting arguments for investment despite upfront dredging and planting expenditures.^[164] Cost-benefit analyses reveal trade-offs, as restoration yields long-term gains—such as $90 million annually in ecosystem services equivalent to 3.3% of regional GDP in some coastal areas—but initial outlays can delay returns by decades if marshes fail to accrete sediment against sea level rise.^[165] Empirical data from U.S. projects indicate net positive returns when factoring in flood damage avoidance, estimated at $10,000–$50,000 per acre protected, yet critics note over-reliance on modeled valuations that undervalue maintenance costs or ignore opportunity costs like forgone development revenue.^[166] Recent studies emphasize integrating uncertainty from climate projections, projecting salt marsh values could decline 20–50% by 2100 without adaptive management, underscoring the need for dynamic economic models over static appraisals.^[126] Policy implications center on incentivizing restoration through regulatory frameworks like the U.S. Clean Water Act and Coastal Zone Management Act, which mandate mitigation for wetland losses and promote dredged sediment reuse via thin-layer placement techniques approved in state guidelines as of 2024.^[167] Governments increasingly adopt nature-based solutions, allocating funds—such as U.S. Fish and Wildlife Service grants for runnel digging and peat rebuilding—to leverage marshes' flood mitigation over hardened infrastructure, potentially saving billions in disaster recovery as demonstrated in post-Hurricane Sandy assessments.^[168] However, policies must address local values, with urban restoration succeeding when aligned with resident preferences for biodiversity over pure flood control, implying subsidies or carbon markets could bridge funding gaps but risk inefficiency if not tied to verifiable outcomes like accretion rates.^[169] International guidelines advocate site-specific monitoring to avoid maladaptation, recommending public-private partnerships to scale projects amid fiscal constraints.^[170]

Research Methods and Recent Developments

Field and Modeling Approaches

Field studies of salt marshes typically employ transect-based sampling to quantify vegetation zonation, species composition, and biomass, using methods such as interrupted belt transects and quadrat sampling to capture spatial variability in halophyte cover and diversity.^[171] Hydrological parameters, including inundation frequency and soil salinity, are measured via piezometers, tide gauges, and sediment traps, while biotic assessments integrate core sampling for belowground root biomass and faunal populations.^[172] Recent plot-scale comparisons have validated point-intercept transects against visual cover estimation techniques like Braun-Blanquet and Floristic Quality Assessment (FQA), finding point-intercept methods more precise for percent cover but labor-intensive, with FQA excelling in rapid integrity evaluations of marsh condition.^[173] Rapid assessment protocols, such as MarshRAM, streamline vulnerability indexing by scoring erosion, wrack deposition, and creek density through field metrics, enabling efficient monitoring across large areas without extensive equipment.^[174] Emerging field techniques incorporate remote sensing integration, where unoccupied aerial vehicles (UAVs) with structure-from-motion (SfM) photogrammetry generate 3D models of vegetation height and canopy structure, calibrated against ground-truthed elevation data to map microtopography and biomass at centimeter resolution.^[175] Multi-tiered monitoring frameworks, as proposed for regional programs, combine intensive core-site instrumentation (e.g., continuous salinity loggers) with extensive visual surveys and opportunistic citizen data to track long-term changes in elevation and accretion.^[176] These approaches prioritize empirical validation of causal drivers like sediment supply and tidal energy, avoiding overreliance on proxy indicators prone to confounding variables. Modeling efforts simulate salt marsh dynamics through process-based frameworks that couple hydrodynamics, sediment transport, and vegetation feedbacks, such as finite-difference schemes resolving tidal flows, wave attenuation, and organic matter decomposition to predict platform evolution over decadal scales.^[177] Data-driven models leverage machine learning on field datasets to classify features like salt patches or pool expansion, achieving high accuracy in delineating stress zones when trained on hyperspectral and topographic inputs.^[178] Recent advances include spatiotemporal vegetation modules in biogeomorphic models, which account for seasonal growth and die-off to forecast marsh progradation under varying sediment budgets, outperforming static equilibrium assumptions in scenarios with sea-level rise.^[179] Hybrid approaches integrate field-derived parameters into predictive tools, like minimalist ecological models driven by inundation thresholds to simulate halophyte zonation and internal deterioration, validated against Chesapeake Bay observations showing sediment deficits amplify drowning risks by 20-50% under 3-5 mm/yr rise rates.^[180]^[181] Coupled hydrodynamic-biogeomorphic simulations reveal trade-offs in ecosystem services, where increased inundation erodes soil shear strength, potentially halving carbon burial rates in vulnerable platforms, as parameterized from empirical accretion cores.^[182] These models emphasize causal linkages, such as bio-stabilization reducing erosion by 30-70% via root reinforcement, but highlight uncertainties in allochthonous inputs amid anthropogenic alterations.^[183]

