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Germination and especially emergence can decrease significantly with depth. Our main goal was to examine the effects of sand burial depth on seed germination and seedling establishment of two halop...

Cordgrasses usually are dominant species in salt marshes all around the world and they play very important roles in ecosystem functioning. Cordgrass biomass accumulation below and above the sediment surface determines energy and material flows in salt marshes. Most cordgrasses show markedly spatial variations in their biomass accumulation pattern, depending on biotic and abiotic environmental factors and on their growth form (“guerrilla” versus “phalanx”, and “short” versus “tall” form). Thus, specific studies to evaluate the ecological roles of cordgrasses should be carried out for each specific location and for each taxon, analyzing both below- and above-ground biomass production and accumulation. In this context, it is very important to choose an appropriate sampling method adapted to our own goals and that would allow comparisons with previous studies. Future research is needed specially to improve our knowledge about cordgrass belowground biomass accumulation, dynamic and functions. The evaluation of the salt marsh ecosystem will be incomplete if based exclusively on what is happening aboveground, or as though what happens aboveground is a satisfactory indicator of what is driving changes belowground. Monitoring programs, for example, could be improved if belowground soil processes were included, rather than excluded, as happens frequently. Furthermore, it may be that because of the dominance of the changes in biomass pools belowground compared to aboveground, what happens belowground may be more influential to the long-term maintenance of the salt marsh than are changes in the aboveground components.

Some introduced species spread rapidly beyond their native range and into novel habitats mediated by a high degree of phenotypic plasticity and/or rapid evolutionary responses. In this context, clonality has been described as a significant factor contributing to invasiveness. We studied the abiotic environment and the responses of different tussock architecture traits of the invasive cordgrass Spartina densiflora Brongn. (Poaceae). A common garden experiment and field studies of S. densiflora in salt marshes across a wide latitudinal gradient from California (USA) to British Columbia (Canada) provided a model system for an integrated study of the potential mechanisms underlying the response of invasive S. densiflora populations to changes in environmental conditions. Our results showed that S. densiflora is able to adjust to widely variable climate (specifically, air temperature and the duration of the growing season) and sediment conditions (specifically, texture and hypoxia) through phenotypical plastic key functional tussock traits (e.g. shoot density, height, above- and below-ground biomass allocation patterns). Root biomass increased in coarser sediments in contrast to rhizomes, which were more abundant in finer sediments. Above-ground biomass and leaf area index increased mainly with air temperature during summer, and more robust (taller and wider) shoots were associated with more oxygenated sediments. In view of our results, S. densiflora appears to be a halophyte with a high degree of phenotypic plasticity that would enable it to respond successfully to changes in the abiotic conditions of salt marshes driven by global climate change, such as increasing salinity and temperatures.

Knowledge of factors that influence species colonization and abundance during ecological succession is key for conservation and restoration efforts. The tolerance of species to environmental stresses and interspecific interactions influence stages of ecological succession. Species with high tolerance to stress or high competitive ability, such as invasive species or transgressive hybrids, may acquire a relevant role in the succession, inhibiting its development. We studied the role of native Sarcocornia and exotic Spartina hybrids on vegetation succession in salt marshes. In a time span of ca. 12 years, halophyte community structure and key sedimentary characteristics were recorded in marshes that differ in geomorphology, physiography, and successional status. We evaluated vegetation change in a young marsh undergoing rapid primary succession, and in a mature marsh undergoing slow changes in composition within established vegetation. Native hybrids increased their abundance in both types of marshes over time. Their presence and persistence was concurrent with colonization by other native halophytes. While they did not dominate the community and impede native succession, it is interesting to note their colonization coincided with a decrease in cover of invasive Spartina densiflora. In contrast, exotic hybrids formed from S. densiflora changed successional trajectories through competitive displacement of native halophytes in the mature marsh. However, these hybrids were not yet present in the young marsh where S. densiflora had just started to invade. This study reveals contrasting roles of invasive and native hybrids during ecological succession, providing valuable new knowledge for the management and conservation of salt marshes.

