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A debate over the impacts of invasive plants is fueled by varied terminology, ecosystem types, response metrics, and conflicting evidence across scales. We quantify the effects of invading Phalaris arundinacea (Pa) on species richness and abundance in Wisconsin sedge meadows dominated by Carex stricta (Cs). Among species area curves from four nested plots (0.25, 1, 4, and 16 m) in seven sites, Pa stands averaged 48 % fewer species than the adjacent Cs. Species richness was reduced by about half regardless of plot size. Total richness for Pa stands was 50 species compared to 83 for Cs, and Pa stands had consistently lower additive percent cover of subordinate species at all scales. However, resident species responded differentially to Pa invasion. Only one species, Calamagrostis canadensis (a tall clonal grass), had similar importance values (using cover and frequency) in Cs and Pa stands at 0.25 and 16-m scales. Other species declined with Pa invasion, mostly in frequency. Despite losing half of their resident species, sites did not differ significantly in their native exotic richness relationship (NERR). NERR confounds the effects of invasiveness with species' origins, and it under-represents impacts of dominant invaders in wetlands. Debates should be fewer if studies specify if the invader is exotic or native, type of invaded ecosystem, the metric used to assess responses, and the spatial scale. [ABSTRACT FROM AUTHOR]

In 2005, a 7-ha artificial watershed (Chicken Creek) was built on a post mined landscape in Lusatia, Germany from sandy substrates of Pleistocene origin, commonly used in reclamation. The watershed was developed to investigate the initial phase of soil and ecosystem development under natural conditions. At this early stage, mineral nitrogen in young sandy soils is primarily limited and nitrogen fixing legumes become key components of natural succession. Local abundant pioneering legumes Lotus corniculatus and Trifolium arvense and one pioneer grass species Calamagrostis epigeios were investigated 5 years after watershed construction. In this study, we investigated the influence of spatial root and nodule distribution of these species on soil nitrogen accumulation. Soil, including roots, was sampled from field monoliths covered with the aforementioned plant species. Root systems of both legumes were mainly restricted to the upper 20 cm of soil, whereas roots of C. epigeios also developed strongly at greater depths. A positive relationship was found, with higher plant densities associated with higher root densities which were associated with higher nodule densities for legumes and which were all associated with significantly higher soil nitrogen content relative to non-vegetated areas. This research provides rare information on the role root systems of pioneer legumes play in soil nitrogen input in the early stage of soil and ecosystem development during revegetation by natural succession. [ABSTRACT FROM AUTHOR]

Post-mining restoration sites often develop novel ecosystems as soil conditions are completely new and ecosystem assemblage can be spontaneous even on afforested sites. This study presents results from long-term monitoring and evaluation of an afforested oil-shale quarry in Estonia. The study is based on chronosequence data of soil and vegetation and comparisons are made to similar forest site-types used in forest management in Estonia. After site reclamation, soil development lowered pH and increased N, K, and organic C content in soil to levels similar to the common Hepatica forest site-type but P, total C, and pH were more similar to the Calamagrostis forest site-type. Vegetation of the restoration area differed from that on common forest sites; forest stand development was similar to the Hepatica forest-type. A variety of species were present that are representive of dry and wet sites, as well as infertile and fertile sites. It appears that novel ecosystems may be developing on post-mining reclaimed land in Northeast Estonia and may require adaptations to typical forest management regimes that have been based on site-types. Monitoring and evaluation gives an opportunity to plan further management activities on these areas. [ABSTRACT FROM AUTHOR]

This article focuses on assessing the habitats characteristics of endangered Calamagrostis pseudophragmites in selected localities in the Czech Republic with different river engineering measures, which can potentially influence the occurrence of this species. Furthermore, we give some general recommendations for management practices based on our results to promote the conservation of Calamagrostis pseudophragmites . Our research shows that there is a high correlation between Calamagrostis pseudophragmites and natural or near natural sunny biotopes on gravel bars or straight reaches near the water level that consist of non-silted gravel substrates with a higher concentration of pebbles or cobbles, which are typical of piedmont and mountain-valley areas. Many of these areas are rapidly disappearing due to intensive anthropogenic pressure. We also found that Calamagrostis pseudophragmites is temporarily capable of surviving among other competitively stronger plant communities. To assess the potential influence of river engineering we selected two different types of rivers where this species is present – one was heavily altered by both the construction of a water reservoir in its upper reach and channelization of the stream, the other was less severely regulated by the construction of several weirs. Our results show differences in the occurrence of Calamagrostis pseudophragmites between the two rivers, being found at three times as many localities in the less regulated river than in the more regulated one. This corresponds with a higher number of gravel bars in the less regulated river. Based on our results, our general recommendations for the management of this species include only the partial removal of gravel bars (to ensure flood control in populated areas), blocking vegetation succession by removing woody vegetation and aggressive invasive species, the restoration of natural river dynamics, and connecting existing biotopes where this species is found. [ABSTRACT FROM AUTHOR]