Key Findings from 2023-2025 Studies

A 2025 study modeling internal marsh deterioration found that sea-level rise, subsidence, and sediment deficits lead to submergence and open-water expansion, with predictive models identifying early thresholds for marsh platform collapse based on observed elevation deficits exceeding 1-2 mm/year relative to local sea-level rise rates.^[181] Similarly, analysis of belowground biomass across U.S. coastal marshes revealed a widespread decline since 2014, with reductions up to 30-50% in root and rhizome densities serving as an early indicator of drowning risk, particularly in sediment-limited systems where vertical accretion fails to match inundation increases.^[184] In Maine marshes, remote sensing data from 2009-2021 documented a 15.7% expansion in pool area, primarily from mega-pool coalescence, correlating with reduced vegetation cover and heightened vulnerability to erosion under accelerated tidal flooding.^[185] Carbon sequestration dynamics showed enhancement under certain conditions; a 2025 investigation in subtropical marshes demonstrated that accelerated sea-level rise rates (above 5 mm/year) boosted organic carbon accumulation by 20-40% in levee zones compared to basins, driven by increased plant productivity and burial efficiency despite higher decomposition risks.^[186] Restoration efforts post-invasive species removal, such as Spartina alterniflora, yielded improved sequestration, with native saltmarsh recovery increasing soil carbon stocks by 15-25% within 2-5 years through enhanced root biomass and reduced methane emissions, though long-term gains depended on hydrological reconnection.^[90] Globally, 2024 assessments of tidal marsh soils quantified average carbon densities at 100-200 Mg C/ha in the top 1 m, with accumulation rates varying 50-150 g C/m²/year, but spatiotemporal heterogeneity up to 63% across elevations and seasons underscored the influence of salinity gradients and hydroperiod on net storage.^[187]^[188] Restoration techniques emphasized context-specific hydrology; a 2025 evaluation of runnel-based hydrologic restoration reported accelerated decomposition of organic matter (rates 10-20% higher post-intervention), facilitating sediment trapping but risking short-term carbon loss before stabilization, with empirical outcomes showing 60-80% recovery in plant cover after 3 years in impounded systems.^[189] In drought-prone restorations, 2025 field trials indicated climate sensitivity, with plant colonization rates dropping 40-60% during prolonged dry periods, highlighting trade-offs in trajectory success under variable precipitation regimes.^[159] Projections for Mediterranean marshes under 2025 scenarios predicted near-total loss by 2100 without sediment augmentation, as elevation deficits outpace accretion by 2-5 mm/year, emphasizing the limits of natural resilience in low-sediment supply contexts.^[190]

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Plants and Animals of a North Florida Salt Marsh
May 24, 2010 · Fiddler crabs (Uca sp.) · Pinfish (Lagodon rhomboides) · Ribbed mussel (Geukensia demissa) · Striped mullet (Mugil cephalus).
[48]
Exploring Atlantic Salt Marshes from the Ground Up
May 27, 2025 · Juvenile Atlantic sturgeon, striped bass, redfish, Atlantic silversides and flounder find shelter and abundant food in the shallow, grassy ...Missing: fauna | Show results with:fauna
[49]
6 Types of Wildlife and Plants That Thrive in Salt Marshes
Mar 22, 2021 · Some visitors to the salt marshes include the osprey, bald eagle, black duck, great blue heron, marsh wren, belted kingfisher, and clapper rail, ...
[50]
Tidal Salt Marshes - Florida Wetlands Extension Program - UF/IFAS
Apr 7, 2025 · Popular mammal species in the marsh are Louisiana muskrat and marsh rabbit, while the cotton rat and rice rat live in the upland, and raccoons, ...Missing: fauna | Show results with:fauna
[51]
The effects of Sesarma reticulatum (L.) herbivory and sea level rise ...
High densities of herbivorous purple marsh crabs (Sesarma reticulatum) have caused major vegetation loss in salt marshes across Cape Cod (Massachusetts, USA).
[52]
Herbivory Drives the Spread of Salt Marsh Die-Off - PMC
Mar 20, 2014 · Salt marsh die-off is being largely driven by intense herbivory via the release of herbivorous crabs from predator control.
[53]
[PDF] Salt Marsh Food Web
May 20, 2020 · They feed on algae, bacteria, salt marsh cordgrass, and plant detritus. Periwinkles are eaten by fish, crabs, birds, and small mammals.
[54]
Belowground herbivory increases vulnerability of New England salt ...
Sep 1, 2012 · 1). These patterns suggest that belowground herbivory can potentially drive local patterns of aboveground cordgrass mortality in marshes with ...
[55]
Bioturbation of Burrowing Crabs Promotes Sediment Turnover and ...
Oct 11, 2025 · Crab burrowing in salt marshes can mix surface and deeper soil over a period of years, accelerating litter decomposition and promoting the ...
[56]
[PDF] JOURNAL OF MARINE RESEARCH - EliScholar
Mar 21, 2003 · Bioturbation by fi ddler crabs largely determines sediment reworking rates in the creek bank and Borrichia habitats. Additionally, fi ddler ...
[57]
Crab bioturbation reduces carbon storage in salt marshes under ...
Jun 10, 2024 · Crabs, such as fiddler crabs and Sesarmidae crabs, have significant impacts on sediment carbon cycling in coastal saltmarshes (Andreetta et al. ...
[58]
Bioturbation impacts on sediment accretion and erosion in tidal ...
