Spartina alterniflora Research Papers - Academia.edu (original) (raw)

2025, Ecology

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2025, Proceedings of the National Academy of Sciences of the United States of America

2025, Biological Conservation

Coastal ecosystems, such as sand dunes, salt marshes, and mangroves, stabilize shorelines and protect coastal populations. In New England, salt marshes have experienced widespread cordgrass (Spartina alterniflora) die-off and habitat loss, and it is unknown how this has affected their ability to provide coastal protection. We quantified wave attenuation and shoreline stability on healthy, die-off and recovered marsh creek banks. We found that coastal protection has been severely compromised by salt marsh die-off, and that to date, S. alterniflora recovery, while superficially impressive, has not returned this ecosystem service to the levels of intact marshes. Climate driven sea-level rise and predicted increases in the frequency and severity of storms over the next century will likely further increase the vulnerability of coastal populations. Therefore, recovery of coastal protection is essential for maintaining the ecological and economic wellbeing of coastal communities. Our results suggest that quantification of the recovery of ecosystem services should be employed in order to successfully measure recovery in degraded ecosystems.

2025, Estuaries and Coasts

To predict the impacts of climate change, a better understanding is needed of the foundation species that build and maintain biogenic ecosystems. Spartina alterniflora Loisel (smooth cordgrass) is the dominant salt marsh-building plant along the US Atlantic coast. It maintains salt marsh elevation relative to sea level by the accumulation of aboveground biomass, which promotes sediment deposition and belowground biomass, which accretes as peat. Peat accumulation is particularly important in elevation maintenance at high latitudes where sediment supply tends to be limited. Latitudinal variation in S. alterniflora growth was quantified in eight salt marshes from Massachusetts to South Carolina. The hypothesis that allocation to aboveground and belowground biomass is phenotypically plastic was tested with transplant experiments among a subset of salt marshes along this gradient. Reciprocal transplants revealed that northern S. alterniflora decreased allocation to belowground biomass when grown in the south. Some northern plants also died when moved south, suggesting that northern S. alterniflora may be stressed by future warming. Southern plants that were moved north showed phenotypic plasticity in biomass allocation, but no mortality. Belowground biomass also decomposed more quickly in southern marshes. Our results suggest that warming will lead northern S. alterniflora to decrease belowground allocation and that belowground biomass will decompose more quickly, thus decreasing peat accumulation. Gradual temperature increases may allow for adaptation and acclimation, but our results suggest that warming will lower the ability of salt marshes to withstand sealevel rise.

2025, Zemdirbyste-Agriculture

Fusarium culmorum (W.G. Smith) is one of the fungal soil-borne plant pathogens causing significant yield and quality losses in cereals. Chemical attempts are not only insufficient for controlling such pathogens, but also they bring hazardous effects on the environment and living organisms. Therefore, environment-friendly plantbeneficial microorganisms including bacteria would replace chemical control agents as promising and sustainable pest management. Numerous studies showed that some strains of plant growth-promoting rhizobacteria comprising the enzyme ACC (1-aminocyclopropane-1-carboxylate)-deaminase could promote the plant growth acting as a biological control agent by lowering the level of excessive ethylene in plants exposed to biotic and abiotic stresses. This study was aimed to evaluate the rhizobacterial isolates obtained from rhizosphere of cereal plants in Konya and Karaman provinces in Turkey for potency of enzyme ACC-deaminase activity and in vitro/in vivo suppression ability on F. culmorum. In total 31 out of 463 rhizobacterial isolates successfully suppressed in vitro growth of F. culmorum on potato dextrose agar following dual-culture technique. Afterwards, the successful isolates were examined for ACC-deaminase activity using ACC as the sole nitrogen (N) source. Two isolates coded as Gu2 and 127b with the highest enzyme ACC-deaminase activity were included in pot trials under controlled conditions for assessing in vivo pathogen suppression ability on wheat seedlings. The in vivo pathogen suppression efficiency of Gu2 and 127b isolates was determined as 81.25% and 37.50%, respectively. It was determined that both rhizobacterial isolates belonged to Bacillus spp. with high reliable score based on MALDI Biotyper System classification results.

2025, Journal of Plant Physiology

A study quantifying the physiological threshhold at which Spartina alterniflora plants are able to tolerate the interactive effects of salinity and soil drying was conducted in a climate controlled greenhouse. The experiment consisted of two levels of salinity (3-5 ppt, L and 35-38 ppt, H) as well as four dynamic water levels: flooding (water level maintained 3-5 cm above the soil surface at high tide and 10 cm below the soil surface at low tide for entire study duration, F), 8-day drought (water level maintained at least 20 cm below the soil surface at high tide for 8 days then flooded, 8 days), 16-day drought (water level maintained at least 20 cm below the soil surface at high tide for 16 days then flooded, 16 days), and 24-day drought (water level maintained at least 20 cm below the soil surface at high tide for 24 days then flooded, 24 days). Plant gas exchange and growth responses were measured along with soil conditions of redox potential and water potential. Significant decreases were seen in plant gas exchange and growth in response to increases in salinity and soil drying. Survival was 100% for all flooded treatments while increased salinity combined with soil drying decreased survival to 86% in both low salt/24-day drought plants (LD24) and high salt/16-day drought plants (HD16). The lowest survival rate was seen in the high salt/24-day drought treatment (HD24) at 29%. Therefore, it appears that the critical time for recovery from the combined effects of increased salinity and soil drying may greatly diminish after two weeks from the onset of stress conditions. Consequently, if salinity continues to increase along the MRDP, marshes dominated by S. alterniflora may be more susceptible to shortterm drought and likewise large-scale marsh browning.

2025, Environmental and Experimental Botany

A study quantifying the role of the interactive effects of salinity and soil drying on nutrient uptake in Spartina alterniflora was conducted in a climate-controlled greenhouse. The experiment consisted of three levels of salinity (3-5 g/L, L; 15-20 g/L, M; 35-38 g/L, H) as well as three dynamic water levels: drought (water level maintained at least 20 cm below the soil surface at high tide, D), intermediate soil drying (water level maintained between 20 cm below the soil surface at low tide and 10 cm below the soil surface at high tide, I), and flooding (water level maintained 3-5 cm above the soil surface at high tide and 10 cm below the soil surface at low tide, F). Survival, shoot and root dry matter production, and concentrations of Al, Ca, Fe, Mg, N, P, K, Na, and S were measured along with soil conditions of redox potential and water potential. Contrary to expectations, the interactive effects of salinity and soil drying were not additive on plant nutrient uptake or biomass. However, both salinity and soil drying significantly impacted root and shoot dry weights. In addition, significant decreases were seen in all nutrients in response to increases in salinity and/or soil drying. High salinity in conjunction with drought (HD) decreased survival to 71%, whereas survival was 100% for all other treatments. Furthermore, leaf chlorosis and browning occurred in plants under increased salinity and drought conditions (HD and MD). Therefore, it appears that drought may magnify the adverse effects of salinity on plant nutrient status. Although the combined effects of increased salinity and soil drying did not appear to be detrimental to this species, significant decreases in nutrient uptake seen in response to the combined effects at severe levels (HD), if continued over an extended period, may be detrimental enough to cause large-scale marsh browning as noted in the field.