Background and aims – The spread of invasive exotic species is one of the most important threats for salt marshes and cordgrasses (genus Spartina ) are among the most invasive halophytes. Recent analyses have revealed low levels of genetic diversity within the European cordgrass Spartina patens, clarifying that it was introduced from a narrow genetic pool of plants from North America. As biomass and intratussock structure are key functional traits in the ecological behaviour of cordgrasses, our aim was to document this here for the first time in Spartina patens in Europe.Methods – This work analyses above- and below-ground biomass and intratussock structure for two Spartina patens populations in Southern Spain in the two main invaded habitats in Europe, coastal dunes and brackish marshes.Key results – Spartina patens showed higher above-ground biomass and higher above: below-ground biomass ratio in the brackish marsh than on the coastal dunes due to higher live shoot densities with similar shoot heights. Sexual reproduction of Spartina patens was very limited in both studied populations since only a few inflorescences were recorded in just one tussock in the marsh.Conclusions – Our results for introduced Spartina patens in Spain are compared with those recorded for cohabiting cordgrasses, the native European Spartina maritima and the invasive Spartina densiflora, as well as with Spartina patens in North American marshes. Spartina patens appears as a species with moderate invasive potential in European coastal marshes and dunes since it shows very low sexual reproduction but a high phenotypic plasticity, which would support its invasive capacity. Eradication efforts are most cost effective in the early stage of infestation, when population sizes are still relatively small, and should thus be a focus of the control efforts of S. patens in the Southwest Iberian Peninsula as well as in other European areas, where this cordgrass is still not very abundant.

Salt marshes are being increasingly polluted by trace elements, and the design and implementation of management actions adapted to each particular situation are necessary. Salt marshes developed at one of the most heavy metal-polluted systems in the world, the Odiel and Tinto joint estuary, are threatened by high pollution levels, erosion and the invasion of the alien plant species Spartina densiflora, despite the high ecological values recognized by regional to international protection figures. Soft management on these marshes tries to preserve the equilibrium between conservation and decontamination. The ability of key native halophytes in the area to phytoextract or phytostabilizate trace elements has been taking into account. A local restoration project has resulted in a rapid recovery of the native prairies of low tidal marshes, dominated by S. maritima, becoming a promising tool to phytostabilize eroding areas in European marshes. These prairies also seem to stop the advance of the alien S. densiflora invasion and prevent erosion. On the other hand, areas invaded by S. densiflora are difficult to manage due to the acidity and pollution level of sediments preventing the establishment of any other plant species. Despite its invasive character, S. densiflora avoid at present the removal of highly toxic sediments and the trace element release to the food chain in this area.

Sedimentary abiotic environment, and concentration and stock of nine metals were analyzed in vegetation and sediments to evaluate the phytoremediation capacity of restored Spartina maritima prairies in the highly polluted Odiel Marshes (SW Iberian Peninsula). Samples were collected in two 10 -m long rows parallel to the tidal line at two sediments depths (0-2 cm and 2-20 cm). Metal concentrations were measured by inductively coupled plasma spectroscopy. Iron, aluminum, copper, and zinc were the most concentrated metals. Every metal, except nickel, showed higher concentration in the root zone than at the sediment surface, with values as high as ca. 70 g Fe kg(-1). The highest metal concentrations in S. maritima tissues were recorded in its roots (maximum for iron in Spartina roots: 4160.2 +/- 945.3 mg kg(-1)). Concentrations of aluminum and iron in leaves and roots were higher than in superficial sediments. Rhizosediments showed higher concentrations of every metal than plant tissues, except for nickel. Sediment metal stock in the first 20 cm deep was ca. 170.89 t ha(-1). Restored S. maritima prairies, with relative cover of 62 +/- 6%, accumulated ca. 22 kg metals ha(-1). Our results show S. maritima to be an useful biotool for phytoremediation projects in European salt marshes.

Ecological restoration of salt marshes using plantations may enhance the macroinvertebrate community, but little is known about the development of benthic macroinvertebrates after ecological engineering projects in European salt marshes. This study analyzed the environment and the macroinvertebrate community in European salt marshes 3 years after restoration using Spartina maritima plantations in comparison with non-restored and preserved marshes in Odiel Marshes (Southwest Iberian Peninsula). We hypothesized that planting Spartina maritima on intertidal mudflats would increase species richness and diversity (Shannon–Weaver index) of the benthic macroinvertebrate community by increasing environmental heterogeneity, providing feeding resources and improving sediments characteristics. Benthic macrofauna samples (composed mainly of annelids, crustaceans, and mollusks) were sampled in plots of 20 cm × 25 cm to 5 cm depth between +1.8 and +3.0 m above Spanish Hydrographic Zero. Sediment organic matter content, bulk density, pH, and redox potential were the variables that best explained macroinvertebrate distribution. Restored marshes achieved similar diversity and even higher specific richness than preserved marshes, although with differences in species composition. Non-restored marshes showed the lowest diversity. Restored and preserved marshes did not differ in total abundance or biomass of macroinvertebrates, both being higher than in non-restored marshes. The macroinvertebrate communities in preserved and non-restored marshes showed the largest difference in taxa composition, with restored marshes occupying an intermediate position. Salt marsh restoration using S. maritima increased the complexity (ecological diversity and species richness) and abundance of the benthic macroinvertebrate community. Our study offers new information about the role of salt marsh plants in mediating faunal communities via ecological engineering projects.