Oct 6, 2025 · Bioturbators can influence accretion and erosion processes in tidal marshes by either stabilizing or destabilizing sediment. Through this ...Missing: mixing animals
[59]
Effects of population density on the sediment mixing induced by the ...
By modifying the physical, chemical and biological sediment properties, the bioturbation activities of the organisms within soft sediments play a major role in ...
[60]
Mechanistic strategies of microbial communities regulating ...
Feb 17, 2021 · Salt marshes are major natural repositories of sequestered organic carbon with high burial rates of organic matter, produced by highly ...
[61]
Archaeal Diversity and the Prevalence of Crenarchaeota in Salt ...
Crenarchaeal 16S rRNA sequences constituted over 70% of the archaeal clones recovered from three salt marsh sites dominated by different grasses.Missing: microbiome | Show results with:microbiome
[62]
Salinity Effect on Soil Bacterial and Archaeal Diversity and Assembly ...
May 29, 2025 · While the bacterial and archaeal alpha diversity showed no significant differences among the three salt marshes, the community composition ...
[63]
The core root microbiome of Spartina alterniflora is predominated by ...
Mar 1, 2022 · The core root microbiome of Spartina alterniflora is predominated by sulfur-oxidizing and sulfate-reducing bacteria in Georgia salt marshes, USA.Primary Productivity... · Microbiome Diversity · Discussion
[64]
Microbial chemolithoautotrophs are abundant in salt marsh ...
Aug 4, 2023 · Anaerobic fermentation and sulfate reduction are the primary processes used by the microbial community to mineralize these organic carbon ...Results · Chemolithoautotroph... · Discussion
[65]
Elevated CO2 and high salinity enhance the abundance of sulfate ...
Among diverse microbial communities, sulfate reducing bacteria (SRB) play a crucial role in organic matter decomposition in saline environments such as salt ...
[66]
Simultaneous sulfate and nitrate reduction in coastal sediments - PMC
Mar 8, 2023 · Therefore increases in sulfate reduction rate in-situ may result in enhanced DNRA and reduced denitrification rates. Intriguingly, the shift ...
[67]
The Role of Sulfur Oxidizing Bacteria in Salt Marsh C and N Cycling
The project focuses on sulfur-oxidizing bacteria, a group of particularly important chemosynthetic microbes that use energy trapped in sulfur compounds in ...
[68]
Sulfur oxidation and reduction are coupled to nitrogen fixation in the ...
Apr 29, 2024 · The core root microbiome of Spartina alterniflora is predominated by sulfur-oxidizing and sulfate-reducing bacteria in Georgia salt marshes, USA ...Results · Methods · Nitrogen Fixation Rates<|separator|>
[69]
Bacterial and fungal communities exhibit contrasting patterns in ...
Marsh erosion had contrasting effects on soil bacterial and fungal communities. Bacterial diversity decreased but fungal diversity increased with marsh erosion.
[70]
Hydrology Masks Warming Effects on Microbial Communities in Salt ...
Oct 11, 2025 · Soil microbial communities play a pivotal role in salt marsh ecosystem functioning, driving processes such as organic matter decomposition ...
[71]
Salt marsh nitrogen cycling: where land meets sea - ScienceDirect
The core root microbiome of Spartina alterniflora is predominated by sulfur-oxidizing and sulfate-reducing bacteria in Georgia salt marshes, USA. Microbiome.Salt Marshes Are Hot Spots... · N Fixation · Nitrification
[72]
The Nitrogen Removal Ability of Salt Marsh Improved After Grazing ...
Jul 17, 2022 · This study assessed the impact of grazing prohibition on potential rates of nitrification and denitrification under short- and long-term grazing prohibition.
[73]
6 - The Role of Marshes in Coastal Nutrient Dynamics and Loss
Several features of salt marshes play an important role in how nutrient are cycled. One is that most vegetated marshes accrete sediments. The structure of the ...
[74]
Salt marsh macrofauna: An overview of functions and services
Salt marshes are globally important blue carbon ecosystems, providing essential services such as coastal protection, carbon sequestration, nutrient cycling, ...
[75]
[PDF] Litter Decomposition of Spartina alterniflora and Juncus roemerianus
Decomposition of plant litter in salt marshes plays an important role in coastal trophodynamics, nutrient cycling, sediment trapping, and short-term carbon ...
[76]
Salt marsh litter decomposition varies more by litter type than by ...
Nov 9, 2024 · The litter decomposition varied only between the inundation treatments with the longest and shortest durations, while the decomposition differed significantly ...<|separator|>
[77]
High nutrient loads amplify carbon cycling across California and ...
Sep 9, 2022 · The higher nutrient load marshes were characterized by faster carbon turnover, with higher belowground production and decomposition and greater carbon dioxide ...
[78]
Warming accelerates belowground litter turnover in salt marshes - BG
May 24, 2023 · Peer review ... This finding suggests that warming may accelerate carbon and nutrient cycling through stimulated initial decomposition ...
[79]
Ecological resilience indicators for salt marsh ecosystems
Salt marshes are coastal ecosystems within the intertidal zone, characterized by hypoxic, saline, soil conditions and low biodiversity.