2025, Plant Science

Non-heading Chinese cabbage (Brassica rapa ssp. chinensis) is one of the main green leafy vegetables in the world, especially in China, with significant economic value. Hyaloperonospora parasitica is a fungal pathogen responsible for causing downy mildew disease in Chinese cabbage, which greatly affects its production. The objective of this study was to identify transcriptionally regulated genes during incompatible interactions between non-heading Chinese cabbage and H. parasitica using complementary DNA-amplified fragment length polymorphism (cDNA-AFLP). We obtained 129 reliable differential transcript-derived fragments (TDFs) in a resistant line 'Suzhou Qing'. Among them, 121 upregulated TDFs displayed an expression peak at 24-48 h post inoculation (h.p.i.). Fifteen genes were further selected for validation of cDNA-AFLP expression patterns using quantitative reverse transcription PCR. Results confirmed the altered expression patterns of 13 genes (86.7%) revealed by the cDNA-AFLP. We identified four TDFs related to fungal resistance among the 15 TDFs. Furthermore, comparative analysis of four TDFs between resistant line 'Suzhou Qing' and susceptible line 'Aijiao Huang' showed that transcript levels of TDF14 (BcLIK1_A01) peaked at 48 h.p.i. and 25.1-fold increased in the resistant line compared with the susceptible line. Similarly, transcript levels of the other three genes, TDF42 (BcCAT3_A07), TDF75 (BcAAE3_A06) and TDF88 (BcAMT2_A05) peaked at 24, 48 and 24 h.p.i. with 25.1-, 100-and 15.8-fold increases, respectively. The results suggested that the resistance genes tended to transcribe at higher levels in the resistance line than in the susceptible line, which may provide resistance against pathogen infections. The present study might facilitate elucidating the molecular basis of the infection process and identifying candidate genes for resistance improvement of susceptible cultivars.

2025, Journal of Aquatic Plant …

Smooth cordgrass ( Spartina alterniflora Loisel.) is the single most important grass species in salt marshes along the Gulf of Mexico and the eastern United States coastline. In spring 2000, coastal Louisiana experienced rapid and large scale damage to its salt marshes due to a brown marsh event. We analyzed the genetic relationship among the S. alterniflora samples collected from the severely affected dead zones and lightly affected peripheral transition zones of brown marshes and compared it with those from healthy marsh areas. Forty S. alterniflora individuals collected from 18 brown marsh and 6 healthy non-brown marsh sites were fingerprinted using amplified fragment length polymorphism (AFLP) markers. Twelve Eco RI/ Mse I primer combinations produced 684 scoreable fragments, of which 59.9% were polymorphic. Each S. alterniflora individual was clearly distinguished by its unique AFLP fingerprint. Individuals from healthy marshes were clearly separated from individuals of brown marsh-affected areas in UPGMA cluster analysis. Individuals in closer proximity to each other tend to be more genetically related than those sampled in distantly located sites. Partitioning of the genetic variability by analysis of molecular variance (AMOVA) showed that the within-group variance component was high (91%) compared to the between-group component (9%). This preliminary study suggests that the surviving brown marsh individuals are genetically different from those of healthy marshes, and their survival could be due to favorable combination of genes responsible for tolerance to multiple abiotic stresses. However, further confirmation by DNA assay and field evaluation using large sample size is necessary to identify die-back tolerant genotypes for marsh restoration projects.

2025

Random amplified polymorphic DNA (RAPD) markers were initially used to gain provisional insight into the genetic variation among and within population of Spartina and their hybrids (Ayres et al., 1999). In contrast to simple sequence repeat (SSR) markers, RAPD does not involve high costs of time and money. The arbitrary decamer primer amplifies a set of unknown genomic sequences, which are run on an agarose gel and which can be scored as present or absent. However, a highly controlled and monitored setting is necessary to ensure its reproducibility (Ellsworth et al., 1993; Pan et al., 1997; Riedy et al., 1992; Scot et al., 1993). The ISP found that the variation in results between laboratories (University of

2025

In this study, heavy metals concentration of arsenic, mercury, zinc, and copper were measured and studied in four native species of Dezful’s aquatic plants includes of efficient Chara sp., Reed Phragmites australis, Typha latifolia and Scirpus bulrush in spring of 2014. After sampling from south of Dez river, samples weretransported to the laboratory and dried by autoclave in standard methods. Heavy metals have been measured in root, leaf and stem by atomic absorption. The results presentthat root of aquatic plantshas the most accumulation of heavy metals. Zinc was the highest amount in aquatic plant. Typha latifolia showed the most zinc in this study. Keyword: arsenic, mercury, zinc, copper, Chara sp., Phragmites australis, Typha latifolia, Scirpus bulrush Mansoreh Ghaeni1* Laleh Roomiani2 Laila Safarkhanlo3 1, 2. Department of Fisheries, Agriculture Faculty, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran. 3. Ph.D. of Fisheries, Tehran, Iran *Corresponding author mansoreh.ghaen...

2025

Geese are large, herbivorous birds that graze in huge flocks in ways that may have a considerable impact on vegetation. This is exemplified best in two subspecies of snow geese, the lesser and the greater, both of which have increased dramatically in numbers in recent decades. In arctic coastal salt marshes, moderate goose grazing on Puccinellia phryganodes enhances plant production, but if it intensifies beyond a certain threshold it destroys the plant cover, leading to hypersalinity, soil erosion and little revegetation for long periods. In freshwater tundra wetlands dominated by Dupontia fisheri, Eriophorum scheuchzeri and brown mosses, grazing changes plant composition and reduces production of Eriophorum. Grazing may also favor mosses at the expense of grasses and sedges because mosses short-stop most of the nitrogen released from goose faeces. In temperate salt marshes, damage to the binding plant Spartina alterniflora from goose grubbing has been locally severe and has led to the devegetation of large areas. In temperate brackish marshes, geese heavily grub the rhizomes of Scirpus pungens. Their grubbing depresses Scirpus production, alters plant species composition, and influences marsh dynamics by enlarging ice-made depressions which are then colonized by other species. Grazing and grubbing in arctic and temperate freshwater wetlands apparently leads to a low-level production equilibrium between geese and the plants, but not in salt marshes.