There are large temporal and spatial variations of methane (CH) emissions from natural wetlands. To understand temporal changes of CH production potential (MPP), soil samples were collected from a permanently inundated Carex lasiocarpa marsh and a summer inundated Calamagrostis angustifolia marsh over the period from June to October of 2011. MPP, dissolved organic carbon (DOC) concentration, abundance and community structure of methanogenic archaea were assessed. In the C. lasiocarpa marsh, DOC concentration, MPP and the methanogen population showed similar seasonal variations and maximal values in September. MPP and DOC in the C. angustifolia marsh exhibited seasonal variations and values peaked during August, while the methanogen population decreased with plant growth. Methanogen abundance correlated significantly ( P = 0.02) with DOC only for the C. lasiocarpa marsh. During the sampling period, the dominant methanogens were the Methanosaetaceae and Zoige cluster I (ZC-Ι) in the C. angustifolia marsh, and Methanomicrobiales and ZC-Ι in the C. lasiocarpa marsh. MPP correlated significantly ( P = 0.04) with DOC and methanogen population in the C. lasiocarpa marsh but only with DOC in the C. angustifolia marsh. Addition of C. lasiocarpa litter enhanced MPP more effectively than addition of C. angustifolia litter, indicating that temporal variation of substrates is controlled by litter deposition in the C. lasiocarpa marsh while living plant matter is more important in the C. angustifolia marsh. This study indicated that there was no apparent shift in the dominant types of methanogen during the growth season in the species-specific freshwater wetlands. Temporal variation of MPP is controlled by substrates and substrate-driven changes in the abundance of methanogenic archaea in the C. lasiocarpa marsh, while MPP depends only on substrate availability derived from root exudates or soil organic matter in the C. angustifolia marsh. [ABSTRACT FROM AUTHOR]

Lodgepole pine ( Pinus contorta var. latifolia) stands were sampled in central Yukon, Canada (61.5-64°N latitude), which represented the northernmost 9% of the tree's North American range. Within this area, lodgepole pine occupied only ˜ 2% of the landscape. This study determined: 1) what forest sociations occurred (i.e. structural dominance-types); 2) how plant growth form composition and richness differed from the central portion of the species' geographical range; and 3) if stands were biased towards occurring on more thermally favorable south-facing slopes. Five lodgepole pine sociations were recognized among 100 relevés: Rhododendron groenlandicum (Labrador tea); Cladonia arbuscula (green reindeer lichen); Calamagrostis purpurascens (purple reedgrass); Hylocomium splendens (stairstep moss) and Alnus viridis (green alder, n = 4 relevés). Rhododendron stands were proportionally more common on low gradient sites and had more total plant cover than the other sociations. Cladonia and Calamagrostis stands were typically associated with dry coarse-textured soils and warm dry sites, respectively; whereas the composition of the Hylocomium sociation reflected the detrimental influences of atypically dense forest canopies on understory vascular plants. Only the Calamagrostis sociation was unique to the study region. Species richness among common northern lodgepole pine sociations averaged 16-19 taxa per relevé (p > 0.05). Northern compared to central range (n = 1394) relevés were compositionally different based on little overlap of their datasets in the ordination space. Northern vegetation had less (p < 0.001) total plant (129% vs 184%), deciduous shrub (9% vs 26%), broad-leaved herb (5% vs 25%), and bryophyte (27% vs 54%) cover; had greater macro-lichen cover (13% vs 5%) and lower floristic richness (11 vs 24 taxa) and was less than half as phytosociological diverse. Lodgepole pine stands in the northernmost portion of their range were not biased towards occurring on south-facing slopes, which suggested an ecological potential for range expansion. [ABSTRACT FROM AUTHOR]

Canada bluejoint grass [Calamagrostis canadensis(Michx.) P. Beauv., hereafter referred to as bluejoint] outcompetes overstory tree species such as white spruce [Picea glauca(Moench) Voss] by creating a thick litter layer and competing for the available nitrogen (N). This study was conducted to investigate the effects of bluejoint litter layer (with or without litter removal) and N fertilization on soil water and N availabilities using principal component analysis (PCA) and foliar δ15N and δ13C of bluejoint in a plantation in north-central Alberta, Canada. PCA using soil properties and understory growth data demonstrated that N fertilization was more effective in changing the soil environment and resource availabilities for bluejoint growth than litter layer removal. The increase in soil N availability by N fertilization was linked with increased bluejoint foliar δ15N (by around 3‰) in fertilized plots, as a result of greater N isotopic fractionation in the fertilized plots. The more negative δ13C (by around 1‰) of bluejoint in litter layer-removed plots suggested that litter layer removal increased soil water availability, indicating that the litter layer reduced soil water availability on the site. Therefore, results from this and previous studies showed that the litter layer decreased both soil water and N availabilities. Although the exact mechanisms of the benefit of the litter layer for bluejoint remains unknown, bluejoint likely adversely impacted tree growth by competing for N due to its strong N acquisition ability under soil resource-limiting conditions. [ABSTRACT FROM PUBLISHER]

Background: The Three Gorges project has caused many ecosystem problems. Ecological restoration using readily-available plants is an effective way of mitigating environmental impacts. Two perennial submergence-tolerant ecotypes of Calamagrostis arundinacea were planted in an experimental field in the drawdown zone. Responses of the two plant ecotypes to flooding stress in the drawdown zone were unknown. Methodology/Principal Findings: Carbohydrate content and membrane stability, two key factors for survival of plants under flooding stress, of two ecotypes (designated “dwarf” and “green”) of C. arundinacea growing at different elevations of the drawdown zone were investigated. Live stems (LS) and dead stems (DS) of the two plant ecotypes at eight elevations (175, 170, 162, 160, 158, 155, 152 m and 149 m) were sampled. Contents of soluble sugar, starch and malondialdehyde (MDA), as well as plasma membrane permeability of live stems were measured. The lowest elevations for survival of dwarf and green C. arundinacea were 160 m and 158 m, respectively. Soluble sugar content of live stems of both ecotypes decreased with elevation, with amounts from an elevation of 170 m being lower than from an elevation of 175 m. MDA content and plasma membrane permeability in live stems of green C. arundinacea did not increase with the decrease in elevation, while these measures in dwarf C. arundinacea from an elevation of 162 m were significantly higher than from an elevation of 175 m. Conclusions: Carbohydrate content, especially soluble sugar content, in both ecotypes was more sensitive to flooding stress than membrane stability. Green C. arundinacea had a higher tolerance to submergence than dwarf C. arundinacea, and thus green C. arundinacea can be planted at lower elevations than dwarf C. arundinacea. [ABSTRACT FROM AUTHOR]

