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Abstract

This account presents comprehensive information on the biology of Phragmites australis (Cav.) Trin. ex Steud. (P. communis Trin.; common reed) that is relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors and to the abiotic environment, plant structure and physiology, phenology, floral and seed characters, herbivores and diseases, as well as history including invasive spread in other regions, and conservation. 2.Phragmites australis is a cosmopolitan species native to the British flora and widespread in lowland habitats throughout, from the Shetland archipelago to southern England. It is widespread throughout Ireland and is native in the Channel Islands. Native populations occur naturally in temperate zones and on every continent except Antarctica. Some populations in Australia and North America have been introduced from elsewhere and have become naturalized, and in North America some of these are known to be invasive where they compete with native local populations of P. australis. Typical habitats in Britain range from shallow still water along waterbody edges to marshlands, salt marshes and drier habitat on slopes up to 470 m above sea level. Additional habitats outside Britain are springs in arid areas (-5 m above sea level) and groundwater seepage points up to 3600 m above sea level. Although it occurs on a wide range of substrates and can tolerate pH from 2.5 to 9.8, in Britain it prefers pH >4.5 and elsewhere it thrives in mildly acidic to mildly basic conditions (pH 5.5–7.5). The species plays a pivotal role in the successional transition from open water to woodland. 3.Phragmites australis is a tall, helophytic, wind-pollinated grass with annual shoots up to 5 m above ground level from an extensive system of rhizomes and stolons. A single silky inflorescence develops at the end of each fertile stem and produces 500–2000 seeds. The plant is highly variable genetically and morphologically. 4.Expansion of established populations is mainly through clonal growth of the horizontal rhizome system and ground-surface stolons, while new populations can establish from rhizomes, stem fragments and seeds. Shoots generally emerge in spring, with timing determined primarily by physiology that is mediated by external conditions (e.g. local climate including frost). 5.Many populations in the British Isles have experienced some decline over the past two decades and there is concern that there might be further losses along the east coast as sea level rises. There has recently also been localized expansions, especially in highly modified habitats: where P. australis reedbeds have been planted as wildlife habitat, rehabilitated mineral- and gravel-beds, and bioremediation filter beds for industrial and transport infrastructure. Native populations outside Britain also demonstrate both types of trends: they are declining in many parts of Western Europe and North America, yet also colonise many disturbed, ruderal habitats (e.g. the edges of agricultural fields and motorways) throughout its native and non-native range and can form ‘weedy’ monodominant populations (e.g. in Australia and China). This article is protected by copyright. All rights reserved.

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... Common reed, Phragmites australis, is a tall (3-5 m) perennial grass that colonizes a wide ecological niche among wetland ecosystems. It can be found in locations ranging from aquatic to terrestrial habitats and on different types of soils with a wide range of organic matter content, pH and nutrient concentrations (Mal & Narine, 2004;Packer et al., 2017). Although native to North America, common reed is now considered as an aggressive exotic invader, thanks to the introduction of a non-native Eurasian genotype (halotype M) that started expanding in North ...
... Flooding, even by a few centimeters or water, reduces the germination rates (Table 52; Baldwin et al., 2010;Coops & van der Velde, 1995;Haslam, 1971;Meng et al., 2016;Yu et al., 2012). Germination is also influenced by temperature, salinity, organic content of the substrate and fungal infection (Haslam, 1972;Packer et al., 2017). Seed germination usually occurs within 2 to 14 days (Galatowitsch et al., 1999;Packer et al., 2017). ...
... Germination is also influenced by temperature, salinity, organic content of the substrate and fungal infection (Haslam, 1972;Packer et al., 2017). Seed germination usually occurs within 2 to 14 days (Galatowitsch et al., 1999;Packer et al., 2017). ...
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Great Lakes coastal wetlands are strongly influenced by their physical environment, particularly by water-level fluctuations that incorporate the effect of large-scale synoptic systems controlling climate (i.e. surface air temperature, precipitation, evaporation, winds, etc). Water levels are therefore frequently described as the primary driver of changes of wetland structure, composition, and distribution, with annual, seasonal, and sub-seasonal fluctuations maintaining wetland vegetation biodiversity and habitat extent. Wetland ecosystems are hence highly vulnerable to the anticipated global warming, as altered lake hydrology can have a significant impact on their ecology. Adverse effects of climate change, which may result in habitat and/or biodiversity loss or increased anthropogenic stressors and expansion of invasive plant species, may lead to a dramatic deterioration of their conservation and functional values. Great Lakes coastal wetlands are strongly influenced by their physical environment, particularly by water-level fluctuations that incorporate the effect of large-scale synoptic systems controlling climate (i.e. surface air temperature, precipitation, evaporation, winds, etc). Water levels are therefore frequently described as the primary driver of changes of wetland structure, composition, and distribution, with annual, seasonal, and sub-seasonal fluctuations maintaining wetland vegetation biodiversity and habitat extent. Wetland ecosystems are hence highly vulnerable to the anticipated global warming, as altered lake hydrology can have a significant impact on their ecology. Adverse effects of climate change, which may result in habitat and/or biodiversity loss or increased anthropogenic stressors and expansion of invasive plant species, may lead to a dramatic deterioration of their conservation and functional values.
... Eutrophication has been identified as a key factor causing the dieback of emergent macrophytes (van der Putten, 1997). However, some researchers found that nutrient enrichment (to a certain extent) could promote the invasion and spread of emergent macrophytes, e.g., reeds, in disturbed ecosystems (Packer et al., 2017;Sciance et al., 2016). These contrasting results suggest the need for a clear understanding of the varying responses and consequences of emergent macrophytes along different degrees of nutrient enrichment, as this is vitally important to the integrated management of aquatic ecosystems. ...
... These levels correspond to the three different trophic states in aquatic ecosystems: mesotrophic, eutrophic and hypertrophic (Brown and Simpson, 2001). Since anthropogenic inputs of nutrients to surface waters mainly occur through various kinds of runoff (Smith et al., 1999) and reeds can absorb nutrients from both water and sediment (Packer et al., 2017), we maintained the set nutrient level in the overlying water through the regular replenishment of tap water and solutions with different nutrient levels. We frequently monitored the N and P concentrations in each tank and accordingly added quantitative nutrients every three days during the first five months and every six days during the last month (for more details, please see the supplemental materials). ...
... Third, a decreasing trend in the SC content in the stem was found as a certain degree of nutrient level increased (Fig. 6), implying that the mechanical resistance (breaking force and strength) and stiffness of stems could be reduced due to nutrient enrichment, thus leading to plant lodging and even community degradation (Lamberti-Raverot and Puijalon, 2012). In addition, leaves with higher nutrient and fibre contents may be preferred by herbivores and could further contribute to these consequences (He and Silliman, 2015;Packer et al., 2017). Last, and most importantly, the response of plants to the nutrient supply could vary with different growth stages and could highly depend on the change in trophic status, suggesting that the times to take management actions and to take nutrient Tables S2 and S3. ...
Article
Human-induced nutrient enrichment is a major stressor in aquatic ecosystems that has resulted in the alteration of ecosystem structures and functions. However, to date, relatively few studies have explored the temporal dynamics of reed biomass and morphological and biochemical traits under different nutrient levels, as well as the phenological pattern. Based on a mesocosm experiment, we monitored the aboveground and underground biomass of reed at the different plant growth stages, along with plant height, ramet and leaf number, leaf length and width, and carbohydrate and nutrient contents in different organs. We found that the significantly different ratio of aboveground to underground biomass was only observed at the late flowering stage between the slight enrichment (S-E) and heavy enrichment (H-E) groups. The start of the fast-growth phase of the aboveground part and underground part was delayed in the higher nutrient enrichment groups. The length of the fast-growth phase of the aboveground part was the same in the medium enrichment (M-E) and H-E groups and longer than that in the S-E group. For the underground part, the longest fast-growth phase was found in the S-E group (105 days), followed by the H-E and M-E groups (46 and 41 days, respectively). As the nutrient level increased, both increased and decreased values were observed for the 29 monitored morphological and biochemical traits, and the magnitude changed with the different growth stages. Moreover, different degrees of nutrient enrichment could differentially enhance or weaken the relationships among the groups between total biomass and the integrated morphological trait, between structural carbohydrate (SC) and total nitrogen (TN) contents, between total organic carbon (TOC) and TN, between total phosphorus (TP) contents, between TOC and SC contents. Our findings highlight a crucial contribution of ambient nutrient supply to temporal variation in plant biomass and phenological, morphological and biochemical traits.
... The presence of well-developed aerenchyma facilitates the exchange of gases between the plant and the external environment, but also improves the supply of plants with air, in which the water and wetland environment is generally poor (Engloner 2009). In addition to the above, an important characteristic of these plants is vegetative propagation (by rhizome), which allows these plants to spread very successfully (Packer et al. 2017;Cuda et al. 2021). The growth and development of certain macrophyte species depend on a number of factors. ...
... Thus, water depth, i.e., water regime, water chemical composition, pH and salinity are important factors influencing their abundance and biomass. Moreover, the composition and properties of sediments and substrates also significantly affect their growth and development (Packer et al. 2017;Cuda et al. 2021). Macrophytes are of great importance because of their huge organic production (biomass) and the creation of plant cover (vegetation), which directly reflects on the general functioning of the biosphere. ...
... Thus, photosynthesis is the primary process by which the production of organic matter and oxygen, which are a necessary prerequisite for life on Earth, is achieved (Bidlack and Janski 2011). Reed (Phragmites australis), too, as a perennial plant which rhizomes can survive for approximately 10 years (Roberts 2000), is specific because by living in certain growing conditions, i.e., appropriate temperature and humidity with enough nutrients, it forms huge biomass (Alling et al. 2004;Packer et al. 2017). ...
Article
In this paper, aboveground biomass and basic nutrients removal, nitrogen (N) and phosphorus (P), was analyzed by the use of reed as the main component of Constructed Wetland System (CWS) "Gložan". In almost ideal conditions of temperate continental climate, with favorable substrate humidity, due to the constant inflow of municipal wastewater, reed populations reach a high density, on average 217 ind/m2. The reed produces significant aboveground biomass, fresh weight (FW) of 144.21 g/plant and dry weight (DW) of 77.04 g/plant, with the largest share being per tree (87.49 g FW/plant, 48.17 g DW/plant), then leaf (49.45 g FW/plant, 24.89 g DW/plant) and the smallest inflorescence (7.27 g FW/plant, 3.99 g DW/plant). The results obtained in this way indicate that the largest amount of nitrogen was removed by leaves, then by stems and, the smallest by inflorescences, 181.07 g/m2, 97.73 g/m2, 23.41 g/m2, respectively. Thus, an average of 302.21 g/m2 of nitrogen was removed by the entire aboveground part of the reed. Also, the largest amount of phosphorus was removed by leaves, then by stems, and the smallest by inflorescences, 5.72 g/m2, 4.82 g/m2 and 2.57 g/m2, respectively, while the entire aboveground part of the reed is on average about 13.11 g/m2.
... (Common Reed, Poaceae) is a perennial helophyte species distributed worldwide with the exception of Antarctica. This species is native to Europe and naturally occurs in temperate climates, but some genotypes were introduced to North America and became invasive (Packer et al., 2017). Phragmites australis can form underground stolons and long rhizomes, and can reproduce both vegetatively and by seeds (Packer et al., 2017). ...
... This species is native to Europe and naturally occurs in temperate climates, but some genotypes were introduced to North America and became invasive (Packer et al., 2017). Phragmites australis can form underground stolons and long rhizomes, and can reproduce both vegetatively and by seeds (Packer et al., 2017). Seed production can vary depending on the origin of the population (e.g., British Islands: 500-2000 seeds/inflorescence per ramet (Packer et al., 2017); Canada: 350-800 seeds/inflorescence (Maheu-Giroux and De Blois, 2007). ...
... Phragmites australis can form underground stolons and long rhizomes, and can reproduce both vegetatively and by seeds (Packer et al., 2017). Seed production can vary depending on the origin of the population (e.g., British Islands: 500-2000 seeds/inflorescence per ramet (Packer et al., 2017); Canada: 350-800 seeds/inflorescence (Maheu-Giroux and De Blois, 2007). ...