2025

This technical report presents the new numerical modeling capabilities for simulating wave attenuation and mean water level changes through flexible vegetation such as smooth cordgrass in coastal and marine wetlands. These capabilities were implemented into the Cross-SHORE (CSHORE) numerical model. The biomechanical properties of vegetation such as dimensions, flexibility, and bending strength are parameterized in terms of the scaling law. Correspondingly, a new formulation of the vegetation drag coefficient, CD, is developed using field data from a salt marsh in Terrebonne Bay, LA, by considering spatially varying effective stem and blade heights of species. This report also presents a general procedure for using the model to simulate hydrodynamic variables (i.e., waves, currents, mean water levels) at vegetated coasts, which are used to quantify the effects of wave attenuation and reduction of surge and runup due to vegetation. Preliminary model validation was conducted by simulat...

2025, Marine Ecology Progress Series

Some studies have shown that the balance between top-down and bottom-up processes is context dependent, but few have tested how biotic interactions can affect this balance. We quantified the attack frequencies by the stem borer moth Haimbachia sp. nov. on the cordgrasses Spartina densiflora and S. alterniflora in 5 marshes of the southwestern Atlantic coastline, located between 36°S and 41°S. We examined whether ecosystem engineering by burrowing crabs Neohelice (Chasmagnathus) granulata, which improves plant performance, increases herbivory incidence by moths. The results show that moths attack an important proportion of Spartina spp. stems (4% to 26%). Moth attack frequencies were higher on low elevation than on high elevation marsh plants, probably due to variations in plant performance across the physical stress gradient. Within marshes, burrowing crab densities and moth attack frequencies were positively correlated, suggesting that ecosystem engineering by crabs may increase moth attacks. Field experiments confirmed this prediction and suggest that the effect of crabs on moth attacks may be driven by nutrient availability. Our results show that stem-boring herbivores can cause significant plant mortality in Spartina spp. marshes, and that ecosystem engineering by burrowing crabs increases this effect. Thus, in this system, biotic factors that improve plant performance lead to an increase in herbivory control.

2025, Journal of Experimental Marine Biology and Ecology

The role of positive interactions is often crucial in communities with intense abiotic stress such as intertidal environments. Grasses acting as ecosystem engineers, for example, may ameliorate intertidal harsh physical conditions and modify the community structure. The mud snails Heleobia australis d'Orbigny frequently inhabit the SW Atlantic marshes, mainly associated to intertidal marsh plants (mainly the smooth cordgrass Spartina alterniflora Loisel) probably due to the plant indirect effects. The purpose of this work was to investigate the magnitude of these association and the processes that generate the pattern. Samples of the snail abundance in six SW Atlantic coastal marshes show that H. australis is associated to coastal areas of low energy and low or none freshwater input. This result is important because this species is being used as bioindicator of coastal estuarine systems during the Holocene. Thus the paleontological interpretation based on this species should be revised. Within the studied areas, snails are associated to intertidal marsh plants. However, stable isotope analysis shows that neither plant nor their epiphytes are their main food sources. Field experiments show that snails actively select areas with plants, although tethering experiments show that plants do not provide shelter from predators. However, plants do buffer physical stress factors such as temperature, which generate important mortality outside plants covered areas. These positive interactions have large effects on H. australis distributions in marsh communities; increasing the habitats available for colonization and affecting their local distribution.

2025, Soil Ecology Letters

• Silt+clay was the dominant soil aggregate fraction in coastal wetlands. • The invasion of mudflats by Spartina increased macroaggregate fraction and associated carbon. • Aquaculture reclamation reduced aggregate size and stability. • Macro-and micro-aggregates were important for soil carbon storage. Soil aggregates are essential to the long-term sequestration of soil organic carbon (SOC) in coastal wetlands. Coastal wetlands in China have undergone profound transformation by the invasion of Spartina alterniflora and subsequent aquaculture reclamation, but the effects on soil aggregates remain unclear. This study examined the distribution of soil aggregate size, stability and organic carbon content across 21 coastal wetlands in China that had undergone a similar transformation, from native mudflats (MFs) to S. alterniflora marshes (SAs), and subsequent conversion to aquaculture ponds (APs). The results showed that silt+clay was the dominant fraction of soil aggregates (78.7%-83.1%), followed by micro-aggregates (12.8%-13.9%) and macroaggregates (4.1%-6.6%). Transition from MFs to SAs led to an increase in macroaggregate and microaggregate contents and the aggregate stability index (MWD, MGD and DR 0.25), but a reduction in silt+clay content. Subsequent conversion of SAs to APs led to a reduction in macroaggregate content and aggregate stability index, and an increase in silt+clay and microaggregate contents. Change from MFs to SAs increased SOC by 69.6% in the silt+clay fraction, 29.4% in the microaggregate fraction, and 22.4% in the macroaggregate fraction. Conversely, converting SAs to APs decreased SOC content by 11.4% in the silt+clay fraction and 16.3% in the macroaggregate fractions, but an 8.5% increase in the microaggregate fraction. The results underscore the crucial role of soil aggregate formation in sequestration and storage of SOC under varying land cover change scenarios.