[80]
Estuary Habitat - NOAA Fisheries
Estuaries provide habitat for about 68 percent of the U.S. commercial fish catch and 80 percent of recreational catch. Estuaries are also a major stopover point ...
[81]
Dynamics of the Salt Marsh
On the rising tide, many species of fish and aquatic invertebrates invade small creeks and tidal flats to prey on resident animals and each other. As the tide ...
[82]
Salt Marshes - American Littoral Society
Salt marshes are coastal wetlands. They are important habitat for numerous bird, fish, and invertebrate species providing both food and habitat. salt ...
[83]
Saltmarsh - Farm Wildlife
The habitat also provides nurseries for spawning fish and important feeding areas for migrating birds. Scare Pug larvae on Sea Wormwood (c) ...
[84]
Protecting Coastal Blue Carbon Through Habitat Conservation
Sep 4, 2025 · Research shows that mangroves and salt marshes remove (sequester) carbon from the atmosphere at a rate 10 times greater than tropical forests.
[85]
Coastal Blue Carbon - NOAA's National Ocean Service
Jun 25, 2024 · Coastal salt marshes, mangroves, and seagrass beds are incredibly efficient at capturing and storing large quantities of carbon – referred ...
[86]
The blue carbon of southern southwest Atlantic salt marshes ... - NIH
Dec 22, 2023 · Several mechanisms driven by burrowing crabs affect the OC cycle in SW Atlantic salt marshes, either through herbivory or bioturbation. These ...Missing: animals | Show results with:animals
[87]
Coastal blue carbon in China as a nature-based solution toward ...
Jul 21, 2023 · Salt marshes are among the most productive ecosystems, which store substantially more C in soils (317 ± 19 Mg C ha−1) than in plant biomass (9 ± ...
[88]
Increased sea level rise accelerates carbon sequestration ... - PubMed
Jan 1, 2025 · Our results reveal that the salt marsh site experiencing the accelerated RSLR rates shows OCAR values that are on average twice as high as those found in the ...<|separator|>
[89]
[PDF] Salt marsh ecosystem restructuring enhances elevation resilience ...
Nov 9, 2018 · Carbon storage was. 46 ± 28 g C/m2/yr from 550 to 1800 CE, increasing to 129 ± 50gC/m2/yr in the last decade. Enhanced carbon storage is ...
[90]
Restoration of native saltmarshes enhances carbon sequestration ...
Jun 25, 2025 · The results showed that S. alterniflora removal drastically reduced carbon sink, with unrestored mudflat transitioning to a carbon source. While ...<|control11|><|separator|>
[91]
Review of methods for quantifying the benefits of coastal wetlands in ...
Mangroves and tidal marshes can reduce wave energy by 30–90% and coastal flooding by over 30%, protecting properties and preventing shoreline erosion (Smith ...Missing: peer | Show results with:peer
[92]
Wave attenuation over coastal salt marshes under storm surge ...
Oct 1, 2014 · We find that the presence of marsh vegetation causes considerable wave attenuation, even when water levels and waves are highest. From a ...
[93]
Evidence on the performance of nature-based solutions ...
Dec 2, 2024 · Attenuation of storm surge by mangrove forests [111] and marshes [1, 30] may also contribute to coastal protection by substantially decreasing ...
[94]
How Much Marsh Restoration Is Enough to Deliver Wave ... - Frontiers
Feb 6, 2022 · This study found a substantial reduction in storm wave energy when the first 100 m of a marsh is at least 50% vegetated, though lifespan ...
[95]
Cutting the costs of coastal protection by integrating vegetation in ...
Nov 11, 2021 · We evaluate the use of coastal vegetation, mangroves, and marshes fronting levees to reduce global coastal protection costs, by accounting for wave-vegetation ...Coastal Vegetation Presence · Wave Attenuation By Coastal... · Results On Country Level
[96]
Researchers Connect Satellite and Soil Data to Refine Salt Marsh ...
Mar 5, 2025 · Salt marshes act as long-term carbon sinks, continuously accumulating carbon as tides and storms deposit sediment into dense marsh grasses.
[97]
Valuing Ecosystem Services of Coastal Marshes and Wetlands
Jan 20, 2020 · A California study estimated that the carbon sequestration value of salt marsh ranges between $56 and $1,861 ha-1 yr-1.9 These studies are not a ...
[98]
Study finds coastal wetlands generate $90 million annually for ...
Aug 19, 2025 · A new study led by William & Mary's Batten School & VIMS shows that tidal marshes generate approximately $90 million annually in economic ...
[99]
Coastal Wetland Habitat - NOAA Fisheries
Salt marshes, seagrass beds, and mangroves play an important role in removing greenhouse gases like carbon dioxide from the atmosphere and storing them in ...
[100]
The economic valuation of saltwater marsh supporting marine ...
This paper is concerned with placing an economic value on the contribution of wetlands in supporting recreational fishing in the southeastern United States.
[101]
Using a residency index to estimate the economic value of coastal ...
Feb 23, 2021 · Saltmarsh is a nursery habitat for many commercially important fish species, including European seabass (Dicentrarchus labrax) in the UK ...