Article
Seed dispersal plays an important role in population dynamics in agricultural ecosystems, but the effects of surrounding vegetation height on seed dispersal and population connectivity on the landscape scale have rarely been studied. Understanding the effects of surrounding vegetation height on seed dispersal will provide important information for land-use management in agricultural landscapes to prevent the spread of undesired weeds or enhance functional connectivity. We used two model species, Phragmites australis and Typha latifolia, growing in small natural ponds known as kettle holes, in an agricultural landscape to evaluate the effects of surrounding vegetation height on wind dispersal and population connectivity between kettle holes. Seed dispersal distance and the probability of long-distance dispersal (LDD) were simulated with the mechanistic WALD model under three scenarios of "low", "dynamic" and "high" surrounding vegetation height. Connectivity between the origin and target kettle holes was quantified with a connectivity index adapted from Hanski and Thomas (1994). Our results show that mean seed dispersal distance decreases with the height of surrounding matrix vegetation, but the probability of long-distance dispersal (LDD) increases with vegetation height. This indicates an important vegetation-based trade-off between mean dispersal distance and LDD, which has an impact on connectivity. Matrix vegetation height has a negative effect on mean seed dispersal distance but a positive effect on the probability of LDD. This positive effect and its impact on connectivity provide novel insights into landscape level (meta-)population and community dynamics-a change in matrix vegetation height by land-use or climatic changes could strongly affect the spread and connectivity of wind-dispersed plants. The opposite effect of vegetation height on mean seed dispersal distance and the probability of LDD should therefore be considered in management and analyses of future land-use and climate change effects.
... from the Poaceae family. Phragmites australis is a cosmopolitan species that naturally occurs on all continents except Antarctica (Packer et al. 2017); the populations of European origin, classified as P. australis subsp. australis, invaded wetlands in North America, leading to alteration of wetland communities and displacement of native American populations, P. australis subsp. ...
... australis, invaded wetlands in North America, leading to alteration of wetland communities and displacement of native American populations, P. australis subsp. americanus (Chambers et al. 1999, Saltonstall 2002, Meyerson et al. 2009, Packer et al. 2017. Phragmites australis is a tall helophytic perennial grass that often dominates both aboveground, where culms grow up to~4 m, and belowground, where rhizomes form extensive and dense mats (Haslam 1972, Pyšek et al. 2019. ...
... Phragmites australis is a tall helophytic perennial grass that often dominates both aboveground, where culms grow up to~4 m, and belowground, where rhizomes form extensive and dense mats (Haslam 1972, Pyšek et al. 2019. It reproduces and spreads both generatively by seed and vegetatively by stolons and rhizomes (Haslam 1972, Packer et al. 2017. The latter mode of reproduction was thought to prevail (Haslam 1972, Hudon et al. 2005, but the importance of seed dispersal has also been highlighted (Belzile et al. 2010, McCormick et al. 2010. ...
Article
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Regeneration from vegetative fragments is common in plants that occur in disturbed and wet habitats but quantitative data comparing regeneration of different plant parts under various environmental conditions are still scarce. Phragmites australis is a dominant and a keystone wetland species that is widespread all around the world. It spreads both vegetatively by rhizomes and stolons and generatively by seed. Detached vegetative fragments of culms and rhizomes can support local regeneration after disturbance and spread populations over considerable distances when transported with water, soil and other means. In P. australis, there is no information on culm regeneration and how regeneration differs between the clones of different origin and what is the effect of the environment. Here we studied the regeneration of P. australis from culm and rhizome fragments over six weeks (mid-June to late July 2017) in a common-garden pot experiment. To simulate various scenarios that can happen in nature, we placed cuttings of culms and rhizomes (representing propagules) in 6-l pots in water, on the sand surface, and buried them 5 cm deep in the sand. We included 19 distinct clones representing populations from three phylogeographic groups (North American invasive, North American native, and European). We tested the effect of phylogeo-graphic group, plant part (culm, rhizome), environment (water, surface, buried), ploidy and genome size on clone regeneration using generalized mixed-effect models. A higher percentage of culms than rhizomes regenerated (69% vs. 37%, respectively). Regeneration was better in fragments placed in water than in those buried and on the sand surface (65%, 50%, and 44%, respectively). Although we found considerable differences in regeneration among particular Phragmites populations (ranging from 31% in one of the North American native tetraploids to 90% in a North American invasive octoploid), the effect of the phylogeographic group was not statistically significant. However, phylogeographic group interacted with plant part-culms of the North American invasive populations regenerated better than those of North American natives, while rhizomes did not differ among phylogeographic groups. This difference was most pronounced in the sand-surface treatment. Rhizome fragments produced greater culm-and root biomass than culm fragments and North-American native clones produced the least new biomass of all groups. Lastly, rhizomes regenerated more slowly than culms (16 and 13 days to produce new shoots, respectively), and regeneration was fastest in water. Our results point to a great regeneration ability of culm fragments , which can cope with a wide range of environmental conditions and grow rapidly to produce new plants. We suggest this played an important role in spreading the invasive populations in North America, whose culm fragments regenerated better than those of native populations. Culms of invasive populations did not require to be permanently exposed to water for regenera-tion, which may have also facilitated their spread to drier habitats and their niche expansion beyond wetlands.
... Description du roseau Phragmites australis [10] leur chute, de rester à la surface de l'eau pendant plusieurs mois et de circuler afin de coloniser un autre endroit. Chaque inflorescence produit jusqu'à 1 000 graines [8] dont la fertilité est comprise entre 0,1 et 59,6 % [9]. ...
... En effet, le réseau de rhizomes souterrains permet d'apporter tous les nutriments pour la production de nouvelles pousses. Les stolons 4 permettent également à la plante de se multiplier [10]. ...
... Au fil des mois, ces composés étant plus facilement décomposés, ils laissent la place à la cellulose, à l'hémicellulose et à la lignine (Figure 7). Le roseau sèche à l'arrivée de l'automne avec une composition pouvant varier pendant l'hiver et avant récolte conduisant à une augmentation de la quantité de lignine [10]. ...
Thesis
L'utilisation de fibres végétales, tant dans le domaine de la plasturgie que dans celui du bâtiment, permet de réduire les émissions de gaz à effet de serre et par conséquent l'impact environnemental de l’Homme. L'intérêt envers les bio-composites utilisant des fibres végétales telles que le chanvre, le bois, le lin mais également le roseau miscanthus ne cesse d'augmenter. Il n'existe, à l'heure actuelle, que très peu de travaux s’intéressant au roseau phragmites australis. Pourtant, n'utilisant pas de surfaces cultivées, cette plante invasive est indépendante des enjeux agricoles et ne demande aucun intrant chimique. La récolte du roseau s'inscrit donc dans une démarche de gestion des zones humides tout en valorisant un matériau aux multiples propriétés. Les travaux de cette thèse sont consacrés à la caractérisation du matériau brut phragmites australis et à l’étude de son éligibilité comme matériau en substitution de trois matériaux de référence, le bois, le miscanthus et la chènevotte, largement utilisés comme renforts en plasturgie et en éco-construction. Des formulations de composites utilisant deux matrices polymères (polypropylène et polybutylène succinate) à différents taux de charges végétales et d’agent compatibilisant ont été caractérisées d’un point de vue de leurs propriétés mécaniques par des essais de traction, flexion et choc Charpy. Le vieillissement à l’eau de ces composites a également été étudié et corrélé au caractère hydrophobe du roseau. Pour le volet construction, des formulations à base de roseaux de différentes origines et utilisant différents liants (chaux aérienne, plâtre et terre) ont été testées en compression et avec des mesures de conductivité thermique afin d’évaluer le comportement du roseau en tant que matériau d’usage pour le bâtiment
... Ultimately reed warbler's breeding range is limited by habitat: relatively little of the Earth's surface is covered in reedbed. Next, reed warbler's breeding range is probably limited by dispersal: reedbeds are found on every continent except Antarctica (Packer et al. 2017 site-based studies for reed warbler (e.g. Brown & Davies 1949;Catchpole 1974). I thus attempt to present the variation in findings between sites, but this is not always possible where specific aspects of reed warbler ecology have been researched at relatively few sites. ...
... Although reedbeds are sparser in the north and west of Britain (Packer et al. 2017 One of the best-known effects of climate change on our biosphere is that of advanced spring phenology in birds (e.g. Both et al. 2004). ...
... Reed warblers largely breed in reedbed, and occasionally in other wetland habitats and crops. In Britain, reed exists on a wide variety of substrates, from the high water mark to 470 m above sea level and is catholic in its tolerated hydroperiods and pH values (Packer et al. 2017). Reedbed, as large stands of reed suitable for breeding reed warblers, occupies a narrower range of conditions but may still vary importantly in habitat quality for reed warbler across Britain. ...
... Its habitat includes climate zones ranging from cool to tropical and arid. For all European countries, this species is recognized as native (Packer et al., 2017). P. australis demonstrates high plasticity and the ability to adapt to a broad range of environmental conditions (Milke et al., 2020), especially in the context of potentially toxic elements (PTEs), which are mostly represented by metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sn, V, and Zn), metalloids (As, Sb), and nonmetals (Se) (Antoniadis et al., 2021;Shaheen et al., 2019). ...
... P. australis demonstrates high plasticity and the ability to adapt to a broad range of environmental conditions (Milke et al., 2020), especially in the context of potentially toxic elements (PTEs), which are mostly represented by metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sn, V, and Zn), metalloids (As, Sb), and nonmetals (Se) (Antoniadis et al., 2021;Shaheen et al., 2019). Based on the data provided by Packer et al. (2017), P. australis occurs in its native range globally under the following substrate conditions (in min-max ranges): N (0-2430 mg/kg), P (180-6890 mg/kg), Cd (<44 mg/kg), Pb (<15,900 mg/kg), Cu (<275 mg/kg d.w.), Cr (<218 mg/kg d.w.), Zn (<11,000 mg/kg d.w.), and Ni (<81.6 mg/kg). In Europe, the pH of the solid substrate in which P. australis grows is generally 7; however, populations thrive when the pH is between 5.5 and 7.5. ...
... while the organic matter content was on average 10.8%). Despite the wide pH tolerance (between 2.5 and 9.8 for the most extreme conditions) of P. australis (Packer et al., 2017), Shaltout et al. (2006) emphasized that "the clones growing at a particular site are probably well adapted to those site conditions and possibly do not thrive in other conditions". Thus, the choice of proper P. australis seedling clones is quite important in planning the treatment processes of contaminated sites. ...
Article
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The study presents results from 6 months of phytoremediation of sediments dredged from three urban retention tanks carried out in a mesocosm setup with the use of P. australis. Two kinds of P. australis seedlings were considered: seedlings originating from natural (uncontaminated - Suncont) and anthropogenically changed environments (contaminated – Scont); this distinction was reflected in the baseline concentrations of trace metals inside their tissues. The potentially toxic elements (PTEs) considered in this study were as follows: Zn, Cu, Cd, Ni, Cr, and Pb. The aim of the study was to compare the uptake, accumulation, and translocation properties of seedlings with different initial trace metal contents. The PTE concentrations were analyzed in sediments as well as in belowground and aboveground parts of plants in the middle (3rd month) and at the end of the investigation period using inductively coupled plasma mass spectrometry (ICP-MS), and the accumulation of PTEs in plant tissues was calculated. Phytoextraction efficiency was evaluated using the bioconcentration factor (BF) and translocation factor (TF). Plant morphology was assessed with scanning electron microscopy (SEM) to document plant stress due to PTE exposure. The results of our study indicated that P. australis seedlings originating from sites differing in the initial trace metal content exhibited different behavior when grown on sediments dredged from urban retention tanks. Suncont seedlings with low initial metal contents tended to adapt to the dredged sediments and showed phytoextraction ability, while Scont seedlings originating from sites with initial high contents of trace metals acted as phytoexcluders and tended to release PTEs from their tissues into the sediments. The morphological and structural effects caused by metal toxicity were observed in growth limitation, root tissue disturbance, root hair number decrease, and structural alterations in the epidermis and endodermis. Therefore, the Suncont seedlings presented better properties and adaptability for phytoremediation purposes.
... ex Steud. (common reed, Poaceae; hereafter Phragmites) (Packer et al., 2017) and Typha domingensis Pers. (cumbungi or southern cattail, Typhaceae; hereafter Typha) (Ciotir & Freeland, 2016), have broad ecological amplitudes and can be highly productive in human-modified habitats (Rodwell, 1998). ...