Highlights: [•] Species richness/seedling emergence decreased significantly with sediment addition. [•] Native species disappeared from sediment disturbed wetland. [•] Plant species responded differently to the addition of sediment. [•] Knowledge gained from this study will provide insight into irrigation management. [ABSTRACT FROM AUTHOR]

For the District of Lircay, we report a total of 46 species and one subspecies of the Poaceae family, grouped into 21genera, 11 tribes and 6 subfamilies. The genus Calamagrostis is the most diverse with 9 species, followed by Poa with 5 species. Also, Aciachne acicularis "paccupaccu", Arundo donax "carrizo", Cortaderia hieronymi and Ortachne erectifolia "iruichu" are new reports for the region of Huancavelica. Moreover, dichotomous keys are presented for the determination of species in the case a genus has more than one species. For each species, data on habitat, distribution, examined material and common name are included. [ABSTRACT FROM AUTHOR]

The effects of nitrogen deposition (N-deposition) on the carbon dynamics in typical Calamagrostis angustifolia wetland of Sanjiang Plain were studied by a pot-culture experiment during two continuous plant growing seasons. Elevated atmospheric N-deposition caused significant increases in the aboveground net primary production and root biomass; moreover, a preferential partition of carbon to root was also observed. Different soil carbon fractions gained due to elevated N-deposition and their response intensities followed the sequence of labile carbon > dissolved organic carbon > microbial biomass carbon, and the interaction between N-deposition and flooded condition facilitated the release of different carbon fractions. Positive correlations were found between CO2 and CH4 fluxes and liable carbon contents with N-deposition, and flooded condition also tended to facilitate CH4 fluxes and to inhibit the CO2 fluxes with N-deposition. The increases in soil carbon fractions occurring in the nitrogen treatments were significantly correlated with increases in root, aboveground parts, total biomass, and their carbon uptake. Our results suggested that N-deposition could enhance the contents of active carbon fractions in soil system and carbon accumulation in plant of the freshwater wetlands. [ABSTRACT FROM AUTHOR]

The efficiency of biogeochemical mapping for identifying acid sulphate soils (AS soils) was studied by sampling and analysing water, transplanted aquatic moss (Fontinalis antipyretica) and leaves of the vascular plant Calamagrostis purpureaat two sites in a stream in northern Sweden with AS soils in its drainage area. One upstream sampling station (Mårtsmarken) was situated in an area dominated by till, and a downstream station (Persraningen) was situated in an area where AS soils are common. Metal contents in F. antipyreticaand C. purpureaat these sites were compared to those in water (both unfiltered samples, and samples subjected to 0.22 µm membrane filtration and 1 kDa ultrafiltration to obtain data on metal speciation and its effects on uptake). Oxidation of sulphides with associated increases in acidity and release of metals were clearly reflected by differences in the water samples. At Persraningen the pH was lower than at Mårtsmarken, and the unfiltered concentrations of Al, Ca, Cd, Co, Cu, K, Mg, Mn, Ni, P, S, Sr, Y and Zn were higher. At the upstream station, Mårtsmarken, the suspended fraction was an important carrier of Fe and P, and the colloidal concentrations were higher than or similar to the dissolved concentrations for all determined elements except Na and K. At Persraningen the low pH resulted in changes of speciation, so that the dissolved concentrations were higher than the colloidal concentrations for most elements. For Al, As, Cr, Cu, Pb and Y, the dissolved and colloidal concentrations were similar. For Fe, the colloidal concentration was usually higher than the dissolved concentration, and suspended Fe was detected. Aluminium, Cr, Cu, Fe and Y concentrations were significantly higher in Fontinalis antipyreticaat Persraningen than at Mårtsmarken. In addition, concentrations of Al and Fe in C. purpureawere significantly higher at Persraningen. Our results highlight the potential of biogeochemical mapping for predicting the occurrence of AS soils. A limitation is the strong pH dependence of the uptake of metals in the aquatic mosses resulting in that only a few of the elements typically occurring at high concentrations in waters draining AS soils are enriched in the macrophytes. A combination of maps showing both absolute concentrations and elemental ratios would be useful for this, including not only ratios of previously suggested utility (e.g. Y:Pb and Ni:Pb), but also others, such as Y:Ca, Al:Ca, Cu:Ca, Y:Mg, Al:Mg and Cu:Mg. [ABSTRACT FROM AUTHOR]