Only a few restoration projects incorporate public perception in their monitoring. However, participation of local people is a key process if social benefits are to be achieved. This study analyses, through a survey, citizens’ perceptions and usage of natural and restored coastal marshes in the city of Huelva (southwest Iberian Peninsula, Spain), as well as landscape preferences. Most of Huelva’s citizens recognised the benefits of coastal marshes (75%), a perception which increased with level of education. The majority of the respondents showed a low level of knowledge about the eco-lo-gical services and functions of salt marshes. In addition, visitor numbers to the studied restoration project increased by 27% after restoration. Regarding landscape preferences, most of the respondents preferred the native Chenopodiaceae salt marsh, and the native Spartina maritima landscape was chosen less often. In light of our results, environmental education campaigns should be carried out in the city of Huelv...

Capsule Salt marsh restoration with the native halophytes Spartina maritima and Zostera noltii can lead to significant improvement in habitat, increasing bird diversity over a 2-year period. Aims To assess the evolution of the avian communities in S. maritima restored salt marshes 2 years after planting, in comparison with adjacent non-restored marshes in the Odiel Marshes (southwest Iberian Peninsula). Methods Bird censuses were conducted from October 2008 to September 2009 in rectangular plots in three locations in both restored and non-restored marshes during high tides and low tides. Results A total of 44 bird species, including 20 shorebird species, were recorded. Most species belonged to Charadriidae, Scolopacidae, Laridae and Sterninae. Eight threatened bird species were recorded in restored marshes. Ecological diversity of the avian communities varied between 1.13 and 1.77. Restored marshes showed higher ecological diversity and evenness and lower Simpson dominance index than non-restored marshes. Conclusion Salt marsh restoration with the native halophytes S. maritima and Z. noltii can lead to significant short-term (over 2 years) improvements in bird diversity. © 2013 Copyright British Trust for Ornithology.

Salt marsh restoration projects using cordgrasses are relatively cheap and viable alternatives to improve the environmental quality while stabilizing sediments. This work quantifies the vertical sediment dynamics along the tidal gradient in low marshes in an extensive salt marsh restoration project, 26 months after planting Spartina maritima, in comparison with adjacent non-restored and preserved marshes in the Odiel Marshes (southwest Iberian Peninsula). The vertical sediment dynamics was recorded using markers consisting of an iron structure with two vertical posts and a horizontal crossbar, measuring the distance from the middle point of the crossbar to the sediment surface periodically between March 2009 and March 2011. The sediment dynamics was independent of the marsh elevation, depending mainly on plant cover. Erosion was lower in the S. maritima zone (mean accretion rate between +10 and +27 mm yr−1; mean accumulated erosion between +22 and +51 mm after 2 yr) than in bare intertidal mudflats (−14 to +12 mm yr−1; −36 to +37 mm after 2 yr). At higher elevations colonized by Sarcocornia perennis, sediment dynamics changed markedly, depending on marsh type (−10 to 14 mm yr−1; −31 to +29 mm after 2 yr). Extensive salt marsh plantations using S. maritima behaved in a similar way to natural preserved marshes after ca. 2 yr with a relative cover of 62%, this being a useful tool to stabilize eroding areas in European marshes, since they reduced erosion and increased accretion.