... (cumbungi or southern cattail, Typhaceae; hereafter Typha) (Ciotir & Freeland, 2016), have broad ecological amplitudes and can be highly productive in human-modified habitats (Rodwell, 1998). Phragmites australis is recognised as a particularly problematic species with a complex genetic structure and global distribution of distinct haplotypes (Canavan et al., 2018;Packer et al., 2017), and some haplotypes of T. domingensis have been introduced beyond their native range (Ciotir & Freeland, 2016). Both Phragmites and Typha are most productive and sometimes form monodominant stands in disturbed, fertile and flooded habitats (Davis, 1991;Osland et al., 2011;Saltonstall & Stevenson, 2007), from desert oases (Lewis & Packer, 2020) and semi-arid rivers (Deegan et al., 2012) to tropical wetlands (Newman et al., 1996). ...
... Just as a change in the type of disturbance regime can be a stronger predictor of plant invasiveness than disturbance per se (Hobbs & Huenneke, 1992;Moles et al., 2012), changes in disturbance frequency may strongly influence biomass (Wang et al., 2016) and its allocation between organs. As the depth, movement, and nutrient levels of water strongly influence Phragmites (Boar et al., 1989;Packer et al., 2017;Rodwell, 1998), identifying the mechanisms underlying the effect of nutrient enrichment and/or fluctuating hydrological regimes may help to predict belowground productivity. ...
Article
Plant communities within many of the world’s waterways are losing diversity where flows are stabilised for security and enriched from land-use intensification. Understanding the phenotypic plasticity of plant species that protect and/or store their below-ground biomass during floods may help to promote them if problematic, overabundant species – like Phragmites australis and Typha domingensis – are less plastic. To investigate mechanisms underlying the plasticity of two cosmopolitan (Phragmites, Typha) and two endemic (Cycnogeton procerum, Cyperus gymnocaulos) macrophytes in response to disturbance (fluctuating hydrological regimes) across a nutrient gradient, we analysed historical data from pond experiments with single-species pots. Our analyses showed fluctuating water levels in nutrient-enriched conditions reduced total biomass in all species, with 65% and 46% reduction in Phragmites and Typha respectively. Contrary to expectations, only Cycnogeton allocated a higher proportion of biomass to protect (root) and store (rhizome) resources in fluctuating water levels and nutrient-enriched conditions (45% versus 23% in stable regime), and was the most plastic by allocating 75% more biomass to belowground in the least favourable conditions. Our results indicate that removing impediments to stochastic flooding disturbance could benefit some endemic species while reducing the productivity of overabundant Phragmites and Typha in environments enriched by human activity.
... The common reed is successful in habitats with stable or regular hydrology [29]. The higher variability in the measured parameters for samples from the lake reed stand in comparison to those from the riparian reed stand was a consequence of extreme water level fluctuations. ...
... Hayball and Pearce [30] reported that in deep water, the common reed developed lower numbers of shoots, while a decrease in the water level increased the plant density and leaf numbers, which positively affected the leaf area index and consequently affected the productivity [15]. A high density of reed culms causes self-shading, which decreases the flowering rate and increases the leaf to stem mass ratio [29]. On the other hand, culm height and density significantly contribute to the competitive success of the common reed in terms of the shading out of other plant competitors in the habitat [31]. ...
... Irregular and strong water movements are usually the consequence of extreme water level fluctuations, like waves or currents, and may negatively affect the competitiveness of the common reed [29]. Water movement represents a physical force that can break reed culms and prevents the passive and humidity-induced aeration of the rhizome system at higher water levels, which also occurs via dead stems [16,42]. ...
Article
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Lake Cerknica is an intermittent wetland ecosystem with extreme water level fluctuations. It hosts extensive reed stands that have colonized different habitat types. Two different stands were compared: a lake stand not directly influenced by the intermittent River Stržen and a riparian stand near River Stržen. Reed productivity (growth and assimilate allocation) was monitored for these reed stand types over 13 years (2007-2019), and this measurement was compared to monthly water levels and air temperatures. Reeds from the lake reed stand were significantly shorter with a lower shoot density, overall biomass production, and ratio of flowering plants. A correlation analysis revealed stronger and more numerous significant correlations between environmental and reed productivity parameters for the lake reed stand compared to the riparian reed stand. The variabilities of the growth and assimilate allocation parameters in the lake reed stand were both mostly explained by the combined water levels for June and July, which explained 47% and 52% of the variability, respectively. The most influential temperatures were in May, which explained 29% and 19% of the variability of growth and assimilate allocation parameters, respectively. For the riparian reed stand, water levels and temperatures out of the vegetation season appeared more important. Therefore, habitats with permanent water are more suitable for reeds than those with fluctuating water. However, fluctuating water conditions are expected to become more common due to climate change.
... The Switzerland literature ranked first in terms of impact (centrality = 0.66), which indicates that its findings are globally worthy of being referenced by scholars. The literature proposed CWs combined with phytoremediation techniques [36,37], as well as a macrostudy of CWs in water management [10,38,39]. Figure 4 shows a collaboration-network map of the authors created with CiteSpace software. ...
... The Switzerland literature ranked first in terms of impact (centrality = 0.66), which indicates that its findings are globally worthy of being referenced by scholars. The literature proposed CWs combined with phytoremediation techniques [36,37], as well as a macrostudy of CWs in water management [10,38,39]. ...
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Water management is a crucial resource conservation challenge that mankind faces, and encouraging the creation of manmade wetlands with the goal of achieving long-term water management is the key to long-term urban development. To summarise and analyse the status of the research on the relationship between water management and constructed wetlands, this paper makes use of the advantages of the bibliometric visualization of CiteSpace to generate country/region maps and author-collaboration maps, and to analyse research hotspots and research dynamics by using keywords and literature co-citations based on 1248 pieces of related literature in the core collection in the Web of Science (WoS) database. The existing research shows that the research content and methods in the field of constructed-wetland and water-management research are constantly being enriched and deepened, including the research methods frequently used in constructed wetlands in water management and in the research content under concern, the functions and roles of constructed wetlands, the relevant measurement indicators of the purification impact of constructed wetlands on water bodies, and the types of water bodies treated by constructed wetlands in water management. We summarise the impact pathways of constructed wetlands on water management, as well as the impact factors of constructed wetlands under water-management objectives, by analysing the future concerns in the research field to provide references for research.
... In Europe, the pH of the solid substrate on which P. australis grows is generally seven but plants also develop well in a pH range of 5.5 to 7.5 [64]. It has been shown that P. australis can tolerate a wide pH range even between 2.5 and 9.8 [65]. C. demersum thrives in neutral and alkaline environments, but a pH that is too high can lead to stress in plants. ...
... As reported in the literature, the toxic concentration of Pb for different plants ranges from 0.01 mg/g to 0.1 mg/g [84]. P. australis, under natural conditions, grows on substrates where the heavy metal content does not exceed: Cd (<0.04 mg/g), Pb (<15.9 mg/g), Cu (<0.275 mg/g), Cr (<0.218 mg/g) and Ni (<0.082 mg/g) [65]. Common reed has the ability to take up large amounts of micronutrients due to its extensive tissue system and defence mechanisms [64]. ...
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One of the key problems associated with the functioning of landfills is the generation of leachate. In order to reduce their negative impact on the environment, various treatment technologies are applied. Among them, solutions based on the use of phytotechnology deserve special attention. The aim of this study was to evaluate the impact of landfill leachate on the content of micro- and macroelements in plant material. The research was carried out in four municipal waste landfills located in Poland. Emergent macrophytes (P. australis) and submergent macrophytes (C. demersum) were used in this research. The migration and distribution of pollutants reaching the roots and shoots of P. australis from water solutions were also studied. The concentrations of heavy metals in the studied plants were low in all analysed cases. Higher metal contents could often be observed in roots rather than in shoots, but these differences were insignificant. The chemical composition of the studied plant samples was primarily related to the source of origin of the treated leachate (landfill), as clearly demonstrated by cluster analysis. In the conducted studies, no important differences were noted in the accumulation of the studied components between submergent plants (C. demersum) and emergent macrophytes (P. australis).
... Regarding the presence of individual species of interest, we anticipated a decrease of Phragmites australis over time if restoration measures were successful, as Phragmites indicates eutrophic and weakly basic to weakly acidic conditions (Landolt et al. 2010, Packer et al. 2017, i.e., conditions not found in intact raised bogs (Vitt 2006). Furthermore, we expected to observe an initial increase of species typical of transitional bogs and species known to benefit from restoration measures, such as Sphagnum palustre and especially S. recurvum aggr. ...
... This might also be the case in the Hagenmoos. As Phragmites can form very long roots (Marks et al. 1994, Packer et al. 2017, our results may also indicate that this species experiences site conditions different from those of the species found in its immediate proximity. The development of Phragmites in the Hagenmoos bog should be further monitored, as it may shade typical bog species (e.g. ...
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Raised bogs as huge carbon stocks are of worldwide importance, but they have been severely decreased and degraded globally. To stop this development, restoration measures are being carried out in many countries. The recovery of raised bogs is, however, slow and the success of restoration projects is uncertain. Long-term monitoring is thus needed. The Hagenmoos raised bog in the Swiss Plateau was restored by logging within former peat-cutting pits and by blocking drainage pathways. The vegetation in the bog was recorded 3 times within 72 permanent plots: immediately before, 10 years after and 30 years after restoration. Based on these vegetation surveys, changes in habitat conditions (ecological indicator values) and in species richness and single species were analysed. Overall, the restoration measures proved to be successful. Mean indicator values for light and moisture both increased over time. The increase of these indicators was strongest during the first 10 years after restoration and weakened afterwards. Within former peat-cutting pits, both indicator values reached values from a reference dataset composed of 21 plots from Swiss raised bogs representing typical bog communities. However, 30 years after restoration, mean light and moisture indicator values were still significantly lower outside former peat-cutting pits than within them, indicating a need for further restoration measures.
... (Common Reed, Poaceae) is a cosmopolitan grass species occurring mainly in wetlands, with native populations distributed in temperate zones on every continent except Antarctica. Some genotypes introduced from Europe have become invasive in North America (Saltonstall et al. 2007;Packer et al. 2017). This species is a perennial helophyte with an extensive system of stout, underground stolons and long rhizomes expanding more than 0.25 m year -1 and considered "a fast clonal spreader" as well. ...
... This species is a perennial helophyte with an extensive system of stout, underground stolons and long rhizomes expanding more than 0.25 m year -1 and considered "a fast clonal spreader" as well. P. australis reproduces both vegetatively and by seeds (Packer et al. 2017). The species is polyploid with diploid, triploid, tetraploid, and octaploid individuals (n = 12), with tetraploids being most common worldwide (Kühn et al. 2004;Saltonstall et al. 2007). ...
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In plants, long-distance dispersal is both attenuated and directed by specific movement vectors, including animals, wind, and/or water. Hence, movement vectors partly shape metapopulation genetic patterns that are, however, also influenced by other life-history traits such as clonal growth. We studied the relationship between area, isolation, plant-species richness, reproduction, and dispersal mechanisms with genetic diversity and divergence in 4 widespread wetland plant-species in a total of 20 island-like kettle-hole habitats surrounded by an intensive agricultural landscape. Our results showed that genetic parameters reflect the reproduction strategies with the highest genetic diversity being observed in the non-clonal, outcrossing Oenanthe aquatica compared to the clonal Lycopus europaeus, Typha latifolia, and Phragmites australis. Lycopus showed a positive relationship between genetic diversity and kettle-hole area, but a negative relationship with the number of neighboring kettle holes (less isolation). Genetic diversity increased with plant-species richness in the clonal species Phragmites and Lycopus; while it decreased in the non-clonal Oenanthe. Finally, genetic divergence and, therefore, connectivity differed between alternative dispersal strategies, where wind-dispersed Typha and Phragmites had a higher gene flow between the analyzed kettle holes compared with the insect-pollinated, hydrochorous Lycopus and Oenanthe. Our study provides information on genetic patterns related to reproduction and dispersal mechanisms of 4 common wetland species contributing to the understanding of the functioning of plant metacommunities occurring in kettle holes embedded in agricultural landscapes.
... However, there has been a growing awareness of the importance of P. australis for invertebrates and its contribution to biodiversity in wetland habitats (Kirby 2001). In Britain, 108 mainly phytophagous invertebrate species, from a wide range of orders, are known to be associated with the plant (Packer et al. 2017). However, this figure does not include the parasitic Hymenoptera. ...
... Noyes (2019) lists 58 species of Chalcidoidea (Hymenoptera), worldwide, that are parasitic on egg, larval, pupal or adult stages of invertebrates associated with P. australis but it is certain there are many more to be discovered. One of the species listed by Packer et al. (2017) is Giraudiella inclusa (Frauenfeld) (Diptera: Cecidomyiidae). This species induces galls inside the stems of P. australis. ...