Sedge meadows can be difficult to restore from farmed fields if key structural dominants are missing from propagule banks. In hand-cultivated soybean fields in northeastern China, we asked if tussock-forming Carex and other wetland species were present as seed or asexual propagules. In the Sanjiang Plain, China, we compared the seed banks, vegetative propagules (below-ground) and standing vegetation of natural and restored sedge meadows, and hand-cultivated soybean fields in drained and flooded conditions. We found that important wetland species survived cultivation as seeds for some time (e.g. Calamogrostis angustifolia and Potamogeton crispus) and as field weeds (e.g. C. angustifolia and Phragmites australis). Key structural species were missing in these fields, for example, Carex meyeriana. We also observed that sedge meadows restored without planting or seeding lacked tussock-forming sedges. The structure of the seed bank was related to experimental water regime, and field environments of tussock height, thatch depth, and presence of burning as based on Nonmetric Multidimensional Scaling analysis. To re-establish the structure imposed by tussock sedges, specific technologies might be developed to encourage the development of tussocks in restored sedge meadows. [ABSTRACT FROM AUTHOR]

Question Diversification of grassland management is recommended as a tool for conservation of different taxonomic groups living in those habitats. How resistant and resilient are species-rich grasslands in terms of plant species richness and vegetation composition to short-term, small-scale perturbations caused by changes in management practice? Location Bílé Karpaty Mountains, SE Czech Republic. Methods The experiment included the effect of six management regimes (mowing in June; mowing in September; mowing in June and September; mowing in June and high stubble left; no management; mowing in June and mulching). It was conducted in species-rich wooded grasslands in the White Carpathians Mts., Czech Republic, represented by three types of plant community: a Bromus erectus community (with high species richness and low productivity), a Molinia arundinacea community (with high species richness and high productivity), and a Calamagrostis epigejos community (with low species richness and high productivity). After 3 yr, resistance was assessed, and traditional management (mowing once each year in June) was resumed; resilience was evaluated after three more years. Results While the species-rich, unproductive Bromus community was relatively resistant to less intensive management in terms of species richness, and therefore its resilience could not be assessed, it changed substantially in terms of vegetation composition (maximum dissimilarity between control and abandoned plots was 63%). The more productive Molinia and Calamagrostis communities lost up to 37% of species due to abandonment, but not as a consequence of other changes management regimes. After the traditional management was resumed, resilience was higher in the Calamagrostis community than in the Molinia community. Vegetation composition was not affected by treatments. Conclusions The results show that short-term abandonment causes loss of plant diversity in productive grasslands but not in less productive, species-rich grasslands in the short term. Other relaxed management regimes (e.g. high stubble and delayed mowing) were comparable with the control and can be used for a short time to increase diversity of management without an effect on plant species richness. However, further research is needed to assess the effects of these management practices when they are applied repeatedly or over the long term. [ABSTRACT FROM AUTHOR]

Abstract: Linear matrix models of stage-structured population dynamics are widely used in plant and animal demography as a tool to evaluate the growth potential of a population in a given environment. The potential is identified with λ 1, the dominant eigenvalue of the projection matrix, which is compiled of stage-specific transition and fertility rates. Advanced botanical studies reveal polyvariant ontogeny in perennial plants, i.e., multiple different versions of individual development within a local population of a single species. This phenomenon complicates any standard, successive-stage, life cycle graph to a digraph defined on a 2D lattice in the age and stage dimensions, the pattern of projection matrix becoming more complex too. In a kind of experimental design, the transition rates can be calculated directly from the data for two successive time moments, but the age-stage-specific rates of reproduction still remain uncertain, adding more complexity to the calibration problem. Simple additional assumptions could technically eliminate the uncertainty, but they contravene the biology of a species in which polyvariant ontogeny is considered to be the major mechanism of adaptation. Given the data and expert constraints, the calibration can be reduced instead to a nonlinear maximization problem, yet with linear constraints. I prove that it has a unique solution to be attained at a vertex of the constraint polyhedral. To facilitate searching for the solution in practice, I use the net reproductive rate R 0, a well-known indicator for the principal property of λ 1 to be greater or less than 1. The method is exemplified with the calibration of a projection matrix in an age-stage-structured model (published elsewhere) for Calamagrostis canescens, a perennial herbaceous species with a complex (multivariant) life cycle that features unlimited growth when colonizing open areas. [Copyright &y& Elsevier]

In initial ecosystems, concentrations of all macroand micronutrients can be considered as extremely low. Plant litter therefore strongly influences the development of a degrader's food web and is an important source for C and N input into soil in such ecosystems. In the present study, a 13C litter decomposition field experiment was performed for 30 weeks in initial soils from a post-mining area near the city of Cottbus (Germany). Two of this region's dominant but contrasting pioneering plant species (Lotus corniculatus L. and Calamagrostis epigejos L.) were chosen to investigate the effects of litter quality on the litter decomposing microbial food web in initially nutrient-poor substrates. The results clearly indicate the importance of litter quality, as indicated by its N content, its bioavailability for the degradation process and the development of microbial communities in the detritusphere and soil. The degradation of the L. corniculatus litter, which had a low C /N ratio, was fast and showed pronounced changes in the microbial community structure 1-4 weeks after litter addition. The degradation of the C. epigejos litter material was slow and microbial community changes mainly occurred between 4 and 30 weeks after litter addition to the soil. However, for both litter materials a clear indication of the importance of fungi or the degradation process was observed both in terms of fungal abundance and activity (13C incorporation activity) [ABSTRACT FROM AUTHOR]