8 pages, 2 figures, 1 table, 29 references., Soils from four estuaries of SW Iberian Peninsula, affected by anthropogenic influence (urban, industrial and agricultural activities), were analyzed for the occurrence of a variety of metals and trace elements including Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S and Zn. The soils presented very high levels of salinity (high concentrations of Na, K and Mg), organic matter and, consequently, of C and N concentrations. In contrast, very low values of CaCO3,Ca and Pwere found. In addition, it should be highlighted that in certain localities (Piedras 1 and 2 and Guadiana in Huelva, Spain, and Ria Formosa, Faro, Portugal) the concentrations of Pb, S and Zn were extremely high, reaching levels of pollution., We thank the Spanish Science and Technology and Environmental Ministries for their support (projects 04212007 and PCI2006-A7-0641, respectively).

The South American cordgrass, Spartina densiflora, has invaded a range of different habitats that can support different native species assemblages on salt marshes in the Gulf of Cadiz, Spain. Little is known about the mechanisms of invasion. We examined the potential for seed germination and recruitment in a field transplant experiment, representing a wide range of environments, on elevational gradients across marshes with muddy and sandy sediments. The biotic resistance of native, perennial vegetation (where present) to recruitment of the alien was also investigated. Spartina densiflora seeds were able to germinate over a greater than 2-m range of elevation in the tidal frame. Germination success on unvegetated muddy sediments was related to sediment redox potential, with poor germination at strongly negative redox potentials on the lower sites. On sandy, well-drained sediments, germination was apparently constrained by water availability at the highest elevations. Comparison of vegetated and cleared plots on the upper marsh showed that there was a negative relationship between the presence of Atriplex portulacoides and germination on the muddy sediments. Recruitment (survival of seedlings for 12 weeks) was seen only on unvegetated muddy sediments at the highest elevation. Hence the invasive success and wide elevational tolerance of S. densiflora on the marshes of the Gulf of Cadiz are not reflected in its short-term ability to become established from its prolific seed production. Colonization of sub-optimal habitats may be largely by vegetative propagules and clonal growth.

The South American cordgrass Spartina densiflora is invading European salt marshes getting into contact with the indigenous and endangered low-marsh dominant, Spartina maritima. This work describes the evolution of the plant zonation during 7 years in a marsh of S. maritima invaded by S. densiflora. S. maritima appeared throughout the whole intertidal gradient from 1.72 to 3.33 m over Spanish Hydrographic Zero (SHZ), showing its higher biomasses and shoot densities at low elevations. In contrast, S. densiflora only invaded upper areas (>+2.59 m SHZ) at the centre of circular tussocks of S. maritima. Above-ground biomass of S. maritima dropped drastically at maximum occupation of space by the alien, and its shoot density and above-ground biomass decreased at S. densiflora zone during the study. The competitive potential of S. densiflora was reflected in high above- and below-ground biomass and shoot densities, accompanied by elevated wrack accumulation and the absence of other marsh plants presented together with S. maritima from areas dominated by S. densiflora. S. densiflora altered the native vegetational zonation pattern through the invasion of the centre of S. maritima tussocks; however, the alien invasion may be limited by the presence of the autochthonous cordgrass at lower elevations.

Spartina species are commonly used for salt marsh manipulative projects, where aboveground and belowground biomasses are functional traits that play important roles, showing high spatial and temporal variations. This work analyses variations in AGB and BGB of Spartina maritima and abiotic environmental parameters along a chronosequence of six marshes created from 1997 to 2003 with disparate sediment dynamics, and adjacent natural marshes and unvegetated tidal flats. S. maritima behaved as an autogenic engineer, as its colonization of bare sediments yielded abiotic environmental changes: specifically, bed level rise accompanied by higher oxygenation and salinity. These modifications of the environment were site-specific, depending mainly on sedimentary dynamics. At the same time, abiotic environmental changes determined biomass production rates of S. maritima that were higher in more-accreting marshes; however, AGB was kept constant from early in its development (2 years). The increase in BGB with elevation seemed to be related to the inhibition of subsurface tissue development in anoxic sediments. Biomass accumulation and production varied markedly, depending on the spatial scale, indicating the relevance of the plot size chosen for the analysis of biomass of cordgrasses. Our results show that managers of salt marshes should consider sedimentary dynamics carefully when setting realistic expectations for success criteria of created and restored wetlands.