Article
Giraudiella inclusa (Frauenfeld) (Diptera: Cecidomyiidae) induces galls in stems of Phragmites australis in wetland habitats. The parasitoid community (Hymenoptera: Chalcidoidea) associated with the galls was studied in Kent, England. Nine species of Chalcidoidea were identified. This rich community forms an important part of the biodiversity of stands of P. australis .
... The reed plant has a creeping rhizome system, a modified, subterranean stem that produces roots and shoots from its nodes. The shoots grow into long upright basal stems which reach 1-3 meters in height, sometimes up to 7 meters, with temperature, environment, and nutrient levels impacting productivity (Packer, 2017). The stems are grouped in stands and are covered with long leaves and topped with 'feathers' scientifically known as the panicle; the flowering part which produces seeds. ...
... These contradictory ndings may be owing to the high elevation of the enclosure coastal wetland examined in the present study, which was unsuitable for S. alterni ora growth, but conducive to P. communis growth. Similar results have also been reported by Packer et al. (2017) and Chen et al. (2005), who indicated that the best elevation for P. communis is about 4 m, while that for S. alterni ora is about 2.5 m. ...
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Although tidal wetlands in the Yangtze River Estuary are important carbon sinks, some are modified by different engineering measures to protect beaches, prevent corrosion, and promote tidal flat siltation. Nevertheless, some basic characteristics of these modified wetlands are still retained for their ecological service functions. Elucidation of the differences in carbon sink capacity and carbon storage of different types of modified tidal wetlands and the underlying reasons can provide theoretical guidance and a scientific basis for the protection and rational utilization of tidal wetlands, so as to maintain and enhance their carbon sink capacity. In this study, five typical modified tidal wetlands in the Yangtze River Estuary, namely, enclosure coastal wetland with Spartina alterniflora (ECS), enclosure coastal wetland with Phragmites communis (ECP), siltation coastal wetland with S. alterniflora (SCS), rock rip-rap riverside wetland with P. communis (RRP), and reclamation riverside wetland with P. communis (ReRP), were selected as study zones, and their carbon sink capacity and carbon storage were evaluated by analyzing soil organic carbon density, plant carbon fixation, and soil CO 2 emissions. The possible reasons for the differences among these modified wetlands were considered based on elevation, average waterlogging time, tidal salt content, and vegetation types. The results showed that all the modified wetlands were net carbon sinks, with SCS exhibiting the highest carbon sink capacity (8.34–8.52 kg CO 2 m − 2 year − 1 ), reaching the level of natural wetland, owing to its higher plant biomass and lower soil respiration intensity, followed by ReRP (2.68–3.15 kg CO 2 m − 2 year − 1 ), ECP (2.56–3.37 kg CO 2 m − 2 year − 1 ), RRP (2.94–3.04 kg CO 2 m − 2 year − 1 ), and ECS (1.24–1.86 kg CO 2 m − 2 year − 1 ). ReRP (26.89–27.82 kg CO 2 m − 2 ) with long carbon accumulation history and SCS (24.57–28.6 kg CO 2 m − 2 ) with high annual carbon sink capacity presented higher carbon storage (< 40 cm), followed by RRP (22.52–24.97 kg CO 2 m − 2 ), ECP (16.14–18.18 kg CO 2 m − 2 ), and ECS (5.74–6.70 kg CO 2 m − 2 ). The difference in waterlogging time caused by diverse elevation, salinity, and vegetation types significantly affected soil respiration and plant carbon fixation, thus impacting CO 2 emission and carbon sink capacity of different modified tidal wetlands.
... Its habitat includes climate zones ranging from cool to tropical and arid. For all European countries, this species is recognized as native (Packer et al., 2017). It has been planted extensively in constructed wetlands for the remediation of wastewater and effluents (Anning et al., 2013). ...
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Environmentally sustainable remediation is needed to protect freshwater resources which are deteriorating due to severe industrial, mining, and agricultural activities. Treatment by floating wetlands could be a sustainable solution to remediate water bodies. The study aimed to examine the effects of Cd on Phragmites australis and Iris pseudacorus growth (height, biomass, root length and chlorophyll contents), anatomy, Cd accumulation in their biomass and their ability to remove Cd, N and P. Seedlings of both plants were grown in a greenhouse for 50 days in artificially prepared stormwater amended with Cd, N, and P. The treatments were: control (Cd _0), Cd_1, Cd_2, and Cd_4 mg L − 1. N and P contents were 4 mg L − 1 and 1.8 mg L − 1 , respectively. In the case of P. australis, the maximum plant height, root length, and total dry biomass production was increased in medium dose (Cd_2) treatment while the chlorophyll index (CCI) increased in high dose (Cd_4) treatment as compared to all treatments. For I. pseudacorus, the maximum plant height and total dry biomass production, root length and CCI values were improved in low dose (Cd_1) and high dose (Cd_4) treatments, respectively among all treatments. Results showed that P. australis accumulated 10.94-1821.59 μg ⋅ (0.05 m 2) − 1 in roots and 2.45-334.65 μg ⋅ (0.05 m 2) − 1 in shoots under Cd_0, Cd_1 and Cd_4 treatments. I. pseudacorus accumulated the highest Cd in roots up to 5.84-4900 μg ⋅ (0.05 m 2) − 1 and 3.40-609 μg ⋅ (0.05 m 2) − 1 in shoots under Cd_0, Cd_1 and Cd_4 treatments. The translocation factor was observed as <1 and the bioconcentration factor >1 for both species, which indicates their phytostabilization potential. Results demonstrate that P. australis and I. pseudacorus are suitable for use in floating wetlands to remediate contaminated sites.
... Phragmites australis (common reed) is a tall-stature emergent wetland plant widely distributed all over the globe. This species is highly variable in morphology and genetics with extensive stolons and rhizomes (Packer et al. 2017). Clonal growth promotes its thriving and bene ts its invasion in wetlands. ...
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Background and aims The introduced lineage of Phragmites australis (haplotype M) in North America outcompetes the native lineage (haplotype P). Haplotype M situates at the fast-side of trait economic spectrum rather than haplotype P. The present study evaluated the plant traits and associated soil microbiome of the introduced and native Phragmites lineages using a common garden experiment in East China. Methods Four geographic groups including the introduced lineage of North America (NAint, haplotype M), native lineage of North America (NAnat, haplotype P), European group (EU, haplotype M) and Northwestern China group (CHN, haplotype M) were probed for plant traits and associated soil microbiome in two life-history stages – growing period and withering period. Results No significant differences in functional traits were shown among the four groups. The difference existed mainly in the soil microbial structure. The soils derived from the four groups had different bacterial generic structure however similar bacterial functional structure. NAint accumulated more orchid mycorrhizal fungi than the other three groups, while NAnat gathered more plant pathogenic and ectomycorrhizal fungi in the growing period. In the withering period, NAint accumulated more plant pathogenic fungi while NAnat gathered more arbuscular mycorrhizal fungai. NAint, EU and CHN shared different soil microbial structures despite the same haplotype. Conclusion The interaction between plant traits and soil microbiome seemed weak. However, the long-term effects of microbial transition on the introduced and native lineage are unknown and the potential plant-soil interactions need further exploration.
... Phragmites australis is a perennial grass that can reproduce clonally via rhizomes. It is ecologically adaptable and highly resilient (Packer et al., 2017). As a typical wetland plant, P. australis is a dominant and established species in inland salt marshes of the Western Songnen Plain, absorbing salt and purifying the water (Guan et al., 2017). ...
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Inland saline marshes in northeastern China have unique soil characteristics and population distribution features. Hydrological change is a critical environmental factor causing wetland degradation and soil salinization in this region. The growth and reproductive responses of typical wetland plants to dry-wet alternations are essential for restoring inland saline marshes. A pot experiment was conducted to study the growth and reproductive responses of Phragmites australis populations to three hydrological treatments simulating drought degradation (drought), permanent inundation restoration (flooding), and seasonal inundation restoration (dry-wet). The species showed different growth and reproductive responses to the three treatments. After 120 d, the drought conditions induced a lower biomass, root length and root surface area of P. australis , but with higher root diameter, soluble sugar, and Na ⁺ ion contents. Flooding and alternating dry-wet treatments induced the opposite responses. Alternating dry-wet treatments can be considered a better solution to effectively conserve water and meet the water needs of P. australis in the current growing season. The biomass under the alternating wet and dry treatment was the same as that under flooding, but the number of rhizome shoots was lower. The alternating dry-wet treatments was able to recover the growth of P. australis in the current season, but the potential for asexual reproduction of the species was insufficient.
... Shorelines are also habitats with limited spatial distributions, often characterised by high dominance and low diversity. For instance, common reed (Phragmites australis; Figure IB) forms monodominant stands along shorelines [79]. Common reed engineers wetland and shoreline ecosystems by changing sediment accumulation, decomposition, and nitrogen cycling [80,81], and forms dense mats that discourage competitors from becoming established [82]. ...
... Shorelines are also habitats with limited spatial distributions, often characterised by high dominance and low diversity. For instance, common reed (Phragmites australis; Figure IB) forms monodominant stands along shorelines [79]. Common reed engineers wetland and shoreline ecosystems by changing sediment accumulation, decomposition, and nitrogen cycling [80,81], and forms dense mats that discourage competitors from becoming established [82]. ...
Article
Plants and their environments engage in feedback loops that not only affect individuals, but also scale up to the ecosystem level. Community-level negative feedback facilitates local diversity, while the ability of plants to engineer ecosystem-wide conditions for their own benefit enhances local dominance. Here, we suggest that local and regional processes influencing diversity are inherently correlated: community-level negative feedback predominates among large species pools formed under historically common conditions; ecosystem-level positive feedback is most apparent in historically restricted habitats. Given enough time and space, evolutionary processes should lead to transitions between systems dominated by positive and negative feedbacks: species-poor systems should become richer due to diversification of dominants and adaptation of subordinates; however, new monodominants may emerge due to migration or new adaptations.
... In this study, we found that hydrology was the primary driver of community outcomes. Hydrology is known to have a strong influence on P. australis growth across life stages with deeply flooded conditions (> 5 cm above soil surface) limiting germination and emergence at early regenerative stages (Elhaak et al. 1993;Alvarez et al. 2005;Li et al. 2013) and flooded to moist soils promoting growth in adult plants (Packer et al. 2017). ...
Article
Sowing native seeds is a common approach to reintroduce native plants to degraded systems. However, this method is often overlooked in wetland restoration despite the immense global loss of diverse native wetland vegetation. Developing guiding principles for seed‐based wetland restoration is critical to maximize native plant recovery, particularly in previously invaded wetlands. Doing so requires a comprehensive understanding of how restoration manipulations, and their interactions, influence wetland plant community assembly. With a focus on the invader Phragmites australis, we established a series of mesocosm experiments to assess how native sowing density, invader propagule pressure, abiotic filters (water and nutrients), and native sowing timing (i.e., priority effects) interact to influence plant community cover and biomass in wetland habitats. Increasing the density of native seeds yielded higher native cover and biomass, but P. australis suppression with increasing sowing densities was minimal. Rather, community outcomes were largely driven by invader propagule pressure—Phragmites australis densities of ≤ 500 seeds/m2 maintained high native cover and biomass. Low‐water conditions increased the susceptibility of P. australis to dominance by native competitors. Early sowing of native seeds showed a large and significant benefit to native cover and biomass, regardless of native sowing density, suggesting that priority effects can be an effective restoration manipulation to enhance native plant establishment. Given the urgent wetland restoration need combined with the limited studies on seed‐based wetland restoration, these findings provide guidance on restoration manipulations that are grounded in ecological theory to improve seed‐based wetland restoration outcomes.
... Less correlated were road density (landscape structure) and land use (human activity). Packer et al. (2017) conducted a global assessment of the biology of common reed (Phragmites australis), which is particularly invasive in North and Central America, and projected declining populations in the British Isles and along the east coasts of the United States and Panama. The latter due to rising sea levels associated with climate change. ...