DewaxedCalamagrostis angustifoliaKom was pretreated with hot water at 60 and 90°C for 3 h, and then the residue obtained was successively treated with 70% ethanol, and 70% ethanol containing 0.2%, 1.0%, 2.0%, 4.0%, and 8.0% NaOH at 80°C for 3 h. The dissolved components were subjected to further separation to get eight lignin fractions, which were characterized by gel permeation chromatography, Fourier transform infrared, and sugar analysis. All the lignin fractions had small weight-average molecular weights between 810 and 2580 g/mol. Two typical lignins, L3(prepared with 70% ethanol) and L5(prepared with 70% ethanol containing 1.0% NaOH), were further analyzed using1H,13C NMR and HSQC spectroscopy. Signals from guaiacyl (G), syringyl (S), andp-hydroxyphenyl (H) units observed in aromatic/olefinic region of HSQC spectra indicated that the lignin fromCalamagrostis angustifoliaKom could be classified as “GSH” lignin. In aliphatic-oxygenated region, β-O-4′ together with small amounts of β-5′, β-β′, andp-hydroxycinnamyl alcohol end group were the main interunit linkages observed. Aqueous ethanol, which could avoid the cleavage of ether bonds in lignin at neutral condition, was more effective than water on lignin extraction. [ABSTRACT FROM AUTHOR]

Abstract: A matrix model for age-stage-structured population dynamics of Calamagrostis canescens, a perennial grass species colonizing forest clear-cut areas, was calibrated before from a type of data called ‘identified individuals with unknown parents’ (Logofet, 2008) in order to estimate λ 1, the dominant eigenvalue of the projection matrix. A number of methods were applied to tackle the ‘reproductive uncertainty’ in data, and the output variety contained λ 1 both greater and less than 1 (Logofet, 2008), leaving the estimation uncertain. An ‘adaptation conjecture’ was then proposed that reduced the calibration to a nonlinear constraint maximization problem and provided for a satisfactory outcome. Two reasons have now caused revisiting. First, the maximization technique has been theoretically comprehended. In particular, an existence-uniqueness theorem has been proved that requires the maximizing solution to be reached at a vertex of the polyhedral of constrains. To facilitate searching for the solution in practice, I use the notion of potential-growth indicator and prove R 0 and R 1, the known indicators, to be certain linear functions of the uncertain fertility rates in a general class of projection matrix patterns. To solve a conjugate linear maximization problem under the same constraints as for λ 1 is both theoretically and technically simpler, and this causes a practical benefit from the indication along with calculation. Second, the former uniform (non-specific) estimate of the upper bounds for the status-specific fertility rates has now conceded to the age-stage-specific estimates inferred from a special case study. These more sophisticated constraints produce respectively more accurate calibration, hence a more reliable estimation of λ 1 as the growth potential inherent in the population in a certain environment at a given time. [Copyright &y& Elsevier]

Copyright of Agricultural Sciences / Zemès ukio Mokslai is the property of Lithuanian Academy of Sciences Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The radioecological state of the forest ecosystem in the vicinity of the Ignalina Power Plant prior to decommissioning was analysed with specific emphasis on 137Cs and 90Sr activity concentrations in plant species growing in two reference sampling sites (Tilze and Grikiniskes). In the period of 1996–2008 the mean contamination of plants with 137Cs was from 45 to 119 Bq/kg and with 90Sr – from 3 to 42 Bq/kg. Measured 137Cs TF values for soil-root transfer mainly ranged between 1.0–1.4, except for Calamagrostis arundinacea which had a TF value of 0.1. On average, the 137Cs TF value from root to shoot was 1.7 fold higher than for soil to root transfer. 90Sr TF values (soil-root) were in the range of 1.2–1.8 but for Calluna vulgaris it was 0.2. The mean root to shoot TF value for 90Sr was 7.7 fold higher. These results indicate the higher 90Sr bioavailability than that of 137Cs in the forested area. The Grikiniskes reference site is located nearby the Ignalina NPP, specifically the heated water outlet channel, which results in altered microclimatic conditions. These specific microclimatic conditions result in relationships between 137Cs TF (soil-root) values and pH, moisture and organic matter content in the soil at Grikiniskes which appear to be different to those at the Tilze reference sampling site. [Copyright &y& Elsevier]

Emergent plant species growing in Andean natural wetlands have shown efficient phytoremediation capabilities in wetlands polluted by acid mine drainage. However, the types and amounts of heavy metals accumulated by native plant species are not well understood. In this study, we focused on determining heavy metal concentrations and bioaccumulation factors in Calamagrostis ligulata and Juncus imbricatus. Two acid wetlands located above 3,500 m a.s.l. in Ancash, Peru were assessed. Physico-chemical parameters and heavy metals concentrations in control and experimental plant samples were measured in dry and rainy seasons. Results indicated that C. ligulata and J. imbricatus aerial parts accumulated higher amounts of Fe, Zn, As and Al. Also, bioaccumulation factors revealed notable increases in As, Pb and Al, but less so in Cd, Fe and Zn. On the other hand, physico-chemical parameters of water quality (pH, temperature, dissolved oxygen, sulphides) between inflow and outflow of wetlands indicated significant differences in the presence of metals in comparison with their maximum permissible limits. Both emergent plant species showed an accumulation of heavy metals and thus the ability to recovery of water quality in wetland outflows. [ABSTRACT FROM AUTHOR]