We analyzed variations in the life span of the invasive cordgrass Spartina densiflora at low marshes of SW Iberian Peninsula, and identified the abiotic factors limiting the plant in the absence of competition. With these objectives, clump survivorship, flowering, and growth of S. densiflora were studied in two natural populations at different low marsh elevations during more than three years, and at a transplant experiment in comparison with the native Spartina maritima. The life spans of both cordgrasses changed depending on small variations of a few centimeters in elevation. S. maritima, which tolerates better than S. densiflora the stressful abiotic environment of lower marshes, showed a significant lower distribution limit for its perennial habit, with survivorship longer than three years (from 1997 to 2000), than the neophyte (+1.57 m SHZ vs. +2.00 m SHZ). S. densiflora clumps flowered before dying at mostly all elevations, showing low relative growth rates. In contrast, clumps of S. maritima, with non-viable seeds, only flowered when they were three years old at higher elevations in the low marsh. Our results have applications for salt marshes bioengineering projects and to prevent S. densiflora from invading European marshes since our data improve the knowledge of its colonization mechanisms through salt marsh zonation and so identify those portions of restored and native marshes most susceptible to invasion due to the establishment of perennial populations.

Background and Aims: Atriplex(Halimione) portulacoides is a halophytic, C3 shrub. It is virtually confined to coastal salt marshes, where it often dominates the vegetation. The aim of this study was to investigate its growth responses to salinity and the extent to which these could be explained by photosynthetic physiology. • Methods: The responses of young plants to salinity in the range 0-700 mol m-3 NaCl were investigated in a glasshouse experiment. The performance of plants was examined using classical growth analysis, measurements of gas exchange (infrared gas analysis), determination of chlorophyll fluorescence characteristics (modulated fluorimeter) and photosynthetic pigment concentrations; total ash, sodium, potassium and nitrogen concentrations, and relative water content were also determined. • Key Results: Plants accumulated Na+ approximately in proportion to external salinity. Salt stimulated growth up to an external concentration of 200 mol m-3 NaCl and some growth was maintained at higher salinities. The main determinant of growth response to salinity was unit leaf rate. This was itself reflected in rates of CO2 assimilation, which were not affected by 200 mol m-3 but were reduced at higher salinities. Reductions in net photosynthetic rate could be accounted for largely by lower stomatal conductance and intercellular CO2 concentration. Apart from possible effects of osmotic shock at the beginning of the experiment, salinity did not have any adverse effect on photosystem II (PSII). Neither the quantum efficiency of PSII (ΦPSII) nor the chlorophyll fluorescence ratio (Fv/Fm) were reduced by salinity, and lower mid-day values recovered by dawn. Mid-day Fv/Fm was in fact depressed more at low external sodium concentration, by the end of the experiment. • Conclusions: The growth responses of the hygro-halophyte A. portulacoides to salinity appear largely to depend on changes in its rate of photosynthetic gas exchange. Photosynthesis appears to be limited mainly through stomatal conductance and hence intercellular CO2 concentration, rather than by effects on PSII; moderate salinity might stimulate carboxylation capacity. This is in contrast to more extreme halophytes, for which an ability to maintain leaf area can partially offset declining rates of carbon assimilation at high salinity. Ministerio de Ciencia y Tecnología CTM2005-05011

Experimental studies to determine the nature of ecological interactions between invasive and native species are necessary for conserving and restoring native species in impacted habitats. Theory predicts that species boundaries along environmental gradients are determined by physical factors in stressful environments and by competitive ability in benign environments, but little is known about the mechanisms by which hydrophytes exclude halophytes and the life history stage at which these mechanisms are able to operate. The ongoing invasion of the South AmericanSpartina densiflorain European marshes is causing concern about potential impacts to native plants along the marsh salinity gradient, offering an opportunity to evaluate the mechanisms by which native hydrophytes may limit, or even prevent, the expansion of invasive halophytes. Our study comparedS. densifloraseedling establishment with and without competition withPhragmites australisandTypha domingensis, two hydrophytes differing in clonal architecture. We hypothesized that seedlings of the stress tolerantS. densiflorawould be out-competed by stands ofP. australisandT. domingensis. Growth, survivorship, biomass patterns and foliar nutrient content were recorded in a common garden experiment to determine the effect of matureP. australisandT. domingensison the growth and colonization ofS. densifloraunder fresh water conditions where invasion events are likely to occur. MatureP. australisstands prevented establishment ofS. densifloraseedlings andT. domingensisreducedS. densifloraestablishment by 38%. Seedlings grown withP. australisproduced fewer than five short shoots and all plants died after ca. 2 yrs. Our results showed that direct competition, most likely for subterranean resources, was responsible for decreased growth rate and survivorship ofS. densiflora. The presence of healthy stands ofP. australis, and to some extentT. domingensis, along river channels and in brackish marshes may prevent the invasion ofS. densifloraby stopping the establishment of its seedlings.