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Due to numerous human activities, organisms have been transported and either accidentally or deliberately introduced all around the globe. Biological invasions are now considered to be one of the main drivers of global change because many invasive plants have severe ecological, economic, and health consequences. Thus, there is an ever-growing need to better understand invasions to determine how specific plant species are able to establish in communities and, in many cases, expand their range. Here, we describe the invasion process and how it contributes to the invasion of plant communities. We present an invasion-factor framework (IFF) model that uses three factors (climate dynamics, ecosystem resistance, and invader fitness) to explain how each plays a role in the introduction of plants and their ultimate failure or success (i.e., becoming invasive). The invasion of plant communities starts with the uptake of propagules from the native range, followed by their transport to and release into a new territory, where they become established and can spread or expand. Propagule pressure, prior adaptation, anthropogenically induced adaptation to invade, and post-introduction evolution are several theories that have been posed to explain the establishment of invasive plants. Further, traits of invasive plants, either before (existing) or after (developed) introduction, provide a mechanistic understanding with direct ties to the three factors of the IFF. The IFF is a general guide with which to study the invasion process based on specific factors for individual invaders and their target communities. The IFF combines (a) climatic dynamics, analogous to environmental filters; (b) ecosystem resistance, which prevents invasive plants from becoming established even if they are able to overcome the climate factor; and (c) invader fitness, relating to the genetic diversity of invasive plants, which allows them to become established after overcoming climate and ecosystem resistance factors. Case studies from the literature provide examples of research investigating each of the three factors of the IFF, but none exist that describe all the factors at once for any given invasive plant species. The application of the IFF for management is most appropriate once an invasive plant has become established, as preventative measures before this point rely only on accurate identification (detection) and removal (response). The IFF model should be considered as a tool to establish research priorities and identify components in the invasion process and inform restoration efforts. We advocate that the IFF should be integrated into management practices to help in the decision-making process that contributes to more effective practices that reduce the occurrence and impacts of invasive plants in a range of communities.
... This plant can survive in both fresh and saltwater ecosystems, tolerating salinities up to 28 parts per thousand (ppt) (Bai et al., 2012). Due to its high intraspecies diversity, phenotypic plasticity and ability to build up biomass, P. australis is often the predominant species in the ecosystems it inhabits (Packer et al., 2017). ...
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Roseau cane (Phragmites australis (Cav). Trin. ex Steud.) is the dominant plant species of the Mississippi River Delta in Louisiana, USA, and protects the coastline from erosion and storm‐related impacts, maintaining shipping channels and oil infrastructure. Widespread dieback and thinning of P. australis were noted in the Mississippi River Delta in the fall of 2016. Invasive populations of the roseau cane scale (Nipponaclerda biwakoensis Kuwana), which is native to Asia, were found at outbreak levels in the stands. Subsequent research implicated N. biwakoensis in the diebacks. As a safe, cost‐effective and long‐term approach for managing this invasive scale, classical (importation) biological control methods are being considered. As the first step to developing biological control, research evaluating the natural enemies of the N. biwakoensis in the native range is necessary. This study investigated the population dynamics of N. biwakoensis and its associated parasitoids on P. australis in Taiwan from July to November 2019 at five study sites. Scale densities across sites increased over the growing season, peaking in September at 85.77 ± 6.36 scales/stem, which is half as dense as found in Louisiana. Mean parasitism of adult female scales across sites and season was 14.00%, while parasitism on immature scales was lower (3.00%). Four parasitoid wasp species were reared from the scale—Asytymachus lasallei Noyes and Higashiura, Boucekiella depressa Hoffer, Neastymachus japonicus Tachikawa and Aprostocetus sp. Westwood. Neastymachus japonicus was the dominant species parasitizing adult female scales, while A. lasallei was the dominant wasp species parasitizing immature scales. Astymachus lasallei and B. depressa were frequently reared from the same individual host, suggesting multiparasitism or hyperparasitism. Overall, this study provides important information on the identity and role of parasitoids of N. biwakoensis in its native range, which will aid in developing a classical biological control programme for the invasive N. biwakoensis.
... Additionally, invasive P. australis tolerates a wide range of environmental conditions. These include surviving in water depths ranging from 30 cm below to 70 cm above the ground-level (Haslam 1971), in salinities ranging from freshwater to salt marshes (e.g., Konisky and Burdick 2004;Vasquez et al. 2005), and in a wide range of soil nutrient concentrations (Packer et al. 2017)-for example, Meyerson et al. (1999) reported P. australis growing in soil with a range of 0.35-14.7 mg g -1 nitrogen. Invasive P. australis also responds positively to disturbance and nutrient addition by increasing the density and height of above-ground shoots (Minchinton and Bertness 2003) and generates more biomass when grown in elevated CO 2 treatments, suggesting it may fare better under climate change (Mozdzer and Megonigal 2012). ...
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Identifying the mechanisms that result in a “high impact” invasive species can be difficult. Coexistence theory suggests that detrimental invasive species can be better predicted by incorporating both niche differences and fitness differences than examining niche overlap alone. Specifically, detrimental invasive species should take up shared limited resources more efficiently than their neighbouring resident species. While there is clear evidence that invasive Phragmites australis is successfully displacing resident species, there remains few field studies that attempt to quantify the niche overlap and fitness difference between P. australis and the species it is displacing in the field. We measured differences in photosynthetic performance (carbon assimilation rate, δ¹³C, photosynthetic water use efficiency, biomass, light compensation point, light saturation point), canopy height and interception of photosynthetically active radiation, and niche overlap between P. australis and three resident freshwater wetland species (Calamagrostis canadensis, Carex aquatilis, and Typha spp.) growing with or without aboveground interspecific competition. Invasive P. australis intercepted more photosynthetically active radiation, had higher photosynthetic water use efficiency, a higher average light saturation point, and had a larger niche region compared to resident species. Resident plant species showed a significant decrease in photosynthetic performance when growing in competition with P. australis and had a high probability of overlap onto the niche space of P. australis. These results provide evidence that the ability of P. australis to reduce the availability of a required resource and more efficiently use it over the growing season, while exhibiting high niche overlap with resident species, likely contributes directly to its success in North American freshwater wetlands.
... m taller reeds than summers where cooler temperatures are observed [23], [24]. P. australis is highly productive in very high temperatures if sufficient amount of water is available to cool the leaves through transpiration [25]- [28]. ...
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Lake ecosystems are important elements of hydrological regime, the quality of these ecosystems is affected by anthropogenic actions, and therefore, a variety of organisms, living in these habitats depend on the applied management solutions. Due to human activities freshwater ecosystems suffer from loss of biodiversity and increased eutrophication. Therefore, important aspects related to lake management include knowledge about the water quality, ecosystem response to climate change as well as increased risks of appearance and spreading of invasive species. Water quality, content of oxygen, nutrients, phytoplankton and distribution of macrophytes, including invasive species were analysed in Balvu and Pērkonu lakes. Presence of invasive species Canadian waterweed ( Elodea canadensis ) was detected, however, common reed ( Phragmites australis ) can be considered as expansive species. The analysis of current situation and existing management measures indicates persistent spreading of those species. Significant changes of lake water quality and climate may increase possible spreading of other, more aggressive, invasive species, for example – Nuttall’s waterweed ( Elodea nuttallii ).
... P. australis enhances its ability to survive under flooding conditions by increasing the rate of evapotranspiration to enhance its protection and uptake of nutrients (Zhao et al., 2012;Srivastava et al., 2014). Furthermore, these macrophytes, through plant residue decomposition, nutrients uptake, and root exudates, modify the physiochemical parameters of the soil to enable their proliferation and possibly the remediation of the environment (Luigimaria et al., 2014;Hallin et al., 2015;Packer et al., 2017). Hence, the next subsection of this review looked at the physiological response of P. australis to environmental stress. ...
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Common reed ( Phragmites australis ) can invade and dominate in its natural habitat which is mainly wetlands. It can tolerate harsh environments as well as remediate polluted and environmental degraded sites such as mine dumps and other polluted wastelands. For this reason, this can be a very critical reed to reclaim wastelands for agricultural use to ensure sustainability. The present review manuscript examined the microbial spectra of P. australis as recorded in various recent studies, its physiological response when growing under stress as well as complementation between rhizosphere microbes and physiological responses which result in plant growth promotion in the process of phytoremediation. Microbes associated with P. australis include Proteobacteria, Bacteriodetes , and Firmicutes, Fusobacteria, Actinobacteria , and Planctomycete s families of bacteria among others. Some of these microbes and arbuscular mycorrhizal fungi have facilitated plant growth and phytoremediation by P. australis . This is worthwhile considering that there are vast areas of polluted and wasted land which require reclamation for agricultural use. Common reed with its associated rhizosphere microbes can be utilized in these land reclamation efforts. This present study suggests further work to identify microbes which when administered to P. australis can stimulate its growth in polluted environments and help in land reclamation efforts for agricultural use.
... These above results indicate that the presence of particular species in communities can increase N removal in floating CWs. P. australis and T. latifolia are widespread around the world and have been reported to enhance N removal (Vymazal 2011;Packer et al. 2017). Thus, plant species combinations that include P. australis or T. latifolia are recommended to treat wastewater with an increasing NH 4 + /NO 3 − ratio in floating CWs. ...
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Maintaining efficient and stable nitrogen (N) removal in constructed wetlands (CWs) that experience disturbance from their influent pollutant variations is crucial. The ammonium/nitrate (NH4+/NO3−) ratio of influent in CWs often varies widely. The N removal and stability in floating CWs have been found to be enhanced by manipulating plant species diversity. However, whether the positive effects occur in sand-based CWs remains unknown. Here, we established sand-based and hydroponic microcosms to investigate the differences in the responses of N removal and stability to plant species diversity under the disturbance of increasing influent NH4+/NO3− ratio in late period of plant growth. Results indicated that, (1) increasing plant species richness enhanced N removal but did not affect N removal stability in sand-based CWs under disturbance; (2) sand-based CWs had 46% higher average N removal stability than floating CWs, but the stability in floating CWs reached that in sand-based CWs at higher species richness levels; (3) under disturbed conditions, floating CWs with Phragmites australis or Typha latifolia achieved N removal and stability equivalent to those in sand-based CWs. This study indicates that, when treating wastewater with a variable NH4+/NO3− ratio, floating CWs with high plant species richness and specific species can achieve a win-win situation for high and stable N removal and bioenergy production.
... Additionally, invasive P. australis tolerates a wide range of environmental conditions. These include surviving in water depths ranging from 30 cm below to 70 cm above the ground-level (Haslam 1971), in salinities ranging from freshwater to salt marshes (e.g., Konisky and Burdick 2004;Vasquez et al. 2005), and in a wide range of soil nutrient concentrations (Packer et al. 2017) -for example, Meyerson et al. (1999) reported P. australis growing in soil with a range of 0.35-14.7 mg g − 1 nitrogen. Invasive P. australis also responds positively to disturbance and nutrient addition by increasing the density and height of above-ground shoots (Minchinton and Bertness 2003) and generates more biomass when grown in elevated CO 2 treatments, suggesting it may fare better under climate change (Mozdzer and Megonigal 2012). ...
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Identifying the mechanisms that result in a “high impact” invasive species can be difficult. Coexistence theory suggests that detrimental invasive species can be better predicted by incorporating both niche differences and fitness differences than examining niche overlap alone. Specifically, detrimental invasive species should take up shared limited resources more efficiently than their neighbouring resident species. While there is clear evidence that invasive Phragmites australis is successfully displacing resident species, there remains few field studies that attempt to quantify the niche overlap and fitness difference between P. australis and the species it is displacing in the field. Using P. australis we measured differences in photosynthetic performance (carbon assimilation rates, δ 13 C, photosynthetic water use efficiency, biomass), the effects of competition for photosynthetically active radiation, and niche overlap between P. australis and three resident freshwater wetland species ( Calamagrostis canadensis, Carex aquatilis, and Typha spp.) growing with or without interspecific competition . Invasive P. australis intercepted more photosynthetically active radiation, assimilated more carbon more efficiently, and had a larger niche region compared to resident species. Resident plant species showed a significant decrease in photosynthetic performance when growing in competition with P. australis and had a high probability of overlap onto the niche space of P. australis. These results provide evidence that the ability of P. australis to reduce the availability of a required resource and more efficiently use it over the growing season, while exhibiting high niche overlap with resident species, likely contributes directly to its success in North American freshwater wetlands.
... Reed plants are a shelter for bacteria, algae and zooplankton; they contribute to the diversification and balance of biological activity (ONA, 2014). They exploit the capacities of root systems to adapt to high pollution loads and to the conditions of anoxia or hypoxia of the substrate, leading to symbiotic relationships between microorganisms and roots that promote the elimination of pollutants (Kern and Idler, 1999), the fungal communities of healthy reed roots were the ten most diverse plant species (Packer, 2017). ...