2025, Ecological Applications

The rapid decline in the extent and health of coastal salt marshes has created a need for nondestructive methods for evaluating the condition of salt marsh ecosystems. This paper describes simultaneous uses of field sampling and remote sensing approaches to understand salt marsh ecosystem functions and species distributions and discusses the implications for salt marsh monitoring using remote sensing. Three sites along the Petaluma River near the entrance into San Pablo Bay, California, which represented a range of soil salinity, water content, and nutrients, were studied. Standing biomass was directly assessed by field sampling and indirectly estimated through canopy reflectance. The sites were dominated by almost monotypic stands of Salicornia virginica, Spartina foliosa, and Scirpus robustus. For Salicornia, we found a positive relationship between salinity and biomass up to a threshold of 42 g/kg, after which biomass declined monotonically with increasing salinity. No Scirpus or Spartina were found at soil salinities Ͼ20 g/kg. Although significantly different levels of nitrate and ammonium nitrogen were found in the interstitial water and soils at these sites, no strong relationships were found between biomass and nitrate nitrogen. Soil ammonium nitrogen, in contrast, was positively related to biomass. Soil redox and salinity increased with elevation and distance from the shoreline, while soil moisture and H 2 S decreased. Canopy biomass was estimable using remotely sensed spectral vegetation indices at 58-80% accuracy depending on species. Simple Vegetation Index (VI) and Atmospherically Resistant Vegetation Index (ARVI) measured by handheld field spectrometers were the best estimators of green biomass for high cover of Salicornia. Soil Adjusted Vegetation Index (SAVI) and Soil Adjusted and Atmospherically Resistant Vegetation Index (SARVI) gave the best estimates for Spartina while the Global Environment Monitoring Index (GEMI) was the best estimate for Scirpus. The relationships between vegetation indices and biomass were developed from field spectra. The VI was used to estimate spatial patterns of biomass across the salt marsh from Landsat satellite Thematic Mapper (TM) data. The TM image showed spatial patterns corresponding with species zones and biomass abundance. Narrow band reflectance features measured with a handheld spectrometer can be used to predict canopy plant water content (R 2 ϭ 63%). Interpolated estimates of water content from field-measured canopy reflectance were shown to relate to variation in salinity and soil moisture. Canopy water content was estimated from Airborne Advanced Visible Infrared Imaging Spectrometer data, which showed similar spatial patterns at the site. Results indicate that both biomass production and canopy water content can be accurately determined from remotely sensed spectral measures. Species-specific differences in these characteristics may be used for monitoring species distribution and abundance from airborne or satellite images.

2025, Marine Biology

Benthic particle feeders are exposed to a food supply varying in both quantity and quality. Previous studies have shown that bivalve molluscs deal with such ¯uctuating particle regimes in a variety of ways, including adjustments in pumping and ingestion rates, and selective rejection of non-nutritive particles as pseudofeces. The actual site of particle selection within the pallial cavity, however, has remained a topic of speculation. During August 1995 and January and August 1996, we exposed the oysters Crassostrea virginica (Gmelin) and C. gigas (Thunberg), and the mussel Mytilus trossulus Gould to a mixture of ground, aged Spartina alterni¯ora Loisel and similar-sized phytoplankton at three concentrations (10 3 , 10 4 , 10 5 particles ml A1 ). We then examined the ctenidia and labial palps by means of endoscopy and sampled, in vivo, the particulate material from various ciliated tracts, and analyzed the samples with a ¯ow cytometer. We found that in oysters, the ctenidia are responsible for particle sorting, whereas the labial palps play an accessory role in particle selection, or function to control the volume of material to be ingested. In mussels, however, the ctenidia play little role in particle selection and simply transport particulate matter to the palps for further processing. We suggest that selection by the ctenidia of oysters is a function of their architecture (plicate, heterorhabdic).

2025, Estuaries

Packets of freshly harvested live Spartina alterniflora were placed on the marsh surface, in a tidal ditch, in a pool contacting sides and bottom, and in the center-bottom of the same pool in September 1972. Rates of loss were the same for all four sites through day 242. After that packets on the marsh surface decomposed slower. A second experiment was begun in July only at the marsh surface and pool side sites. These lost dry weight much more rapidly than packets started in September. Populations of bacteria, fungi, diatoms, flagellates, ciliates and nematodes within the packets peaked within 60 days then decreased proportionately with the loss of dry weight in packets through day 242. After this, bacterial numbers decreased more rapidly presumably in response to a qualitative change in the packet material. Populations of flagellates and ciliates also declined rapidly after day 300. This decline occurred in new packets at around this date as well. In a limited set of samples 12 taxa were analyzed for date or detritus-age dependent occurrence. Of these, eight were date dependent, two were dependent on packet age, and two could not be determined from the data.

2025

Spartina alterniflora (Loisel.), smooth cordgrass, is a dominant perennial salt marshgrass native to tidal wetland plant communities along the Atlantic and Gulf coasts of North America. It is an important plant species for coastal reclamation and restoration efforts. It spreads quickly by rhizomes and tolerates a wide range of saline, anoxic, and sulfidic soils. However, because of poor seed production this species is propagated vegetatively for reclamation or restoration projects. Current practices reduce genetic diversity of the species by utilizing a single vegetatively propagated genotype. The objectives of this study were; 1) identify multiple genotypes of S. alterniflora for use in restoration efforts and 2) assess genetic variability of these genotypes at the molecular level. Identification of desirable plants was based on plant growth characteristics and reproductive traits. Growth characters were plant height, spread, rust reaction, and vigor. Reproductive traits were seed set, germination, kernel weight, seed weight, and total seed per plant. This process resulted in seven plants, descended from seven different original source populations, which demonstrated superior performance for vegetative and reproductive traits. Molecular marker analysis revealed that genetic diversity, essential for success in the restoration projects, was maintained in selected plants. These plants offer an enhanced germplasm base for current restoration efforts. Research is continuing on the feasibility of developing seed based populations that would add even greater genetic diversity to the current accepted restoration practices.

2025, Evolutionary Applications

Ecosystem engineers that modify landforms can be valuable tools for restoring habitat, but their use has frequently resulted in unanticipated outcomes. Departures from expectations might arise because applications discount the possibility that geomorphic processes are influenced by heritable phenotypic variation. We conducted a field‐scale common garden experiment to assess whether shoreline erosion reflects intraspecific variation in the landform engineer Spartina alterniflora. Replicated plots on a shoreline denuded by the Deepwater Horizon oil spill were revegetated using plants from four genetically distinct sources: the local population, a nonlocal population, and two nursery stocks. We assessed variation in biomass, tissue nutrients, and functional traits alongside soil shear strength, surface elevation, and shoreline erosion rates over 2 years. We found that productivity, traits, nutrient content, and erosion rates varied according to plant provenance. Erosion reflected trait...