The paper presents the floristic structure of the nodal phytocenoses identified in the vegetation dynamics on the tailing dumps from Căpuş and Aghireş (Cluj County). The incipient vegetation phase of the tailing dumps, regardless of the chemical nature of the stored tailings, is represented by the Tussilago farfara phytocenoses. Within the following phase, when certain Poacee species begin to grown on the tailings, the phytocenoses succession is different. On the acid tailing dumps, one may notice the Calamagrostis epigejos and the Festuca rubra phytocenoses with Agrostis capillaris, while on the neutral or alkaline reaction tailing dumps the Elymus repens and Festuca rupicola phytocenoses are installed. These phytocenoses keep their individuality until the populations of some arbuscular species present in their structure, become prevalent. Within the current study, the Crataegus monogyna and Prunus spinosa phytocenoses end the succession of herbal phytocenoses and enable the growth of forest phytocenoses by the created microclimate. [ABSTRACT FROM AUTHOR]

From May 2005 to September 2006, the potential effects of marsh flooding regimes on the decomposition and nutrient (N, P) dynamics of Calamagrostis angustifolia litter were studied in the typical waterlogged depression in the Sanjiang Plain, Northeast China. The decomposition of C. angustifolia litter was related to four sites with different hydrologic regimes [F1 (perennial flooding, average water depth of 480 days was 40.14 ± 8.93 cm), F2 (perennial flooding 33.27 ± 6.67 cm), F3 (perennial flooding 23.23 ± 5.65 cm) and F4 (seasonal flooding 1.02 ± 1.09 cm)]. Results showed that flooding regimes had important effects on the litter decomposition, the decomposition rates differed among the four sites, in the order of F3 (0.001820d) > F1 (0.001210d) > F2 (0.001040d) > F4 (0.000917d), and the values in the perennial flooding regimes were much higher. Flooding regimes also had significant effects on the N and P dynamics of litter in decomposition process. If the perennial flooding regimes were formed in C. angustifolia wetland due to the changes of precipitation in the future, the litter mass loss would increase 23.28-48.88%, the decomposition rate would increase 13.41-98.47%, and the t would decrease 1.07 yr-4.50 yr. In the perennial flooding regimes, the net N accumulated in some periods, while the net P released at all times. This study also indicated that the changes of N and P content in the litter of the four flooding regimes were probably related to the C/N or C/P ratios in the litter and the N or P availability in the decomposition environment. If the nutrient status of the decomposition environment did not change greatly, the decomposition rates depended on the substrate quality indices of the litter. Conversely, if the nutrient status changed greatly, the decomposition rates might depend on the supply status of nutrient in the decomposition environment. [ABSTRACT FROM AUTHOR]

UV-B radiation and elevated CO2 may impact rhizosphere processes through altered below-ground plant resource allocation and root exudation, changes that may have implications for nutrient acquisition. As nutrients limit plant growth in many habitats, their supply may dictate plant response under elevated CO2. This study investigated UV-B exposure and elevated CO2 effects, including interactions, on plant growth, tissue chemistry and rooting responses relating to P acquisition. The sub-arctic grass Calamagrostis purpurea was subjected to UV-B (0 or 3.04 kJ m−2day−1) and CO2 (ambient 380 or 650 ppmv) treatments in a factorial glasshouse experiment, with sparingly soluble P (0 or 0.152 mg P per plant as FePO4) a further factor. It was hypothesized that UV-B exposure and elevated CO2 would change plant resource allocation, with CO2 mitigating adverse responses to UV-B exposure and aiding P uptake. Plant biomass and morphology, tissue composition and rhizosphere leachate properties were measured. UV-B directly affected chemical composition of shoots and interacted with CO2 to give a greater root biomass. Elevated CO2 altered the composition of both shoots and roots and increased shoot biomass and secondary root length, while leachate pH decreased. Below-ground responses to CO2 did not affect P acquisition although P limitation progressively reduced leachate pH and increased secondary root length. Although direct plant growth, foliar composition and below-ground nutrient acquisition responses were dominated by CO2 treatments, UV-B modified these CO2 responses significantly. These interactions have implications for plant responses to future atmospheric conditions. [ABSTRACT FROM AUTHOR]