... For common reed, nutrients come from the soil or the water (see Packer et al., 2017). The data of sediment nutrients (Table S1) were presented in our previous paper (Eid et al., 2020). ...
Article
This research was performed in order to compare the functional traits (morphology, density and biomass) of Phragmites australis (common reed): young vs. old populations which were analyzed along nutrient availability gradient in Lake Burullus (Egypt) every month for a year. The samples were gathered from six sites distributed equally along the northern and southern parts of this lake. The present study indicated that, water N, P, Ca and Mg concentrations of the southern sites were higher than those of the northern sites. Shoot height, stem diameter, number of leaves, flowering ratio, leaf area, and leaf area index (LAI) were significantly lower in young populations compared with old populations. However, shoot density was significantly higher in young populations compared with old populations. The above-ground biomass increased from February until it reached its maximum during August and then decreased again, while a decrease in below-ground biomass in spring to support the rapid shoot growth, followed by an increase in summer due to the shoot translocations in the reverse direction was indicated. The CR (common reed) exhibited a slower relative growth rate (RGR) during cooler months, September–December, while highest RGR was achieved during spring months, March–May. In Lake Burullus the results from this field work indicated that shoot height, stem diameter, number of leaves, flowering ratio, leaf area, LAI, and biomass of CR increased with increasing nutrients along north-south direction in Lake Burullus, where lake eutrophication influenced CR growth positively. Thus, the theory that the biomass and morphology of this macrophyte is determined by the water trophic content is reinforced. The collection of this data is valuable to further comprehend the growth cycle of CR and to contribute to the future management and utilization of CR in the Egyptian wetlands.
... The perennial grass can form over 3 m high, nearly monospecific stands with dense rhizome masses in the ground up to several decimetres thick. Common reed is widespread in shallow freshwater habitats like lake shores, swamps and carrs as well as in the saline conditions of saltmarshes and brackish lagoons (Packer et al., 2017). In contrast to its wide former distribution range (Streif, 1990), it is rather restricted along the diked coast today. ...
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Within the multidisciplinary WASA project, 160 cores up to 5 m long have been obtained from the back-barrier area and off the coast of the East Frisian island of Norderney. Thirty-seven contained basal peats on top of Pleistocene sands of the former Geest and 10 of them also had intercalated peats. Based on 100 acclerator mass spectrometry (AMS) ¹⁴ C dates and analyses of botanical as well as zoological remains from the peats, lagoonal sediments and the underlying sands, a variety of distinct habitats have been reconstructed. On the relatively steep slopes north of the present island, a swampy vegetation fringe several kilometres wide with carrs of alder ( Alnus glutinosa ) moved in front of the rising sea upwards of the Geest as it existed then until roughly 6 ka, when the sea level reached the current back-barrier region of Norderney at around −6 m NHN (German ordnance datum). From then on for nearly 4000 years a changing landscape with a mosaic of freshwater lakes and fens existed within this area. It was characterised by various stands of Cladium mariscus (fen sedge), alternating with brackish reed beds with Phragmites australis (common reed) and salt meadows with Aster tripolium (sea aster), Triglochin maritima (sea arrowgrass), Juncus gerardii (saltmarsh rush) as well as mudflats with Salicornia europaea (common glasswort). As far as shown by our cores, this highly diverse, and for humans potentially attractive landscape was at least some 4 km wide and followed the coast for about 10 km. Before the rising sea caused diversification of habitats, wet heath as well as dry and dusty sand areas existed. In the course of time, parts of the wet heath turned into raised Sphagnum bogs under an oceanic precipitation regime before this diverse landscape was drowned by the rising sea and finally covered by marine sediments, while the earlier sediments and peats were partly eroded and redeposited.
... Trin. ex Steud, halophyte, which is characterized by a wide geographical distribution amplitude (Clevering and Lissner 1999;Liang et al. 2013;Packer et al. 2017) and used as a resource for the field of energy or pharmaceutical industry, agricultural production and other human activities (Tewksbury et al. 2002;Qingquan et al. 2018). Recently, Shun-Cang Zhang et al. (2016) and Gordobl et al. (2019) revealed that vegetative organs (leaves, roots) and seeds of Phragmites australis as of other species are also used medicinally in the treatment of colds and bacterial-viral diseases, particularly in the treatment of diseases as bacterial meningitis, melanoma, arthritis, bronchitis, cancer, cholera, cough, diabetes, and many other diseases. ...
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The microstructure of leaf epidermis, the localization, and content of syringyl (S) and guajacyl (G) monolignol in epidermal cells of Phragmites australis grown in water and moderate drought soil on the bank of the Venetian strait of the Dnipro River in Kiev (Ukraine) were studied with the electron microscopic method and laser confocal microscopy. The trichomes, guard cells of stomata, epidermal cells of vaulted zones over veins of adaxial and abaxial surface contained syringyl and guajacyl, the content of which depended on plant ecotype. We established that moisture soil influenced the leaf epidermis ultrastructure, on the change of monolignols content and S/G ratio in epidermis leaf of reed. The investigations show that trichomes and the cells of the vaulted zone in the leaf epidermis were the main accumulator of monolignols. The obtained results suggest that change of the microstructure of leaves, content of the monolignols, and S/G ratio in leaves contribute to the preservation of optimal water status of plants and can be considered as the signs of plant phenotypic plasticity and adaptive marker depending on the conditions of water supply.
... Common reed (Phragmites australis (Cavanilles) Trinius ex Steudel) provides an excellent study system for uncovering the effects of hydrochory dispersal and habitat selection on genetic diversity. Common reed is a cosmopolitan wetland grass with diverse ecotypes distributed in riverine and non-riverine habitats (Clevering and Lissner, 1999;Packer et al., 2017). Common reed reproduces sexually by seeds and clonally by rhizomes, which are transported by floodwater over long distances McCormick et al., 2010). ...
Article
Understanding the driving mechanisms of local genetic diversity is a fundamental challenge under the global environmental changes. Rivers provide an excellent study system to demonstrate the effects of hydrochory dispersal and habitat selection on genetic diversity of riparian flora. In this study, we focused on the genetic variation of common reed (Phragmites australis) in the Yellow River Delta, China. Firstly, samples were collected in the Yellow River Delta, its neighboring wetland and its upstream plain. The genetic variation of P. australis was investigated using two chloroplast DNA fragments and eleven nuclear microsatellites. The findings showed that the genetic variation of P. australis in the Yellow River Delta belonged to two distinct lineages (haplotype O and haplotype P), which were similar to the upstream, and to the neighboring populations, respectively. Moreover, the genetic results suggested the potential dispersal of haplotype O from upstream to downstream. Secondly, we surveyed the plant functional traits of common reed from the Yellow River Delta in the field and in the common garden. The results showed significant differences between riverine and non-riverine populations in plant functional traits (e.g. specific leaf area and leaf length), haplotype composition and genetic clustering, which implied natural selection by habitat conditions. Lastly, we re-analyzed the plant performance data from a salt manipulation experiment with different haplotypes, and the results supported that salinity is a significant selective stressor on P. australis lineages in the Yellow River Delta. Our study highlights the significance of hydrochory dispersal and habitat selection in the river effects on genetic diversity of riparian flora, and provides important information for biodiversity conservation and wetland management in the Yellow River Delta.
... It was found that P. australis reached the greatest density and coverage at 30 cm water depth and tolerated fluctuations up to 25 cm in estuary wetlands, such as the Yellow River Delta (Cui et al., 2010). It was also reported that P. australis is intolerant to strong water movements (Packer et al., 2017). Phenotypic plasticity of morphology and biomass allocation in P. australis play important roles in responding to increased or fluctuating water depth (Vretare et al., 2001). ...
Article
Greater differences in hydrologic conditions are expected between coastal and inland wetlands with global climate change. Local adaptation has been considered as a significant driver of intraspecific differentiation in heterogeneous habitats. The common reed Phragmites australis is a cosmopolitan wetland species with high genetic variability and adaptability. In our study, reeds collected from coastal and inland wetlands were subjected to three stable water level gradients and two fluctuation frequencies in a common garden experiment. We measured their aboveground and belowground biomass, height, density, stem diameter, leaf water potential, specific leaf area, and photosynthetic parameters. Our results showed that P. australis exhibited high tolerance to stable and fluctuating water levels up to 30 cm depth. Increased shoot elongation rate and water-use efficiency promoted the establishment of P. australis in flooding habitats. The common reeds in the high-frequency water level fluctuation had a shorter shoot height and a lower shoot density than those in the low-frequency one. The coastal populations performed better under high (30 cm) and low (0 cm) water levels than the inland populations , which preferred shallow water (15 cm). The adaptation strategies of coastal and inland reeds to fluctuation frequencies were no different. We concluded that local adaptation might occur in P. australis populations due to different water levels rather than fluctuation frequency in coastal and inland wetlands. Our findings could provide a theoretical basis on the effects of flooding on intraspecific variation of wetland plants in future environmental change scene.
... It also inhabits aquatic ecosystems of high salinity, high metal content, low fertility and wide pH range, even then attaining high biomass productivity (Bonanno and Giudice 2010;Bonanno 2013;Prica et al. 2019;Quan et al. 2007;Srivastava et al. 2014). Its wide global distribution and true cosmopolitan nature arise from its specific ecophysiological strategies, broad ecological amplitudes based on high phenotypic plasticity and high evolutionary potential (Eller et al. 2017;Kettenring et al. 2015Kettenring et al. , 2016Packer et al. 2017). Its ability to remove toxic metals from the water and sediment, and accumulate them in its large underground and aboveground biomass, makes the common reed suitable for ecorestoration of polluted aquatic ecosystems (Bacchetta et al. 2015;Cicero-Fernández et al. 2017;Eller et al. 2017;Esmaeilzadeh et al. 2016;Prica et al. 2019;Stolz and Greger 2002). ...
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AimsPhragmites australis grows as a pioneer plant species in several mine and flotation tailings ponds distinguished by extremely high concentrations of metals. The main goals of this study were to estimate the effects of the specific concentrations and combinations of accumulated metals on the efficiency of antioxidative enzymes and plant oxidative status. This study is relevant to our understanding of the common reed exceptional capacity to endure extreme edaphic conditions.Methods Metal concentrations were determined in the sediment, roots and leaves. Antioxidative enzymes activities, amounts of pigments and phenolics, total antioxidative capacity (TAC), lipid peroxidation level (LP) were analysed in plant organs.ResultsEffects of accumulated metals depended on their concentrations and their stoichiometry. Antioxidative enzymes and TAC in roots were significantly reduced, resulting in consequent increase in LP. Pb concentration in leaves did not significantly change enzymes activities, whereas toxic level of Cu impeded activity of catalaze and ascorbate peroxidase.Conclusions The results indicate that in the conditions of high root metal contamination the mechanisms involved in their immobilization and detoxification cannot completely restrain their toxicity. Their effects on enzymes activities depend on the type of enzyme, metal concentrations, specific ratios and interactions.
Article
Recent results revealed that considerable Pb accumulation in plants is possible under specific soil conditions that make Pb phytoavailable. In this review, the sources and transformations of Pb in soils, the interaction of Pb with bacteria and specifically the microbiota in the soil, factors and mechanisms of Pb uptake, translocation and accumulation in plants and Pb toxicity in living organisms are comprehensively elaborated. Specific adsorption and post-adsorption transformations of Pb in soil are the main mechanisms affecting the mobility, bioavailability, and toxicity of Pb. The adsorption ability of Pb largely depends on the composition and properties of soils and environmental conditions. Microbial impact on Pb mobility in soil and bioavailability as well as bacterial resistance to Pb are considered. Specific mechanisms conferring Pb-resistance, including Pb-efflux, siderophores, and EPS, have been identified. Pathways of Pb entry into plants as well as mechanisms of in planta Pb transport are poorly understood. Available evidence suggests the involvement of Ca transporters, organic acids and the phytochelatin pathway in Pb transport, mobility and detoxification, respectively.