[102]
[PDF] Dependence of Fishery Species on Salt Marshes: The Role of Food ...
Knowledge of relative importance of the food and refuge functions in support of living resources is of practical value in marsh and fisheries management.
[103]
[PDF] Centuries of Human-Driven Change in Salt Marsh Ecosystems
Aug 28, 2008 · Here, we review historic and contem- porary human activities in marsh ecosystems—exploitation of plant prod- ucts; conversion to farmland, salt ...
[104]
Salt marshes - Wadden Sea Quality Status Report
The major cause for their decline during historical times has been land-claim to acquire new land for agriculture, and more recently, coastal-protection ...
[105]
The impacts of land-use changes on the recovery of saltmarshes in ...
Between c. 1800 and 2010 more than half of saltmarshes were lost due to dyke building and saltmarsh reclamation for agriculture. In mid-1960s, the abandonment ...
[106]
Geomorphological Effects of Land Reclamation in the Eighteenth ...
Jan 29, 1991 · During the second half of the 18th century, large parts of the salt marshes at the Leyre River mouth in Arcachon Bay were converted into salt ...
[107]
The Complicated History of Our Marshes and an Update on ...
Aug 23, 2023 · As early as 1675, settlers arriving on the Delaware Bay built dikes in salt marshes to protect land from saltwater inflow and create an ...
[108]
From Marsh to Farm (Chapter 1) - National Park Service
Jan 31, 2005 · A detailed history of land reclamation in New Jersey, beginning with a general overview of the biology of tidal wetlands, and specifically salt marshes.
[109]
chapter 5: salt-hay farming - National Park Service
Jan 31, 2005 · The Wetlands Act of 1970 bars the reclamation of new tracts of marshland, but does allow farmers to maintain what is already used for salt-hay ...
[110]
[PDF] 2.222 (2) Historic Reclamation of Marshlands. The preservation of ...
With the decline of agriculture in the 30's nearly all reclaimed marshlands were purchased by the State of California. Department of Fish and Game and some 200 ...
[111]
Study reveals salt marshes have limited ability to absorb excess ...
Nov 7, 2016 · These ecosystems can receive excess concentrations of nutrients such as nitrogen from wastewater and runoff of agricultural fertilizer. This ...
[112]
Effects of pesticides and road salt on freshwater quality and nutrient ...
Road salts alter freshwater pH, turbidity, and dissolved oxygen levels. Pesticides degrade slower and become more toxic in altered water conditions.
[113]
Reducing the Impact of Farming on Water Quality - USDA ARS
Jan 10, 2025 · This runoff can carry sediment, nutrients, and pesticides into neighboring waterways. Water can also infiltrate the soil and percolate ...
[114]
[PDF] Saltmarsh plant responses to eutrophication
We implemented an ecosystem- scale, nine- year nutrient exper- iment to examine how saltmarsh plants respond to simulated conditions of coastal eutrophica- tion ...
[115]
Heavy metal compartmentalisation in salt marsh and seagrass of the ...
Urbanised and industrialised estuaries face heavy metal pollution. · Seagrass has potential as bioindicator and accumulator of metals. · Salt marsh species are ...
[116]
Urban stormwater run-off promotes compression of saltmarshes by ...
Oct 1, 2018 · In urbanised catchments, saltmarsh areas receive nutrient-enriched and pollutant-contaminated run-off, such as heavy metals, through the ...
[117]
Urban Stormwater: An Overlooked Pathway of Extensive Mixed ...
Aug 21, 2019 · Urban stormwater runoff has been identified as a leading cause of waterway impairment for many pollutants, but there has been a lack of research ...
[118]
Heavy Metal Pollution in Coastal Environments: Ecological ... - MDPI
Urban runoff is another major contributor, transporting heavy metals from roads, buildings, and urban infrastructure into coastal wetlands [14]. Heavy metals ...
[119]
Urban stormwater run-off promotes compression of saltmarshes by ...
In urbanised catchments, saltmarsh areas receive nutrient-enriched and pollutant-contaminated run-off, such as heavy metals, through the stormwater system. This ...
[120]
Limited Influence of Urban Stormwater Runoff on Salt Marsh ...
Overall, rainfall and runoff per se were not associated with differences in the oxygen dynamics among the different locations. Because of the large tidal range ...Missing: pollution peer
[121]
Ecology and Vulnerability Coastal: Salt marsh
Many low-lying coastal urban areas such as Boston were previously salt marshes, but were filled in with sediment for development purposes. Salt marsh adaptation ...
[122]
Tracking Salt Marshes: Impacts of Sea Level Rise - NOAA Sea Grant
Nov 10, 2014 · Over the past 200 years, Rhode Island has lost over 50 percent of its salt marshes due to coastal development, resulting in a loss of ...Missing: statistics | Show results with:statistics
[123]
NASA Scientists Map Global Salt Marsh Losses and Their Carbon ...