Salt marshes offer a valuable opportunity to study the effects of environment on the clonal growth of species able to live throughout a wide vertical range on the tidal frame. Spartina densiflora is a species native to South America that is invading marshes in SW Europe, NW Africa, and SW North America, where its populations are found from low to high topographic elevations, altering the composition of plant communities. The aim of this study was to increase our knowledge regarding the competitive ability of S. densiflora, analyzing its clonal growth and its ramet demography during 25 months in two expanding populations at a low and a high marsh. Four clonal characteristics were recorded in both populations: (1) dense occupation of available space inside tussocks; (2) lack of a dormant period and high tiller production rates and growth; (3) evidence of physiological integration between ramets; and (4) high rates of sexual reproduction. Furthermore, S. densiflora developed different strategies of clonal growth in contrasting habitats. Tussocks in the low marsh had lower tiller longevity and higher tiller density, natality, and mortality rates, showing faster ramet turnover than in the high marsh. These clonal growth traits would facilitate S. densiflora persistence under the effects of catastrophic events. Spartina densiflora clonal growth traits indicate strong adaptability to different environmental conditions and strong competitive ability, since its tiller dynamics enable it to invade occupied space, and it effectively colonizes new safe-sites by sexual reproduction. These observations help us to understand how this invader has become the most abundant plant in many estuaries of the SW Iberian Peninsula.

Ecological restoration and creation of salt marshes is needed to compensate for their degradation and loss, but little is known about halophytes as plant biotools in restoration projects. The aim of this study was to evaluate Sarcocornia perennis spp. perennis ,a common halophyte in European, Southern Africa and SouthAmerica saltmarshes,as a restoration biotool. We analysed S. perennis sedimentary habitat and quantified its biomass production and the concentration and stock of carbon, nitrogen and nine metals (Al, As, Cd, Cr, Cu, Fe, Ni, Pb and Zn) in the tissues of S. perennis, 28 months after plantation in an innovative restoration project in the Odiel Marshes. S. perennis had accumu- lated above-ground biomass values (ca. 1,600 g dry weight(DW)m −2 ) within the range recorded previously for naturalpopulations, but root biomass was lower than for mature natural populations. S. perennis prairies accumulated 299 g C m −2 year −1 and 25 g N m −2 year −1 . With the exception of Pb and As, plant transfer coefficient results document the ability of transplanted S. perennis to hyperaccumulate nearly ev- ery metal we measured. The highest metal concentra- tions were recorded in S. perennis ssp. perennis roots (translocation coefficient lower than 1.0 for every met- al). Our results provide strong support for the use of S. perennis ssp. perennis transplants as a biotool for salt marsh restoration at low-medium elevations in the tidal gradient. Use oflivevegetationfor metal extractionmay enhance other restoration functions including phytostabilization, reduced eutrophication and negative effects of climate change.

Premise of the study: Phenotypic acclimation of individual plants and genetic differentiation by natural selection within invasive populations are two potential mechanisms that may confer fi tness advantages and allow plants to cope with environmental variation. The invasion of Spartina densifl ora across a wide latitudinal gradient from California (USA) to British Columbia (Canada) provides a natural model system to study the potential mechanisms underlying the response of invasive populations to substantial variation in climate and other environmental variables. Methods: We examined morphological and physiological leaf traits of Spartina densifl ora plants in populations from invaded estuarine sites across broad latitudinal and climate gradients along the Pacifi c west coast of North America and in favorable conditions in a common garden experiment. Key results: Our results show that key foliar traits varied widely among populations. Most foliar traits measured in the fi eld were lower than would be expected under ideal growing conditions. Photosynthetic pigment concentrations at higher latitudes were lower than those observed at lower latitudes. Greater leaf rolling, reduced leaf lengths, and lower chlorophyll and higher carbon concentrations were observed with anoxic sediments. Lower chlorophyll to carotenoids ratios and reduced nitrogen concentrations were correlated with sediment salinity. Our results suggest that the variations of foliar traits recorded in the fi eld are a plastic phenotypic response that was not sustained under common garden conditions. Conclusions: Spartina densifl ora shows wide differences in its foliar traits in response to environmental heterogeneity in salt marshes, which appears to be the result of phenotypic plasticity rather than genetic differentiation. Fil: Castillo, Jesus M.. Universidad de Sevilla; España Fil: Grewell, Brenda J.. University Of California At Davis; Estados Unidos Fil: Pickart, Andrea. Humboldt Bay National Wildlife Refuge; Estados Unidos Fil: Bortolus, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Peña, Carlos. Universidad de Sevilla; España Fil: Figueroa, Enrique. Universidad de Sevilla; España Fil: Sytsma, Mark. Portland State University; Estados Unidos