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Aims Widespread species of Phragmites australis, has a high degree of intraspecific variation in functional traits during external climatic and environmental changes. However, the underlying mechanism of the environmental gradient changes at regional scale on intraspecific variation and adaptation strategies of species functional traits are still not well understood. Methods Morphological traits, nutrient contents, and stoichiometric ratios of P. australis in lakeshore wetlands of semi-arid and arid regions in the Inner Mongolia Plateau were investigated to reveal the variability of functional traits at different regional scales and the influencing factors and to reveal the ecological adaptation strategies of P. australis in different regions through plant economic spectrum. Results The functional traits of P. australis varied significantly within the species at different scales, and the variation has a significant latitude pattern. Climatic factors determine the intraspecific variation of the functional traits of P. australis, and the influence of soil properties is small. Plant economic spectrum theory is also applicable to the functional traits of various organs and whole plants of P. australis, and different ecological adaptation strategies are confirmed across arid and semi-arid regions. Conclusions Intraspecific variation of functional traits of P. australis originates from temperature-mediated climatic differences brought about by sampling geographic locations, rather than the soil properties of the sampling locations. The utilization and assimilation of resources of P. australis are conservative in arid regions, while in semi-arid regions it is an acquisition strategy.
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There are different environmental pressures in coastal and inland wetlands resulting in phenotypic variation among plant populations, which might be related to epigenetic modifications. Phragmites australis is a widespread plant in coastal and inland wetlands, and the phenotype of the population is selected by salinity, but the reasons for the population differences in salt tolerance and phenotype are unclear. We investigated coastal and inland P. australis populations grown under two salinities and two manipulated DNA methylation levels in common gardens. The plants were sprayed with 5-azacytidine (DNA demethylation agent) regularly, and the physiological and morphological traits of reeds were measured. Plant height, density, and basal stem of reeds from different sources were significantly different and correlated with soil conductivity of sampling sites (P < 0.05). Salinity significantly decreased the biomass (37.04%, P < 0.05) and plant height (24.68%, P < 0.05) of inland reeds but had no significant effect on coastal populations (13.48%). P. australis responds to salt stress through phenotypic plasticity, and inland wetland populations exhibit local adaptation to freshwater. Increased salt tolerance in inland populations following DNA demethylation, particularly biomass, plant height, and basal stems (increased 23.62%; 13.08%; 5.35%, respectively), could provide more opportunities in adverse environments. This study will provide important insights into the highly adaptive mechanisms of the large non-model plant.
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The dynamics of composition and properties of dissolved organic matter in soil depend on plant carbon inputs and microbial degradation. However, uncertainties remain regarding the relative contributions of different plant carbon inputs sources, i.e., from litter decomposition versus rhizodeposits, to soil dissolved organic matter, which may limit the understanding of soil carbon dynamics. In this study, effects of plant carbon inputs from either rhizodeposition or litter (leaf, stem, rhizome, and root litter) decomposition on composition and optical properties of soil dissolved organic matter were estimated. Rhizodeposition and litter decomposition of P. australis had significant effects on soil dissolved organic matter, and its variation was mainly associated with the third fluorescent component (C3). Effects of rhizodeposition on soil dissolved organic matter were significantly altered by soil salinity, exhibiting increased chromophoric dissolved organic matter and fulvic acid C3 under saline conditions. Effects of litter decomposition on soil chemistry and dissolved organic matter varied greatly among plant tissues. Compared with rhizome and root, leaf and stem decomposed more thoroughly and significantly increased the contents of fulvic acid C3. This was supported by increased aromaticity associated with leaf inputs and increased plant-derived dissolved organic matter associated with stem and leaf inputs. These findings highlight the significant influence of rhizodeposition and litter decomposition on soil dissolved organic matter, and suggest that the roles of salinization and plant tissue type merit consideration in further studies on plant–soil carbon cycling.
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Plant invasions often lead to homogenization of plant communities, but the potential for homogenization of other trophic levels is understudied in many systems. Biotic communities in coastal wetlands are closely tied to daily and yearly water-level fluctuations. We compared the bird community in invasive Phragmites australis (European common reed) habitat and remnant, uninvaded marsh in a year with average water depths and a year with above-average water depths in Long Point (Ontario, Canada), a World Biosphere Reserve. Our results demonstrate the spatial and temporal homogenization of the wetland bird community following P. australis invasion. The bird community present in P. australis was a nested subset of the species present in remnant marsh, and total beta diversity in P. australis habitat decreased when water depths were above average. In contrast, total beta diversity was high in remnant marsh vegetation. The distinctively structured vegetation zones in remnant marsh yield structural complexity and habitat heterogeneity that support greater taxonomic turnover in the bird community. These results provide evidence that invasion by a plant has resulted in the biological homogenization of the wetland bird community and illustrate that habitat use will change with prevailing environmental conditions, such as high- and low-water levels.
Chapter
Due to numerous human activities, organisms have been transported and either accidentally or deliberately introduced all around the globe. Biological invasions are now considered to be one of the main drivers of global change because many invasive plants have severe ecological, economic, and health consequences. Thus, there is an ever-growing need to better understand invasions to determine how specific plant species are able to establish in communities and, in many cases, expand their range. Here, we describe the invasion process and how it contributes to the invasion of plant communities. We present an invasion-factor framework (IFF) model that uses three factors (climate dynamics, ecosystem resistance, and invader fitness) to explain how each plays a role in the introduction of plants and their ultimate failure or success (i.e., becoming invasive). The invasion of plant communities starts with the uptake of propagules from the native range, followed by their transport to and release into a new territory, where they become established and can spread or expand. Propagule pressure, prior adaptation, anthropogenically induced adaptation to invade, and post-introduction evolution are several theories that have been posed to explain the establishment of invasive plants. Further, traits of invasive plants, either before (existing) or after (developed) introduction, provide a mechanistic understanding with direct ties to the three factors of the IFF. The IFF is a general guide with which to study the invasion process based on specific factors for individual invaders and their target communities. The IFF combines (a) climatic dynamics, analogous to environmental filters; (b) ecosystem resistance, which prevents invasive plants from becoming established even if they are able to overcome the climate factor; and (c) invader fitness, relating to the genetic diversity of invasive plants, which allows them to become established after overcoming climate and ecosystem resistance factors. Case studies from the literature provide examples of research investigating each of the three factors of the IFF, but none exist that describe all the factors at once for any given invasive plant species. The application of the IFF for management is most appropriate once an invasive plant has become established, as preventative measures before this point rely only on accurate identification (detection) and removal (response). The IFF model should be considered as a tool to establish research priorities and identify components in the invasion process and inform restoration efforts. We advocate that the IFF should be integrated into management practices to help in the decision-making process that contributes to more effective practices that reduce the occurrence and impacts of invasive plants in a range of communities.KeywordsClimate factorEcosystem resistance factorInvader fitness factorMultistep invasion processPhenotypic trait diversityPropagule pressureSpatial scales
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Manipulating plant microbiomes may provide control of invasive species. Invasive Phragmites australis has spread rapidly in North American wetlands, causing significant declines in native biodiversity. To test microbiome effects on host growth, we inoculated four common fungal endophytes into replicated Phragmites genotypes and monitored their growth in field and growth chamber environments. Inoculations were highly successful in the growth chamber but inoculated plants in the field were rapidly colonized by diverse endophytes from the local environment. There were significant genotype effects and minimal inoculation effects in both experiments with a significant inoculation × genotype interaction on tiller height in the field. Our results demonstrate that endophyte inoculation treatments are feasible, but repeated inoculations may be required to maintain high titer in plants subject to endophyte colonization from the local environment. Future studies should investigate a wider range of fungal endophytes to identify taxa that inhibit Phragmites and other invaders.
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Nature-based solutions, principally diverse systems, are increasingly being promoted as the solution to future food production as they are perceived to be more productive, resilient and ecologically based. This ‘paradigm of in-field diversity’ approach is inciting a growing perception that monocultures, the source of most global food production, are ecologically dysfunctional and highly vulnerable to diseases and pests. Our perspective paper clearly shows that natural monodominant vegetation is common in nature and that the ancestral species of major cereals including wheat, barley and rice grew in monocultures maintained by disturbances such as fire or flood. Early farmers mimicked these ecological stresses during field management, favouring annual monodominant crops. We also present well-supported evidence that cereal monocultures are an ancient method of farming founded in the origins of agriculture and that modern plant breeding generates and supports monoculture crops that are inherently genetically diverse and usually resistant to prevailing diseases and pests. Until research has been done on the ecology, agronomy and management of diverse nature-based solutions to future agriculture, the scarce funding to agricultural research for future food production is better targeted at improving monoculture agriculture to be more efficient, productive, resilient and environmentally benign. Monoculture agriculture, particularly for cereals, is a proven natural model for future food production.
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Over the past centuries, wet areas have faced major threats and surface reductions due to urbanization, pollution and hydrotechnical arrangements. Concrete dams took the place of riparian forests and marshes especially in the urban, peri-urban and even rural areas as a flood control method. Even though in the past two or more decades in the Western part of the E.U. and U.S.A. the general trend was to restore riverbeds from concrete to their natural state, in Romania the trend has followed the opposite direction with repercussions on biodiversity, water quality and difficult invasive species control. In the summer of 2021 we have botanically surveyed the Bega river in the eastern part of Timișoara in order to investigate the benefits that this naturalized state brings to the city and European biodiversity conservation efforts. Our survey led to the identification of key species for conservation and favorable habitat conservation status, resulted from habitat mapping of the area. We identified seven main habitat types: 92A0, 3150 (Natura2000); G5.1, X25 (EUNIS) and R5307, R5309, R5310 (Romanian system). Our study aims to bring attention to such sites and their importance as biodiversity holders in urban landscapes and as ecosystem service provides and to further reconsideration of the methods used in their future development.
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The study was to investigate the characteristics of Phragmites australis (Gramineae) silicon (Si) accumulation, and the response relationship between P. australis Si accumulation and groundwater depth changes. Plants were dig out and taken back to the laboratory for Si accumulation analysis, and a supplementary survey of P. australis Si accumulation was conducted among different groundwater depths. Result showed that Si absorbed and accumulated by P. australis mainly came from the soil and the Si accumulation differed significantly in tissues and growth stages, and the total Si accumulations (withering stage) of P. australis in sand dune (SD), desert steppe (DT), interdune lowland (IL), saline meadow (SM) and wetland (W) habitats were 7.09 %, 6.77 %, 5.72 %, 7.73 %, and 8.12 %, respectively. More importantly, P. australis Si accumulation was almost equal to the total accumulation of nitrogen, phosphorus and potassium, and even higher than of the total accumulation of calcium, magnesium and sulphur. P. australis Si accumulation (withering stage) reduced first from SD to DT habitat, and then increased remarkably from DT to W habitat with a significant increase of -23.95 % and 41.96 %, respectively. P. australis Si accumulation positively responds to the groundwater depths, and the relationship was an increasing linear function of one variable. Findings suggested that accumulating Si might be one of the effective strategies for P. australis to adapt to adverse habitats, and the Si rich characteristic of P. australis was likely to lay a solid theoretical foundation for exploring effective measures to restore and reconstruct the degraded ecosystems in desert oasis areas.
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The soil environment is a key factor affecting the distribution of plant communities. The soil environments of many arid wetland areas are deteriorating. The present study investigated plant-soil relationships in an arid wetland region (along the middle reaches of Heihe River, Northwest China). The main objective was to establish an approach to use plants as bioindicators of soil conditions. With such an approach, environmental changes inferred from plant observations can be monitored, facilitating the prevention of negative environmental impacts and the improvement of environmental management. Collection of vegetation data and soil sampling was conducted at a total of 87 plots from 27 stations in the study area from July to August 2017. The vegetation data included plant community type and the abundance, height, and coverage of each species. The soil characteristics included salinity (SA), pH, water content (WC), bulk density (BD), soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). A total of 13 main plant community types were identified by detrended correspondence analysis. The soil physicochemical properties varied among the different plant communities. Multivariate analysis showed that the vegetation variables were closely related to SA, pH and WC. The quantitative plant-soil relationships was also established to aid the management of the wetlands. Based on the established relationships, an expansion of Calamagrostis spp. would suggest a decrease in soil SA, a replacement of Inula japonica with Equisetum ramosissimum would indicate an increase in soil pH, and an expansion of Tamarix spp. would suggest increases in soil SA and pH. Our results support the use of plants as soil bioindicators of disturbance and the approach of quantitative plant-soil relationship to improve the environmental management of wetland ecosystems in arid areas.