2025, American Journal of Botany

PremiseThere is growing recognition that intraspecific genetic variation in plants can influence associated soil microbial communities, but the functional bridges linking plant genotype with microbial community structure are not well understood. This deficit is due in part to a prevailing focus on characterizing relationships between microbial communities and functional trait variation among plant species or across plant communities, rather than within a single species.MethodsWe examined whether and how spatiotemporal variation in salt marsh rhizosphere microbial communities reflect plant provenance (genotypic variation) and associated trait variation within an ecosystem engineer, Spartina alterniflora. We planted S. alterniflora from four genetically distinct source populations in replicate sets of experimental plots across a shoreline in southeastern Louisiana, USA. After 2 years, we measured functional plant traits and profiled microbial communities.ResultsBacterial and fungal α‐...

2025, Basavaraj I Hubli

Remote sensing has emerged as an invaluable tool for monitoring groundwater quality, offering a non-invasive, cost-effective method for tracking surface-level changes and indirectly identifying potential contamination sources. This paper explores the role of remote sensing in groundwater quality monitoring, including its various platforms, sensors, and techniques. We also discuss the applications, challenges, and future directions of this field.

2025

El conocimiento oportuno y sistematico del ciclo del carbono (flujos y reservorios) en los mares y costas mexicanas, aportara elementos para definir las estrategias y politicas publicas relacionadas con la mitigacion y adaptacion ante los impactos del cambio climatico, como por ejemplo, la elevacion del nivel del mar, la migracion y/o perdida de especies marinas de interes comercial, los impactos en los procesos biogeoquimicos (acidificacion e hipoxia) y su influencia en las actividades pesqueras, acuaculturales y turisticas de la region, asi como las consecuencias socioeconomicas en las diversas actividades que se desarrollan en las zonas costeras. Sin duda, una de las acciones fundamentales del Programa Mexicano del Carbono debe ser promover entre las instituciones gubernamentales, academicas y los tomadores de decision, el compromiso de apoyar los distintos programas de monitoreo en varias escalas (espacio-temporales) a mediano y largo plazo, de los procesos y variables relaciona...

2025, Ecology

In 2014 a DNA-based phylogenetic study confirming the paraphyly of the grass subtribe Sporobolinae proposed the creation of a large monophyletic genus Sporobolus, including (among others) species previously included in the genera Spartina, Calamovilfa, and Sporobolus. Spartina species have contributed substantially (and continue contributing) to our knowledge in multiple disciplines, including ecology, evolutionary biology, molecular biology, biogeography, experimental ecology, biological invasions, environmental management, restoration ecology, history, economics, and sociology. There is no rationale so compelling to subsume the name Spartina as a subgenus that could rival the striking, global iconic history and use of the name Spartina for over 200 years. We do not agree with the subjective arguments underlying the proposal to change Spartina to Sporobolus. We understand the importance of both the objective phylogenetic insights and of the subjective formalized nomenclature and hope that by opening this debate we will encourage positive feedback that will strengthen taxonomic decisions with an interdisciplinary perspective. We consider that the strongly distinct, monophyletic clade Spartina should simply and efficiently be treated as the genus Spartina.

2025, Remote Sensing

Airborne lidar can observe saltmarshes on a regional scale, targeting phenological and tidal states to provide the information to more effectively utilize frequent multispectral satellite observations to monitor change. Airborne lidar observations from NASA Goddard Lidar Hyperspectral and Thermal (G-LiHT) of a well-studied region of saltmarsh (Plum Island, Massachusetts, United States) were acquired in multiple years (2014, 2015 and 2016). These airborne lidar data provide characterizations of important saltmarsh components, as well as specifications for effective surveys. The invasive Phragmites australis was observed to increase in extent from 8374 m2 in 2014, to 8882 m2 in 2015 (+6.1%), and again to 13,819 m2 in 2016 (+55.6%). Validation with terrestrial lidar supported this increase, but suggested the total extent was still underestimated. Estimates of Spartina alterniflora extent from airborne lidar were within 7% of those from terrestrial lidar, but overestimation of height of...

2025, Estuaries and Coasts

2025, Ecological Applications

In saltmarsh plant communities, bottom‐up pressure from nutrient enrichment is predicted to increase productivity, alter community structure, decrease biodiversity, and alter ecosystem functioning. Previous work supporting these predictions has been based largely on short‐term, plot‐level (e.g., 1–300 m2) studies, which may miss landscape‐level phenomena that drive ecosystem‐level responses. We implemented an ecosystem‐scale, nine‐year nutrient experiment to examine how saltmarsh plants respond to simulated conditions of coastal eutrophication. Our study differed from previous saltmarsh enrichment studies in that we applied realistic concentrations of nitrate (70–100 μM NO3−), the most common form of coastal nutrient enrichment, via tidal water at the ecosystem scale (~60,000 m2 creeksheds). Our enrichments added a total of 1,700 kg N·creek−1·yr−1, which increased N loading 10‐fold vs. reference creeks (low‐marsh, 171 g N·m−2·yr−1; high‐marsh, 19 g N·m−2·yr−1). Nutrients increased t...

2025, American Journal of Botany

On the U.S. Atlantic coast, Spartina alternifl ora Loisel (smooth cordgrass) is the species responsible for initial salt marsh colonization and the ongoing maintenance of the seaward edge of established salt marshes ( Redfi eld, 1972 ;. Like many aquatic plants, S. alternifl ora reproduces both through water-dispersed seeds and clonally via belowground rhizomes. It has generally

2025, Wetlands Ecology and Management

The haying of salt marshes, a traditional activity since colonial times in New England, still occurs in about 400 ha of marsh in the Plum Island Sound estuary in northeastern Massachusetts. We took advantage of this haying activity to investigate how the periodic large-scale removal of aboveground biomass affects a number of marsh processes. Hayed marshes were no different from adjacent reference marshes in plant species density (species per area) and end-of-year aboveground biomass, but did differ in vegetation composition. Spartina patens was more abundant in hayed marshes than S. alterniflora, and the reverse was true in reference marshes. The differences in relative covers of these plant species were not associated with any differences between hayed and reference marshes in the elevations of the marsh platform. Instead it suggested that S. patens was more tolerant of haying than S. alterniflora. S. patens had higher stem densities in hayed marshes than it did in reference marshes, suggesting that periodic cutting stimulated tillering of this species. Although we predicted that haying would stimulate benthic chlorophyll production by opening up the canopy, we found differences to be inconsistent, possibly due to the relatively rapid regrowth of S. patens and to grazing by invertebrates on the algae. The pulmonate snail, Melampus bidendatus was depleted in its  13 C content in the hayed marsh compared to the reference, suggesting a diet shift to benthic algae in hayed marshes. The stable isotope ratios of a number of other consumer species were not affected by haying activity. Migratory shorebirds cue in to recently hayed marshes and may contribute to short term declines in some invertebrate species, however the number of taxa per unit area of marsh surface invertebrates and their overall abundances were unaffected by haying over the long term. Haying had no impact on nutrient concentrations in creeks just downstream from hayed plots, but the sediments of hayed marshes were lower in total N and P compared to references. In sum, haying appeared to affect plant species composition but had only short-term affects on consumer organisms. This contrasts with many grassland ecosystems, where an intermediate level of disturbance, such as by grazing, increases species diversity and may stimulate productivity. From a management perspective, periodic mowing could be a way to maintain S. patens habitats and the suite of species with which they are associated.