Dec 7, 2022 · According to a new NASA-led study, the world has lost 561 square miles (1,453 square kilometers) of salt marshes over the past 20 years.Missing: statistics | Show results with:statistics
[124]
Investigating the Impacts of Landward Bulkheads on Salt Marshes
Jul 28, 2025 · Net marsh loss was, on average, 180 percent greater where bulkheads were present. Salt marshes have a natural tendency to shift and migrate in ...Missing: development statistics
[125]
[PDF] Status and Future of Tidal Marshes in NJ Faced with Sea Level Rise
They estimated salt marshes reduced annual flood losses by 16%, with greater reductions at lower elevations. With reduced marsh acreage and more intense ...
[126]
[PDF] Economic Value of Salt Marshes under Uncertainty of Sea Level Rise
Jun 10, 2022 · Coastal and estuarine salt marshes provide a diverse spectrum of valuable ecosystem services, including water filtration, nutrient cycling,.<|control11|><|separator|>
[127]
Economic and ecological trade-offs of coastal reclamation in the ...
Coastal reclamation promotes coastal urbanization, industrial and agricultural development. Due to the physical characteristics of land use in reclamation areas ...
[128]
Modeling long‐term salt marsh response to sea level rise in ... - ASLO
Apr 14, 2020 · The mean initial vertical accretion rate from 300 model runs was 3.45 ± 0.83 mm yr−1, with higher rates reaching 9.28 ± 1.11 mm yr−1 at lower ...
[129]
Some coastal salt marshes are keeping up with sea level rise
Mar 28, 2023 · New research reveals how salt marshes along the U.S. East Coast have responded to accelerating sea level rise by building elevation more quickly ...
[130]
Sediment Plays Key Role in Helping Salt Marshes Endure Sea ...
Feb 6, 2023 · Researchers found that salt marshes may be able to endure rising sea levels with the help of an unlikely hero: sediment.
[131]
Salt marshes losing race to rising sea level - Skidaway Institute of ...
Dec 12, 2022 · Salt marshes have been able to stay ahead of the rising sea level by adding sediment carried to the marsh and deposited there by river discharge ...
[132]
Vertical accretion trends project doughnut-like fragmentation of ...
Feb 9, 2024 · Here we report rates of vertical accretion of 16 new sediment cores collected proximal to platform edges within saltmarshes located behind four barrier islands.<|separator|>
[133]
Most of the World's Salt Marshes Could Succumb to Sea Level Rise ...
Mar 28, 2023 · “Even under conservative sea level estimates…more than 90% of the salt marshes of the world will likely be submerged and disappear or be ...
[134]
Salt marshes and sea level rise - Woodwell Climate
Feb 28, 2023 · Salt marshes, important for storing carbon, housing wildlife, and buffering storm surge, are loosing ground to sea level rise, report finds.
[135]
Vegetation traits and biogeomorphic complexity shape the resilience ...
Nov 4, 2024 · Salt marsh vegetation can have both a direct, local-scale effect of promoting sediment accretion to compensate for sea-level rise (SLR), and an ...
[136]
[PDF] Mosquito Control Impoundments1
The salt marsh mosquitoes Aedes taeniorhynchus and Aedes sollicitans will not lay their eggs upon standing water. Instead, they oviposit upon moist soil; the ...
[137]
Ditching the Salt Marsh Ditches | Delaware Center for the Inland Bays
May 6, 2019 · In addition, the State of Delaware now uses a practice known as “Open Marsh Water Management” to control mosquitoes.
[138]
[PDF] IMPACTS FROM DITCHING SALT MARSHES IN THE MID ...
water management on numbers of larval salt marsh mosquitoes. J. Med ... Relation of mosquito control to bird life of the salt marshes. Proc. N.J. ...
[139]
Salt Marsh Ditches of the South Shore - Part 2
Nov 4, 2022 · Salt marsh ditches were dug to control mosquitoes, using grid-ditching to remove standing water, and later, by removing obstacles to allow ...
[140]
[PDF] NJDEP-Office of Mosquito Control-Open Marsh Water Management ...
OMWM is a land management practice that restores salt marsh habitat that has been disturbed by human intervention through practices such as parallel grid ...
[141]
The evolution of saltmarsh mosquito control water management ...
Aug 13, 2021 · IMM not only uses OMWM techniques but incorporates the judicious use of mosquito control pesticides, tidal flow restoration, impoundment ...
[142]
Effects of open marsh water management on numbers of larval salt ...
Open marsh water management (OMWM) is a commonly used approach to manage salt marsh mosquitoes than can obviate the need for pesticide application and at ...Missing: impacts | Show results with:impacts
[143]
The Effect of Open Marsh Water Management Practices on the ...
Here, we assess the impacts of OMWM on the carbon balance of salt marshes associated with the conversion of intact vegetation to open water ponds.
[144]
Responses of salt marsh ecosystems to mosquito control ...
Feb 16, 2011 · Open marsh water management (OMWM) of salt marshes modifies grid-ditched marshes by creating permanent ponds and radial ditches in the high ...
[145]
Environmental and socioeconomic effects of mosquito control in ...
Jul 1, 2020 · Bti has been used in mosquito control programs to reduce nuisance in Europe for decades and is generally considered an environmentally-safe, effective and ...