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Calamagrostis brachytricha Steud. (feather reed grass) and Festuca glauca Lam. (blue fescue) were grown in mini-lysimeters under four irrigation regimes based on maximum crop evapotranspiration [ETc; 100% ETc (control)], 75% ETc, 50% ETc, or 25% ETc in order to estimate potential water savings in landscape management. Plant responses showed that shoot width, the number of tillers, and shoot dry weights (DWs) in feather reed grass were affected by deficit irrigation, and that there were significant linear correlations between these measurements and irrigation regime. However, in 2006, none of these parameters showed any significant difference between 75% ETc irrigation and the 100% ETc control. In 2007, plant height and the number of tillers gave similar results. There were significant linear correlations between irrigation regime and shoot height, shoot width, and shoot DW in blue fescue plants in 2006 and in 2007, while plants irrigated at 75% ETc showed no significant differences from control 100% ETc plants in both years. To save water and ensure high aesthetic value, a 75% ETc irrigation regime is recommended for both species. Crop coefficients (Kc) were calculated for both species in order to estimate the supplementary irrigation required under historical average conditions (between 1841-1993). Based on these Kc values, historical reference evapotranspiration, and average precipitation, the model indicated that both species required supplementary irrigation during May, June, September, and October. Annual supplementary irrigation was 349.1 mm for feather reed grass and 163.3 mm for blue fescue at 100% ETc. Neither feather reed grass nor blue rescue required supplementary irrigation in July and August, which accounted for 62.4% of annual precipitation. Deficit irrigation at 75% ETc would save 33.1% and 40.3% of annual water use for feather reed grass and blue fescue, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Wetland ecosystems store a large amount of organic carbon (C) in soils, due to the slow decomposition rates of plant litter and soil organic matter. Increased nitrogen (N) availability induced by human activities and global warming may accelerate litter decomposition and affect soil organic C dynamics in wetlands. In the present study, we investigated the effect of N addition on decomposition of Calamagrostis angustifolia litters from freshwater marshes in the Sanjiang Plain of Northeast China under field and laboratory conditions. First, we assessed the changes in initial litter chemical composition and subsequent decomposition following three years of N addition at the rate of 24gNm−2 year−1 under field conditions. Our results showed that N addition increased litter N concentration and decreased C/N ratio, and thus stimulated litter decomposition. Secondly, we examined the effect of increased N availability (0, 25, 50 and 100mgNg−1 litter) on litter decomposition under laboratory conditions. Increased exterior N availability also enhanced microbial respiration and increased litter mass loss under both waterlogging and non-waterlogging conditions. In addition, waterlogging conditions inhibited microbial respiration and suppressed litter mass loss. These findings demonstrated that N addition increased litter decomposition rates through improved litter quality and enhanced microbial activity in freshwater marshes of Northeast China. This implies that increased N availability accelerates litter decomposition rates, and thus may cause substantial losses of soil C and diminish and even reverse the C sink function of wetlands in the Sanjiang Plain of Northeast China. [Copyright &y& Elsevier]

Abstract: Iron cycling in wetlands is important because it plays an important role in interactions among wetland soils/sediments, plants and microorganisms. The seasonal variation of iron (Fe) distributed in two freshwater peatland ecosystems dominated by Calamagrostis angustifolia (CA) and Carex lasiocarpa (CL), was observed in Sanjiang Plain of Northeast China. The compartmentalization of the Fe cycle including storage in the atmosphere, litter, soil, and above- and below ground plant material was determined. The results showed that the Fe input from rain was 0.06gm−2 a−1, and the total Fe mass in the peatland ecosystem was 5.18×103 for CA and 1.40×103 gm−2 for CL. The major Fe pools were soils (98.6% and 97.1% for CA and CL, respectively). The Fe fluxes between each compartment resulted in the increase of the belowground Fe pool and decrease of the litter Fe pool currently both for CA and CL. CL has greater uptake coefficient (0.024) and cycle coefficient (0.034), but smaller use coefficient (0.58) than that of CA (0.02, 0.006, and 0.77, respectively). Peatland conversion for agriculture affected the former natural Fe cycle processes and mass balance to a certain extent in long term, because the Fe assimilated by soybean and rice are less than that of CA and CL, and cannot return to soils from harvesting. Drainage and ditch excavation for agricultural conversion caused considerable Fe loss via aqueous movement, so that Fe was likely lost and transported downstream by these ditch networks. [Copyright &y& Elsevier]

Regeneration of seminatural grasslands are often threatened by the invasion of Calamagrostis epigejos, which can slow down or arrest secondary succession. Here we report the results of a 9-year mowing experiment designed to suppress the spread of C. epigejos in mid-successional grasslands in Hungary. The experimental design consisted of 16 permanent plots of 3 × 3 m. Half of the plots were mowed twice a year (in June and September), the other half was left as control. Vegetation was sampled in 2 × 2 m quadrates before mowing in each year between 2001 and 2009. The effects of mowing were tested using repeated-measure analyses of variance (ANOVA) and Tukey HSD for post hoc tests. Significant decrease of C. epigejos appeared after 2 years of mowing. Species richness increased after 4 years, while diversity after 8 years. By this time the target native species Brachypodium pinnatum become dominant. Similar trends appeared in the control plots during spontaneous succession but at much slower rates. Our results suggest that C. epigejos disappears spontaneously in secondary grassland succession after ca. 40-50 years. However, mowing twice a year can speed up this process by opening a 'colonization window' to the valuable target species. For successful control, mowing should be maintained for approximately 8 years. [ABSTRACT FROM AUTHOR]

Principal component analysis of specimen measurements revealed morphological variation within Chinese Calamagrostis epigeios correlated with differences in geographical distribution. We conducted a morphological examination of specimens from the range of the species, with the goal of developing a treatment for its Chinese members reflecting the global diversity complex. The confusing taxonomy of this complex is clarified with the recognition of three species in China, namely C. epigeios, C. extremiorientalis, and C. macrolepis. Calamagrostis epigeios is an exclusively temperate grass occurring in the northwestern, northern, and northeastern parts of China. It has spikelets 4-7 mm long, glumes equal or subequal, awn arising near the middle of the lemma back, upper leaf surface smooth and with shallow ribs and furrows. Calamagrostis extremiorientalis is a tropical and subtropical grass that occurs in the southwest provinces of China (except Xizang) throughout south central provinces and east to the northeastern parts of China. It is morphologically similar to C. epigeios. However, C. extremiorientalis has the awn arising from the upper one-third of the lemma back, upper leaf surface scabrid because of the presence of short stiff hairs, and with tall ribs and deep furrows. Calamagrostis macrolepis occurs in the northwestern, northern, and northeastern parts of China. It has a robust habit, spikelets 6.5-11 mm long, and glumes unequal, the upper 1-1.5 mm shorter than the lower. New synonyms, descriptions, and citations of representative specimens are provided for each species, along with an identification key. [ABSTRACT FROM AUTHOR]