2025, Marine Ecology Progress Series

2025, Journal of Experimental Marine Biology and Ecology

Responses of infaunal saltmarsh benthic invertebrates to whole-ecosystem fertilization and predator removal were quantified in Plum Island Estuary, Massachusetts, USA. Throughout a growing season, we enriched an experimental creek on each flooding tide to 70 µM NO 3 -and 4 µM PO 4 -3 (a 10 x increase in loading above background), and we reduced Fundulus heteroclitus density by 60% in a branch of the fertilized and a reference creek. Macroinfauna and meiofauna were sampled in creek (mudflat and creek wall), marsh edge (tall form Spartina alterniflora) and marsh platform (Spartina patens and stunted S. alterniflora) habitats before and after treatments were begun; responses were tested with BACI-design statistics. Treatment effects were most common in the mid-range of the inundation gradient. Most fertilization effects were on creek wall where ostracod abundance increased, indices of copepod reproduction increased and copepod and annelid communities were altered. These taxa may use epiphytes (that respond rapidly to fertilization) of filamentous algae as a food source. Killifish reduction effects on meiobenthic copepod abundance were detected at the marsh edge and suggest predator limitation. Fish reduction effects on annelids did not suggest top-down regulation in any habitat; however, fish reduction may have stimulated an increased predation rate on annelids by grass shrimp. Interactions between fertilization and fish reduction occurred under S. patens canopy where indirect predator reduction effects on annelids were indicated. No effects were observed in mudflat or stunted S. alterniflora habitats. Although the responses of infauna to fertilization and predator removal were largely independent and of similar mild intensity, our data suggests that the effects of ecological stressors vary across the marsh landscape.

2025, Ecological Applications

Salt marsh ecosystems have been considered not susceptible to nitrogen overloading because early studies suggested that salt marshes adsorbed excess nutrients in plant growth. However, the possible effect of nutrient loading on species composition, and the combined effects of nutrients and altered species composition on structure and function, was largely ignored. Failure to understand interactions between nutrient loading and species composition may lead to severe underestimates of the impacts of stresses. We altered whole salt marsh ecosystems (;60 000 m 2 /treatment) by addition of nutrients in flooding waters and by reduction of a key predatory fish, the mummichog. We added nutrients (N and P; 15-fold increase over ambient conditions) directly to the flooding tide to mimic the way anthropogenic nutrients are delivered to marsh ecosystems. Despite the high concentrations (70 mmol N/L) achieved in the water column, our annual N loadings (15-60 g NÁm À2 Áyr À1 ) were an order of magnitude less than most plot-level fertilization experiments, yet we detected responses at several trophic levels. Preliminary calculations suggest that 30-40% of the added N was removed by the marsh during each tidal cycle. Creek bank Spartina alterniflora and high marsh S. patens production increased, but not stunted high marsh S. alterniflora. Microbial production increased in the fertilized creek bank S. alterniflora habitat where benthic microalgae also increased. We found top-down control of benthic microalgae by killifish, but only under nutrient addition and in the opposite direction (increase) than that predicted by a fish-invertebrate-microalgae trophic cascade. Surprisingly, infauna declined in abundance during the first season of fertilization and with fish removal. Our results demonstrate ecological effects of both nutrient addition and mummichog reduction at the whole-system level, including evidence for synergistic interactions.

2025, Plant and Soil

The effects of salt stress on the salt marsh halophyte Spartina alterniflora have been well documented. However, plant responses to combined salinity and ammonium toxicity and the underlying mechanisms are relatively unknown. The aim of the present investigation was to study the effects of both salinity (0, 200 and 500 mM NaCl) and nitrogen form (NO 3 -, NH 4 + or NH 4 NO 3 ) on S. alterniflora. Methods Plants were cultivated in sandy soil under greenhouse conditions for 3 months. At harvest, growth parameters were measured and leaf samples were analysed for oxidative stress parameters (malondialdehyde, MDA; electrolyte leakage, EL; and hydrogen peroxide, H 2 O 2 concentration) and the activity of antioxidant enzymes (glutathione reductase, GR; superoxide dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX and Guaiacol peroxidase, GPX). Results In the absence of NaCl, plant growth rate was the highest in the medium containing both nitrogen forms, and the lowest in the medium containing only nitrate. Irrespective of the nitrogen form, plant growth was generally higher at 200 mM NaCl than without salinity. Ammonium-fed plants showed better growth than nitrate-fed plants under high salinity. In the absence of salinity, ammonium-fed plants showed higher SOD, APX, GR, CAT, and GPX activities than nitratefed ones. The antioxidant enzymes exhibited higher activity in saline-treated plants. The considerable advantage of NH 4 + nutrition to S. alterniflora under saline conditions was associated with high antioxidant enzyme activities, together with low MDA content, EL, and H 2 O 2 concentration. Conclusion These data clearly demonstrate that NH 4 + is more favourable for the growth of S. alterniflora under high salinity than NO 3 -. It is suggested that NH 4 + nutrition improves the plant's capacity to limit oxidative damage by stimulating the activities of the major antioxidant enzymes.

2025, Global change biology

Coastal salt marshes are sensitive to global climate change and may play an important role in mitigating global warming. To evaluate the impacts of Spartina alterniflora invasion on global warming potential (GWP) in Chinese coastal areas, we measured CH4 and N2 O fluxes and soil organic carbon sequestration rates along a transect of coastal wetlands in Jiangsu province, China, including open water; bare tidal flat; and invasive S. alterniflora, native Suaeda salsa, and Phragmites australis marshes. Annual CH4 emissions were estimated as 2.81, 4.16, 4.88, 10.79, and 16.98 kg CH4 ha(-1) for open water, bare tidal flat, and P. australis, S. salsa, and S. alterniflora marshes, respectively, indicating that S. alterniflora invasion increased CH4 emissions by 57-505%. In contrast, negative N2 O fluxes were found to be significantly and negatively correlated (P < 0.001) with net ecosystem CO2 exchange during the growing season in S. alterniflora and P. australis marshes. Annual N2 O em...