[146]
A review of current salt marsh management issues in Florida - PubMed
For the past decade, salt marsh management in Florida has been a central issue in attempts to reconcile mosquito control and natural resource interests.Missing: conflicts | Show results with:conflicts
[147]
Florida's salt-marsh management issues: 1991-98 - PubMed
A developing mitigation banking program has the potential to benefit marsh management but mosquito control interests may suffer if not handled properly.Missing: conflicts | Show results with:conflicts
[148]
[PDF] A REVIEW OF CURRENT SALT MARSH MANAGEMENT ISSUES IN ...
ABSTRACT. For the past decade, salt marsh management in Florida has been a central issue in attempts to reconcile mosquito control and natural resource ...Missing: conflicts | Show results with:conflicts
[149]
[PDF] Controlling mosquitoes through innovative and collaborative ...
May 20, 2021 · Historically, ditching to control mosquito populations sought to drain the marsh of pooled waters where mosquito larvae develop and allowed ...
[150]
Salt Marsh Restoration: A Summary of Approaches
Aug 22, 2025 · Ecosystem services performed by coastal wetlands include storm protection, habitat provision, and carbon storage, among others. Because of their ...
[151]
A global meta-analysis on the drivers of salt marsh planting success ...
Apr 29, 2024 · Unsurprisingly, several restoration benefits somewhat slowly developed, and did not achieve equivalence to natural undisturbed marshes even ...
[152]
Economic Evaluation and Systematic Review of Salt Marsh ...
They sustain a rich, dynamic, and productive ecological zone that plays an important role in biological diversity and human welfare (Mitsch and Gosselink, 2015) ...
[153]
A Case Study in Salt Marsh Restoration
Mar 7, 2023 · Since 2020, they have restored surface drainage channels to the marsh, leading to the recovery of acres that had lost vegetation due to rapid ...Missing: studies | Show results with:studies
[154]
A global meta-analysis on the drivers of salt marsh planting success ...
Apr 29, 2024 · Overall, our results suggest that salt marsh planting could be used as a strategy to enhance shoreline protection, biodiversity conservation and ...
[155]
[PDF] Improving Marsh Resilience through the Hurricane Sandy Coastal ...
Sep 13, 2019 · Evaluating salt marsh restoration success with an index of ecosystem integrity. Journal of Coastal Research 29(2):410–418. Tonelli, M., S ...
[156]
Mismatch between watershed effects and local efforts constrains the ...
Apr 10, 2021 · Vegetation community in the Liaohe River Estuary has experienced two dramatic collapses and one recovery periods.
[157]
Resistance, resilience, and recovery of salt marshes in the Florida ...
Oct 14, 2021 · (a) Examples of marsh damage from Hurricane Michael include: (1) deposition of vegetation or sediment, (2) man-made debris, (3) fallen trees, (4) ...
[158]
[PDF] An Overview of Habitat Restoration Successes and Failures in the ...
marsh restoration. ... Given a lack of resources, restoration and maintenance have languished and the site is an example of failed restoration efforts.
[159]
Climate sensitivity and restoration trajectories: Insights from tidal ...
Jul 12, 2025 · We found strong effects of drought on marsh restoration success indicators. Plant colonization rate decreased dramatically over time in the ...
[160]
Case Study: Restoring A Damaged Wetland Preserve
The goal of the project was to restore an area of marsh approximately 175 ft long by 10 ft wide which was damaged during the installation of a boardwalk.
[161]
(PDF) Salt marsh restoration: an overview of techniques and ...
Jan 6, 2022 · This study comprehensively reviewed data from 78 peer-reviewed papers. Results indicated that much of the salt marsh was restored through ...
[162]
Economic Value of Salt Marshes under Uncertainty of Sea Level Rise
Jun 10, 2022 · This study provides the economic value of changes in carbon and non-carbon benefits using predicted changes in salt marsh coverage in Narragansett Bay, Rhode ...
[163]
[PDF] Valuing the Flood Reduction Benefits of Marsh Restoration
Marsh restoration costs are highly variable and project-specific, but for this analysis, we used $80,000 per acre. (in 2021 USD; Bayraktarov et al. 2015), based ...
[164]
The Economic Value of the Saltmarsh Habitat in the UK Using ...
This study presents a comprehensive economic valuation of UK saltmarsh habitats, utilising a benefit transfer approach.2. Literature Review · 2.1. Meta-Regression... · 5. Discussion
[165]
Valuing present and future benefits provided by coastal wetlands ...
In total, these marshes provide $90,144,262/yr across all ecosystem services considered. With a total area (10.7 ha), the restored living shoreline marsh ...
[166]
[PDF] Estimating the Monetary and Nonmonetary Benefits of Salt Marsh in ...
Apr 14, 2025 · Salt marshes are biologically productive ecosystems that offer a variety of valuable resources and ecosystem services to coastal communities ...
[167]
[PDF] Wetlands Program Guidelines on Massachusetts ... - Mass.gov
Dec 3, 2024 · The Office of Coastal Zone Management (CZM) provides a comprehensive review of potential permit requirements, regulatory summaries, and review.