The use of exotic cordgrasses in salt marsh restoration projects has caused important negative environmental impacts and little is known about the possibilities of applying the endangered cordgrass Spartina maritima as a biotool at many European estuaries where it is the only native cordgrass. This paper discusses the planning and the development of an innovative restoration project based on S. maritima plantations in Odiel marshes (S.W. Iberian Peninsula). Our ecological restoration project had four specific goals: (1) to recover native vegetation, restoring the degraded landscape; (2) to phytostabilize oil-polluted sediments; (3) to prevent erosion and stabilize banks; and (4) to promote the conservation of S. maritima. Spartina maritima was planted at two physiographical locations: slightly sloping channel banks and flat interior marshes. Nonsuccessional stands of S. maritima develop at the channel banks where the marsh surface was stabilized. In contrast, successional stands of S. maritima grown in flat interior marshes are being replaced naturally by Sarcocornia perennis.

Restoration of salt marshes is critical in the context of climate change and eutrophication of coastal waters because their vegetation and sediments may act as carbon and nitrogen sinks. Our primary objectives were to quantify carbon (C) and nitrogen (N) stocks and sequestration rates in restored marshes dominated by Spartina maritima to provide support for restoration and management strategies that may offset negative aspects of eutrophication and climate change in estuarine ecosystems. Sediment C content was between ca. 13 mg C g(-1)and sediment N content was ca. 1.8 mg N g(-1). The highest C content for S. maritima was recorded in leaves and stems (ca. 420 mg C g(-1)) and the lowest in roots (361 ± 4 mg C g(-1)). S. maritima also concentrated more N in its leaves (31 ± 1 mg N g(-1)) than in other organs. C stock in the restored marshes was 29.6 t C ha(-1); ca. 16 % was stored in S. maritima tissues. N stock was 3.6 t N ha(-1), with 8.3 % stored in S. maritima. Our results showed that the S. maritima restored marshes, 2.5 years after planting, were sequestering atmospheric C and, therefore, provide some mitigation for global warming. Stands are also capturing nitrogen and reducing eutrophication. The concentrations of C and N contents in sediments, and cordgrass relative cover of 62 %, and low below-ground biomass (BGB) suggest restored marshes can sequester more C and N. S. maritima plantations in low marshes replace bare sediments and invasive populations of exotic Spartina densiflora and increase the C and N sequestration capacity of the marsh by increasing biomass production and accumulation.

Curado, G.; Rubio-Casal, A.E.; Figueroa, E., and Castillo, J.M., 2014. Plant zonation in restored, nonrestored, and preserved Spartina maritima salt marshes. Journal of Coastal Research, 30(3), 629–634. Coconut Creek (Florida), ISSN 0749-0208. This study analyzes the vegetation zonation and the abiotic environment (sediment elevation, pH, redox potential, and electrical conductivity) 2.5 years after salt marsh restoration using Spartina maritima and Sarcocornia perennis plantations in the Odiel Marshes (SW Iberian Peninsula) in comparison with preserved and degraded marshes. Restored marshes presented higher species richness (10 spp.) than nonrestored (6 spp.) and preserved (3 spp.) marshes, as a result of milder abiotic conditions (more oxygenated sediments than preserved marshes) and higher habitat diversity (sandy patches at higher elevations). Marshes restored using S. maritima (planted at a density of 1 clump m � 2 ) achieved a similar relative cover to preserved marshes (ca. 50%) 2.5 years after transplanting. Spartina maritima showed higher tiller height in preserved (40 6 2 cm) than in restored marshes (34 6 1c m).Sarcocornia perennis cover was similar in the three areas, being concentrated at higher elevations in the tidal gradient. Our results show the success from the point of view of vegetation of restoring European low salt marshes using S. maritima and S. perennis plantations, since they are able to reproduce, 2.5 years after restoration, the typical zonation pattern.