2025, Journal of Experimental Marine Biology and Ecology

The roles of recruitment variability an d adult conspecifics on th e di st ribution of Gewkensia demissa (Dillwyn) in a Spa,fina affemijlora ( Loisel) marsh were examined in a field swdy. Rccruilmen! to ex perimental collectors was compared 10 recrui tment onto the marsh su rface at th ree shore levels_ Peak recruitmen t of mussels in the smallest size class (O-5 mm ) occurred in October. Recruitment was greatest o n the marsh edge and to eolleelOrs containing adul t mussels. suggest ing that larval mussels either preferentially sellle or have higher survivorship amo ng adult con specifics. Muss els in the largest size class (5-15 mm) recruited to collectors in early Ju ly suggesting that the previous year's cohor! was still actively involved in post-settlement microhabitat selection.

2025, Marine Ecology Progress Series

Decaying mats of Ulva can be washed into salt marshes by the tides as large wrack deposits, especially in eutrophic estuaries, where they can negatively impact marsh vegetation. Using field and laboratory experiments, we examined the effects of decomposing Ulva on Spartina alterniflora growth, soil biogeochemistry and nitrogen dynamics. High levels of Ulva exposure resulted in reductions in above-and belowground biomass, while lower levels of Ulva exposure resulted in reductions in only belowground biomass. Porewater ammonium in soil that contained decomposing Ulva quickly attained potentially toxic levels. In addition, amending soil with Ulva led to elevated porewater concentrations of sulfide and trithiane, an organosulfur compound and potential biocide. Use of a 15 N tracer documented plant uptake of Ulva-derived nitrogen, but higher nitrogen availability did not stimulate growth. Our findings support the hypothesis that decaying Ulva mats may create hotspots of adverse physiochemical conditions in salt marshes. However, because our Ulva additions were higher than typically found in coastal marshes, additional field and laboratory studies are needed to establish more firmly whether similarly adverse responses are observed under natural conditions.

2025, Journal of Waterway, Port, Coastal, and Ocean Engineering

The impact of sea-level rise on salt marsh sustainability is examined for the lower St. Johns River and associated salt marsh (Spartina alterniflora) system. A two-dimensional hydrodynamic model, forced by tides and sea-level rise, is coupled with a zero-dimensional marsh model to estimate the level of biomass productivity of S. alterniflora across the salt marsh landscape for present day and anticipated future conditions (i.e., when subjected to sea-level rise). The hydrodynamic model results show mean low water (MLW) to be highly spatially variable with a SD of 6 0.18 m and mean high water (MHW) to be less spatially variable with a SD 6 0.03 m. The spatial variability of MLW and MHW is particularly evident within the tidal creeks of the salt marsh. MLW and MHW are sensitive to sea-level rise and respond in a nonlinear fashion (i.e., MLW and MHW elevate by an amount that is not proportional to the level of sea-level rise). The coupled hydrodynamic-marsh model results illustrate the spatial heterogeneity of biomass productivity and indicate marsh vulnerability to sea-level rise. The model is then used to demonstrate an application of engineered accretion that can help sustain a marsh that is exposed to sea-level rise.

2025, Global Change Biology

Marshes worldwide are actively degrading in response to increased sea level rise rates and reduced sediment delivery, though the growth rate of vegetation plays a critical role in determining their stability. We have compiled 56 measurements of aboveground annual productivity for Spartina alterniflora, the dominant macrophyte in North American coastal wetlands. Our compilation indicates a significant latitudinal gradient in productivity, which we interpret to be determined primarily by temperature and/or the length of growing season. Simple linear regression yields a 27 g m−2 yr−1 increase in productivity with an increase of mean annual temperature by 1 °C. If temperatures warm 2–4 °C over the next century, then marsh productivity may increase by 10–40%, though physiological research suggests that increases in the north could potentially be offset by some decreases in the south. This increase in productivity is roughly equivalent to estimates of marsh lost due to future sea level ch...

2025

135 iii 43. Annual variation in Ware Creek marsh high slack water and low slack water phytoplankton productivity 44. Annual variation in Carter Creek marsh high slack water and low slack water phytoplankton productivity 45. Seasonal changes in mean particulate organic carbon (POC) concentrations in Ware Creek and Carter Creek marshes 46. Seasonal changes in mean dissolved organic carbon (DOC) concentration in Ware Creek and Carter Creek marshes 47. Seasonal changes in mean adenosine-tri-phosphate (ATP) concentrations in Ware Creek and Carter Creek marshes 48. Seasonal changes in mean chlorophyll "a" concentrations in Ware Creek and Carter creek marshes 49. Seasonal changes in mean ATP-Carbon values (recorded as percent POC) for Ware Creek and Carter Creek Marshes.

2025

2025, Journal of Applied Remote Sensing

Abstract. As one of the most threatening invasive alien species to mangroves in China, Spartina alterniflora (S. alterniflora) has broadly existed along the Chinese tropical and subtropical coasts. Monitoring S. alterniflora with remote sensing is urgent and requisite for scientific invasive plant control and management. However, given the spectral similarity between S. alterniflora and other wetland types, such as mud covered by algae and the optical image coverage gaps due to cloud and tidal inundation in coastal areas, accurate and timely mapping of S. alterniflora is challenging. Using the extended Jeffries–Matusita distance (JBh), we first explored the best time window for detecting S. alterniflora with satellite data in Zhangjiang Estuary, Fujian, China. Then we presented a hierarchical classification framework to alleviate the spectral confusion problem, combining cost-free Sentinel-1 synthetic aperture radar (SAR) and Sentinel-2 multispectral image time series on the Google ...