Sequential treatments of dewaxed Calamagrostis angustifolia Kom with water (60 °C and 90 °C), 70% ethanol, and 70% ethanol containing 0.2%, 1.0%, 2.0%, 4.0%, and 8.0% NaOH at a solid to liquid ratio of 1:25 (g/mL) at 80 ºC for 3 h yielded 36.2% soluble polysaccharides of the dry dewaxed material. The eight polysaccharide fractions obtained were comparatively studied by sugar analysis, GPC, FT-IR, ¹H and 13 C-NMR, and 2D-NMR (HSQC) spectroscopy. The results showed that the water-soluble polysaccharides might contain noticeable amounts of β-D-glucan, as well as some pectic substances and galactoarabinoxylan. 70% ethanol-soluble polysaccharide was mainly arabinogalactan. The five alkali-soluble hemicelluloses were mainly galactoarabinoxylans. The Ara/Xyl and Ara/Gal values of H5-H8 fractions decreased with the increment of NaOH concentration from 1.0% to 8.0%. Meanwhile, the molecular weights had a declining trend from ~60,000 to ~40,000 g/mol. The smaller sized and more branched polysaccharides tended to be extracted in the early stages under milder conditions, and the larger molecular sized and more linear hemicelluloses tended to be isolated under more highly alkaline conditions. [ABSTRACT FROM AUTHOR]

Abstract: A new natural ergopeptine, ergosedmine, was isolated from sclerotia of the ascomycete Claviceps purpurea. Its structure was elucidated by 1D- and 2D-NMR spectroscopy and mass spectrometry as N-(N-lysergyl)-cyclo(isoleucyl-phenylanalyl-prolyl). Partial epimerization of ergosedmine into ergosedminine was evident during purification and in DMSO-d 6. According to common ergot alkaloid nomenclature ergosedmine belongs to the ergoannines, one of the four subgroups of ergopeptines. The sclerotia were obtained from reed feather grass (Calamagrostis arundinacea). Phylogenetic analyses using ITS- and beta-tubulin sequences of pure culture isolates obtained from the C. purpurea sclerotia demonstrated that the ergosedmine-producing strain belongs to the genotype G2, which is associated with wet and shady habitats. [Copyright &y& Elsevier]

Abstract: Soil freeze–thaw cycles in the winter-cold zone can substantially affect soil carbon, nitrogen and phosphorus cycling, and deserve special consideration in wetlands of cold climates. Semi-disturbed soil columns from three natural wetlands (Carex marsh, Carex marshy meadow and Calamagrostis wet grassland) and a soybean field that has been reclaimed from a wetland were exposed to seven freeze–thaw cycles. The freeze–thaw treatments were performed by incubating the soil columns at −10 °C for 1 d and at 5 °C for 7 d. The control columns were incubated at 5 °C for 8 d. After each freeze–thaw cycle, the soil solution was extracted by a solution extractor installed in each soil layer of the soil column, and was analyzed for dissolved organic carbon (DOC), NH4 +–N, NO3 −–N and total dissolved phosphorus (TDP). The results showed that freeze–thaw cycles could increase DOC, NH4 +–N and NO3 −–N concentrations in soil solutions, and decrease TDP concentrations. Moreover, the changes of DOC, NH4 +–N, NO3 −–N and TDP concentrations in soil solutions caused by freeze–thaw cycles were different in various sampling sites and soil layers. The increments of DOC concentrations caused by freeze–thaw cycles were greater in the wetland soil columns than in the soybean field soil columns. The increments of NH4 +–N concentrations caused by freeze–thaw cycles decreased with the increase of soil depth. The depth variation in the increments of NO3 −–N concentrations caused by freeze–thaw cycles in the wetland soil columns was different from that in the soybean field soil columns. The decrements of TDP concentrations caused by freeze–thaw cycles were greater in columns of Carex marsh and Carex marshy meadow than in columns of Calamagrostis wet grassland and the soybean field. The study results provide information on the timing of nutrient release related to freezing and thawing in natural versus agronomic soils, and have implications for the timing of nutrient application in farm fields in relation to water quality protection. [Copyright &y& Elsevier]

Abstract: Anthropogenic activities have increased phosphorus (P) inputs to wetland ecosystems. However, little is known about the effect of P enrichment on soil respiration in these ecosystems. To understand the effect of P enrichment on soil respiration, we conducted a field experiment in Calamagrostis angustifolia-dominated freshwater marshes, the Sanjiang Plain, Northeast China. We investigated soil respiration in the first growing season after P addition at four rates (0, 1.2, 4.8 and 9.6 g P m−2 year−1). In addition, we also examined aboveground biomass, soil labile C fractions (dissolved organic C, DOC; microbial biomass C, MBC; easily oxidizable C, EOC) and enzyme activities (invertase, urease and acid phosphatase activities) following one year of P addition. P addition decreased soil respiration during the growing season. Dissolved organic C in soil pore water increased after P addition at both 5 and 15 cm depths. Moreover, increased P input generally inhibited soil MBC and enzyme activities, and had no effects on aboveground biomass and soil EOC. Our results suggest that, in the short-term, soil respiration declines under P enrichment in C. angustifolia-dominated freshwater marshes of Northeast China, and its extent varies with P addition levels. [Copyright &y& Elsevier]