[168]
Nature-Based Solutions: Salt Marsh Habitat Restoration
By 2019, about 60% of the pool had been drained (Pau, 2022). From 2018 to 2021, low marsh grass cover in the pool was reduced by half and was largely replaced ...
[169]
A value based policy approach: The case of an Urban salt marsh ...
Aug 6, 2025 · Salt marsh restoration goals should reflect perceptions and values of residents, especially in areas having high population density. Households ...
[170]
[PDF] Restoration, creation and management of salt marshes and tidal flats
This document is for practitioners and policy planners who are responsible for managing intertidal habitats, especially those that may be responsible for ...
[171]
Method for Saltmarsh Succession - Field Studies Council
The method involves finding a suitable site, using interrupted belt transects, collecting vegetation, slope, and abiotic data, and using quadrats for sampling.Missing: research | Show results with:research
[172]
Where does the salt marsh start? Field-based evidence for the lack ...
Sep 30, 2020 · This study descriptively assesses an array of abiotic and biotic variables that potentially affect successful vegetation establishment.
[173]
Evaluation of Plot-Scale Methods for Assessing and Monitoring Salt ...
The overall goal of this study is to directly compare 3 field sampling methods (point-intercept, Braun–Blanquet visual, and FQA visual) for estimating ...
[174]
[PDF] Kutcher-et-al.-2022-A-rapid-method-to-assess-salt-marsh-condition ...
Apr 7, 2022 · The goal of this paper is to describe and evaluate MarshRAM, focusing on its ability to support salt marsh management. 2. Methods. 2.1. MarshRAM ...
[175]
Modeling Salt Marsh Vegetation Height Using Unoccupied Aircraft ...
Structure-from-Motion (SfM) photogrammetry of the resultant imagery allowed for continuous modeling of the entire marsh ecosystem in a three-dimensional space.<|separator|>
[176]
[PDF] A Strategy for Developing a Salt Marsh Monitoring and Assessment ...
Mar 1, 2016 · This document proposes a three-tiered Salt Marsh Monitoring and Assessment Program (SMMAP) to improve long-term monitoring in Rhode Island.
[177]
Numerical models of salt marsh evolution: Ecological, geomorphic ...
Jan 6, 2012 · We describe in detail models that simulate fluxes of water, organic matter, and sediments in salt marshes. The interplay between biological and ...
[178]
Identifying salt patches and marsh with field data and machine ...
Apr 24, 2025 · Identifying salt patches and marsh with field data and machine-learning algorithm ... Salty soils are causing reduced crop density, lower yields ...
[179]
Numerical modelling of biogeomorphological processes in salt ...
Feb 15, 2025 · This study investigates the importance of spatiotemporally and seasonally varying vegetation dynamics on decadal salt marsh development.
[180]
A Minimalist Model of Salt-Marsh Vegetation Dynamics Driven by ...
We present a new bi-dimensional, spatially explicit ecological model aimed at simulating the dynamics of halophytic vegetation in tidal saline wetlands.
[181]
A Simple Predictive Model for Salt Marsh Internal Deterioration ...
Sep 23, 2025 · Sea-level rise, subsidence, and sediment deficits can lead to submergence, open-water expansion, and ultimately loss of the vegetated marsh ...
[182]
[PDF] Sea level rise in a coastal marsh: linking increasing tidal inundation ...
Jun 26, 2025 · Here, we propose another method between sea level rise, increasing marsh inundation, and decreasing marsh soil strength, that further ...
[183]
Modeling the Dynamics of Salt Marsh Development in Coastal Land ...
Mar 16, 2022 · In this study, a state of the art numerical model was used to simulate marsh development in a typical configuration used in land reclamation projects.
[184]
Early warning signs of salt marsh drowning indicated by widespread ...
Jun 23, 2025 · When we examined patterns over time, we found that most of the Georgia coast S. alterniflora salt marshes (63%) experienced a decrease in BGB ...
[185]
Widespread Expansion of Salt Marsh Pools Observed on Maine ...
Feb 25, 2025 · We found a 15.7% increase in pool area from 2009 to 2021 on all marshes, primarily driven by mega-pool expansion, whereas individual and perimeter pools ...Missing: field | Show results with:field
[186]
Increased sea level rise accelerates carbon sequestration in a ...
Jan 1, 2025 · Faster sea level rise rates enhance salt marsh organic carbon accumulation. Salt marsh levees accumulate organic carbon faster than marsh basins.
[187]
Soil carbon in the world's tidal marshes | Nature Communications
Nov 26, 2024 · Tidal marshes are threatened coastal ecosystems known for their capacity to store large amounts of carbon in their water-logged soils.
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Factors controlling spatiotemporal variability of soil carbon ... - BG
May 16, 2024 · Our results show that soil C varied spatially across a marsh ecosystem by up to 63 % and across plant phenophase by 26 %, causing variability in soil C accrual ...
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https://www.sciencedirect.com/science/article/pii/S0272771425004378
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Large-scale loss of Mediterranean coastal marshes under rising sea ...
Feb 20, 2025 · We predict (near) total loss of coastal marshes by 2100 for current coastal management and sediment supply scenarios.<|control11|><|separator|>