2025, Estuarine, Coastal and Shelf Science

Spatial and temporal trends in pore water geochemistry and sediment microbial community structure are compared at three intertidal sites of a saltmarsh on Sapelo Island, GA. The sites include a heavily bioturbated, unvegetated creek bank, a levee with dense growth of Spartina alterniflora, and a more sparsely vegetated ponded marsh site. The redox chemistry of the pore waters ranges from sulfide-dominated at the ponded marsh site to suboxic at the creek bank site. At the three sites, the vertical redox stratification of the pore waters is more compressed in summer than in winter. The trends in redox chemistry reflect opposing effects of sediment respiration and pore water irrigation. Intense and deep burrowing activity by fiddler crabs at the creek bank site results in the efficient oxidation of reduced byproducts of microbial metabolism and, hence, the persistence of suboxic conditions to depths of 50 cm below the sediment surface. Increased supply of labile organic substrates at the vegetated sites promotes microbial degradation processes, leading to sharper redox gradients. At the levee site, this is partly offset by the higher density and deeper penetration of roots and macrofaunal burrows. Surprisingly, the microbial community structure shows little correlation with the variable vertical redox zonation of the pore waters across the saltmarsh. At the three sites, the highest population densities of aerobic microorganisms, iron-plus manganesereducing bacteria, and sulfate reducers coexist within the upper 10 cm of sediment. The absence of a clear vertical separation of these microorganisms is ascribed to the high supply of labile organic matter and intense mixing of the topmost sediment via bioturbation.

2025, Remote Sensing of Environment

We applied a spectroscopic analysis to Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) data collected from low and medium altitudes during and after the Deepwater Horizon oil spill to delineate the distribution of oil-damaged canopies in the marshes of Barataria Bay, Louisiana. Spectral feature analysis compared the AVIRIS data to reference spectra of oiled marsh by using absorption features centered near 1.7 and 2.3 μm, which arise from C\H bonds in oil. AVIRIS-derived maps of oiled shorelines from the individual dates of July 31, September 14, and October 4, 2010, were 89.3%, 89.8%, and 90.6% accurate, respectively. A composite map at 3.5 m grid spacing, accumulated from the three dates, was 93.4% accurate in detecting oiled shorelines. The composite map had 100% accuracy for detecting damaged plant canopy in oiled areas that extended more than 1.2 m into the marsh. Spatial resampling of the AVIRIS data to 30 m reduced the accuracy to 73.6% overall. However, detection accuracy remained high for oiled canopies that extended more than 4 m into the marsh (23 of 28 field reference points with oil were detected). Spectral resampling of the 3.5 m AVIRIS data to Landsat Enhanced Thematic Mapper (ETM) spectral response greatly reduced the detection of oil spectral signatures. With spatial resampling of simulated Landsat ETM data to 30 m, oil signatures were not detected. Overall, ~40 km of coastline, marsh comprised mainly of Spartina alterniflora and Juncus roemerianus, were found to be oiled in narrow zones at the shorelines. Zones of oiled canopies reached on average 11 m into the marsh, with a maximum reach of 21 m. The field and airborne data showed that, in many areas, weathered oil persisted in the marsh from the first field survey, July 10, to the latest airborne survey, October 4, 2010. The results demonstrate the applicability of high spatial resolution imaging spectrometer data to identifying contaminants in the environment for use in evaluating ecosystem disturbance and response.

2025, AGU Fall Meeting Abstracts

of the USGS for their incredible help at Yellowstone and subsequent collaboration, as well as Greg Druschel and Angel Garcia of the University of Vermont and Will Wolfe. Also a huge thank you to Chris Oswalt for constructing Figure , and for so many other things that can't be quantified. Finally, thanks to Phil and the rest of the Bennett Lab for their invaluable assistance and encouragement over the last 3 years.

2025, Frontiers in forests and global change

Globally, mangrove range limits are expanding, often at the cost of adjacent coastal ecosystems including saltmarshes, potentially leading to a change in ecosystem services such as organic carbon (OC) sequestration. Studies in the southeastern US have focused almost exclusively on Avicennia germinans range expansion, the most cold-tolerant mangroves in North America. The Apalachicola Bay region of north Florida represents the northern range limit of mangroves in the Gulf of Mexico, and uniquely also includes Rhizophora mangle. The objective of this research was to quantify soil OC density beneath both mangrove species and compare results to the soils beneath two contiguous native tidal saltmarsh species: Juncus roemerianus and Spartina alterniflora in a barrier island setting. Dominant plant taxa were not a significant predictor of soil OC density, highlighting the relative importance of site-specific environmental attributes as controls on soil properties. Soil profile δ 13 C compositions included a range of values reflective of C 3 and C 4 plant inputs, suggesting that shifts in plant taxa, both from marsh to mangroves and between marsh species, have been occurring at all sites in this study. These findings support much of the literature on mangrove encroachment, which indicates mangrove soil OC concentrations, densities, or stocks are less than or equal to that of co-located tidal marsh habitats. Through a systematic review, the potential of several proposed explanatory variables (climate, environmental setting, plant physiology and productivity, and duration of encroachment) were identified to evaluate how soil OC density in mangrove habitats might increase over time, which is critical to forecasting how continued mangrove expansion might affect blue C storage as these habitats evolve.

2025, Ecological Applications

In recent decades the grass Phragmites australis has been aggressively invading coastal, tidal marshes of North America, and in many areas it is now considered a nuisance species. While P. australis has historically been restricted to the relatively benign upper border of brackish and salt marshes, it has been expanding seaward into more physiologically stressful regions. Here we test a leading hypothesis that the spread of P. australis is due to anthropogenic modification of coastal marshes. We did a field experiment along natural borders between stands of P. australis and the other dominant grasses and rushes (i.e., matrix vegetation) in a brackish marsh in Rhode Island, USA. We applied a pulse disturbance in one year by removing or not removing neighboring matrix vegetation and adding three levels of nutrients (specifically nitrogen) in a factorial design, and then we monitored the aboveground performance of P. australis and the matrix vegetation. Both disturbances increased the density, height, and biomass of shoots of P. australis, and the effects of fertilization were more pronounced where matrix vegetation was removed. Clearing competing matrix vegetation also increased the distance that shoots expanded and their reproductive output, both indicators of the potential for P. australis to spread within and among local marshes. In contrast, the biomass of the matrix vegetation decreased with increasing severity of disturbance. Disturbance increased the total aboveground production of plants in the marsh as matrix vegetation was displaced by P. australis. A greenhouse experiment showed that, with increasing nutrient levels, P. australis allocates proportionally more of its biomass to aboveground structures used for spread than to belowground structures used for nutrient acquisition. Therefore, disturbances that enrich nutrients or remove competitors promote the spread of P. australis by reducing belowground competition for nutrients between P. australis and the matrix vegetation, thus allowing P. australis, the largest plant in the marsh, to expand and displace the matrix vegetation. Reducing nutrient load and maintaining buffers of matrix vegetation along the terrestrial-marsh ecotone will, therefore, be important methods of control for this nuisance species.