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Wetlands play an important role in reducing the impact of nitrogen pollution on natural aquatic environments. However, during the plant wilting period (winter) there will inevitably be a reduction in nitrogen removal from wetlands. Understanding optimum harvest time will allow the use of management practices to balance the trade-off between nitrogen removal and the sustainability of wetlands. In this study, we investigated wetland nitrogen removal and reed (Phragmites australis) nutrient responses for two years [first year: influent total nitrogen (TN) 17.6–34.7 mg L⁻¹; second year: influent TN 3.2–10.0 mg L⁻¹] to identify the optimal harvest time: before wilting, mid-wilting, or late wilting. Harvesting decreased wetland nitrogen removal in both years, with later harvest time producing a smaller decrease in TN and ammonium-nitrogen (NH4⁺–N) removal. In addition to harvest before wilting, aboveground reed harvest at mid-wilting harvested more nutrients [carbon (C) 7.9%, nitrogen (N) 46.6% and phosphorus (P) 43.6%] in the first year, while harvest at late wilting harvested more nutrients (C 4.9%, N 7.8% and P 24.1%) in the second year, although this was not statistically significant. The late wilting harvest caused fewer disturbances to root stoichiometric homeostasis in the first year, while mid-wilting harvest promoted root nutrient availability in the second year. In addition, redundancy analysis (RDA) showed that root stoichiometry was interrelated with wetland nitrogen removal. Our results suggest that optimal harvest time was late wilting on the basis of wetland nitrogen removal, or either mid- or late wilting according to reed nutrient response to influent nitrogen concentration in some years. Our results provide crucial information for winter wetlands management.
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Using a cytochemical method and laser confocal microscopy, a sensitivity of content and distribution of monolignols in the leaves of Phragmites australis, grown in different natural conditions, was established. The leaves at stage of vegetative growth of two ecotypes of Ph. australis, which grew in water and on land, were studied. We present results obtained by comparing the data on the leaves of Ph. australis of air-water and terrestrial plants growing in natural conditions (Kyiv, Ukraine). It was found that the decrease in soil moisture leads to an increase in ratio of syringyl monolignol to guaiacyl (S-G) and to an increase in total content of monolignols (S+G) in epidermis and tissues of vessel bundles of the terrestrial plants. It was assumed that changing the ratio of monolignols and changing their content in the epidermis of leaves of terrestrial reed plants is one of the mechanisms of plant adaptation to lower soil moisture, which reduces transpiration and maintains optimal water potential in leaves of Ph. australis growing on land. Based on the obtained experimental data, we believe that high content of syringyl monolignol, which gives high strength to leaves and stems of terrestrial reeds, can serve as a marker for commercial use of these plants in various sectors of economy.
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Phragmites australis (common reed) is a cosmopolitan and competitive wetland grass that can tolerate a broad range of environmental conditions. Its tendency to become invasive in wetlands by rapidly forming dense monodominant stands that out-compete other species has made it a focus of research internationally. Disturbances can facilitate expansion of dominant P. australis stands, which can alter vegetation communities through mechanisms such as high evapotranspiration and litter accumulation. This expansion and dominance is occurring in the critically endangered swamps of the Fleurieu Peninsula in southern Australia, which have been anthropogenically fragmented, degraded, and modified. These swamps are of particular importance to rare species such as the endangered Mount Lofty Ranges southern emu-wren. The project was instigated and funded by the Conservation Council of South Australia and the Department of Environment, Water and Natural Resources due to concern that the dense stands of P. australis within the study system (Black Swamp) are impacting on habitat quality for the emu-wren and other threatened biota. Two contiguous areas within the study system, visually representing Phragmites-dominated and mixed communities, with different disturbance histories (grazed 20 and 14 years ago consecutively) were compared to investigate the influence of disturbance intensity (grazing) and monodominant Phragmites on the vegetation communities. The overarching aim of the study was to understand the influence of Phragmites within the Black Swamp and Tookayerta System and to determine the reasons for its expansion in the region. Field, greenhouse and spatial methods were combined to identify the drivers and mechanisms if P. australis dominance and expansion. The two communities were found to be functioning as alternate states of P. australis reedland; which was driving the transition to alternate states by creating a feedback loop, facilitating the succession of the systems. Evidence of these alternate states was given by biotic and abiotic conditions, whose interactions were found to be influencing species composition and density based on the disturbance history timelines of the two communities. Significant differences were found between the two communities in abiotic (including water depth, soil pH, salinity and nutrient conditions) and biotic variables (including vegetation composition, functional groups, litter depth and P. australis productivity). Litter depth and water table had the strongest influence on the alternate states of the two vegetation communities. A conceptual model is proposed to explain the feedback mechanisms between litter and water table that appear to be driving transitions between stable states of P. australis in the study system. One of the potential methods for controlling P. australis in the Fleurieu Peninsula Swamps (cutting and flooding of stems) was also tested with a greenhouse and pond experiment to further investigate these mechanisms of P. australis competitiveness and to optimise the technique for on-ground management. Cutting and flooding the stems was found to reduce P. australis productivity. Expansion of P. australis was apparent in aerial imagery, which was used to support the findings of the study, and further evidence of the alternate states of the wetland system. The findings of this research have already been integrated into conservation management of the critically endangered Fleurieu Peninsula Swamps and follow-up trials of P. australis control will be undertaken by the Conservation Council of South Australia. As managing P. australis is a challenge across its cosmopolitan range, both to control where it is invasive (introduced) and conserve where it is threatened (native), the findings and state-and-transition model proposed here will help inform optimal management strategies.
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Invasion biology research, often performed by scientists at relatively small spatial scales, provides experimental precision but may be limited in generalizability. Conversely, large-scale invasive species management represents a largely untapped wealth of information on invasion ecology and management, but such data are difficult to capture and synthesize. We developed a network (“PhragNet”) of individuals managing wetlands occupied by native and non-native lineages of the invasive wetland grass Phragmites australis (common reed). This network collected environmental and genetic samples, habitat data, and management information to identify environmental and plant community associations of Phragmites invasion and patterns of management responses. Fifty managers overseeing 209 Phragmites stands in 16 US states and ON, Canada participated. Participants represented federal agencies (26%), municipalities (20%), NGOs (20%), academia (14%), state agencies (12%), and private landowners (8%). Relative to the native lineage, non-native Phragmites occurred in areas with higher nitrate/nitrite and ammonium than non-native Phragmites. Stand interiors had higher soil electrical conductivity than nearby uninvaded areas, consistent with use of road salt promoting spread of Phragmites. Non-native Phragmites co-occurred with fewer plant species than native Phragmites and was actively targeted for management. Herbicide was applied to 51% of non-native stands; surprisingly, 11% of native stands were also treated with herbicide. This project demonstrates the utility of crowdsourcing standardized data from resource managers. We conclude by describing how this approach could be expanded into an adaptive management framework, strengthening connections between wetland management and research.
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Much has been done to address the challenges of biological invasions, but fundamental questions (e.g., which species invade? Which habitats are invaded? How can invasions be effectively managed?) still need to be answered before the spread and impact of alien taxa can be effectively managed. Questions on the role of biogeography (e.g., how does biogeography influence ecosystem susceptibility, resistance and resilience against invasion?) have the greatest potential to address this goal by increasing our capacity to understand and accurately predict invasions at local, continental and global scales. This paper proposes a framework for the development of ‘Global Networks for Invasion Science’ to help generate approaches to address these critical and fundamentally biogeographic questions. We define global networks on the basis of their focus on research questions at the global scale, collection of primary data, use of standardized protocols and metrics, and commitment to long-term global data. Global n
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The juxtaposition of plant-species invasions with latitudinal gradients in herbivore pressure is an important yet mostly unexplored issue in invasion biology. Latitudinal clines in defense and palatability to herbivores are expected to exist in native plant species but the evolution of these clines may lag behind for invasive plant species resulting in non-parallel latitudinal clines that may impact invasion success. Our study focused on a native and European invasive lineages of the common reed Phragmites australis in North America. Using native and invasive genotypes of P. australis collected across a 17° latitudinal range, we performed experiments in replicate northern and southern common gardens to investigate whether these two lineages exhibited different genetically based latitudinal clines in defenses, nutritional condition and palatability to their herbivores, the aphid Hyalopterus pruni and the fall armyworm Spodoptera frugiperda. We also tested whether invasive genotypes are more phenotypically plastic than native genotypes and whether plasticity varies with latitude. Although invasive genotypes did not exhibit higher defense levels (leaf toughness, phenolics, % carbon), they were considerably less palatable to their herbivores than native genotypes. Genetic-based latitudinal clines were evident for both native and invasive P. australis and for all defenses, nutrients and at least one palatability trait for each herbivore. In 36% of the cases where clines were evident, they were non-parallel between the two lineages. These data suggest that clines in the invasive genotypes of P. australis evolved within the past ~100 years. Moreover, our study showed that the occurrence and direction of latitudinal clines in plant traits were commonly dependent on where the study was conducted (north or south), indicating strong phenotypic plasticity in these genetic-based clines. Finally, traits for invasive genotypes of P. australis were 2.5 times more plastic than traits for native genotypes. Interestingly, plasticity for native but not invasive genotypes was strongly dependent on latitude of origin. Such spatial heterogeneity within and between the native and invasive lineages of P. australis with respect to their interactions with herbivores can generate substantial spatial variability in biotic resistance that can have important implications for the establishment and spread of invasive genotypes and species.
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The genus Phragmites includes several species, of which only Phragmites australis has a worldwide distribution. It has been several decades since the last formal taxonomic examination of the genus and a number of recent genetic studies have revealed novel diversity and unique lineages within the genus. In my initial work on genetic variation in Phragmites (Saltonstall in Proc Nat Acad Sci 99:2445–2449, 2002), I came up with a naming scheme for identifying chloroplast DNA haplotypes which combined unique sequences at two loci, designated by numbers, to form haplotypes, designated by letters. Here I describe this naming system in more detail, explain how it has evolved over time as more genetic data has become available, provide a summary of all haplotypes currently available on GenBank, and address some common misunderstandings about how the haplotypes are named.
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We studied the relationship between genome size and ploidy level variation and plant traits for the reed grass Phragmites australis. Using a common garden approach on a global collection of populations in Aarhus, Denmark, we investigated the influence of monoploid genome size and ploidy level on the expression of P. australis growth, nutrition and herbivore-defense traits and whether monoploid genome size and ploidy level play different roles in plant trait expression. We found that both monoploid genome size and latitude of origin contributed to variation in traits that we studied for P. australis, with latitude of origin being generally a better predictor of trait values and that ploidy level and its interaction with monoploid genome size and latitude of origin also contributed to trait variation. We also found that for four traits, tetraploids and octoploids had different relationships with the monoploid genome size. While for tetraploids stem height and leaf water content showed a positive relationship with monoploid genome size, octoploids had a negative relationship with monoploid genome size for stem height and no relationship for leaf water content. As genome size within octoploids increased, the number of aphids colonizing leaves decreased, whereas for tetraploids there was a quadratic, though non-significant, relationship. Generally we found that tetraploids were taller, chemically better defended, had a greater number of stems, higher leaf water content, and supported more aphids than octoploids. Our results suggest trade-offs among plant traits mediated by genome size and ploidy with respect to fitness and defense. We also found that the latitude of plant origin is a significant determinant of trait expression suggesting local adaptation. Global climate change may favor some genome size and ploidy variants that can tolerate stressful environments due to greater phenotypic plasticity and to fitness traits that vary with cytotype which may lead to changes in population genome sizes and/or ploidy structure, particularly at species’ range limits.
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Chloroplasts contain several copies of their DNA, and intra-individual haplotypic variation (heteroplasmy) is common in plants, but unexplored in the cosmopolitan genus Phragmites. The aims of this study were to assess if heteroplasmy due to paternal leakage of the chloroplast occurs in Phragmites and which new insights into the evolutionary history of Phragmites australis in North America can be identified from the heteroplasmic variation. Eight non-native P. australis haplotypes occur in North America and can interbreed with P. australis ssp. americanus and P. australis var. berlandieri, creating opportunities for biparental inheritance of distinctive haplotypes. The polymorphism in the trnT-trnL sequence length revealed seventeen cases of heteroplasmy worldwide, in contact zones of distantly related haplotypes and in known hybrid populations, nine of which occurred in North America. In America, the cloned sequences, combined with nuclear markers, identified recombined haplotypes between native P. australis ssp. americanus and invasive P. australis haplotype M, and between the species P. mauritianus and P. australis, due to chloroplast paternal leakage. The occurrence of heteroplasmy and recombined haplotypes suggest a local origin for some of the rare non-native haplotypes occurring in North America, and plastid leakage events in the evolutionary histories of P. australis ssp. americanus and P. australis var. berlandieri.
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Wetland plants actively provide oxygen for aerobic processes in submerged tissues and the rhizosphere. The novel concomitant assessment of diurnal dynamics of oxygen and carbon dioxide concentrations under field conditions tests the whole-system interactions in plant-internal gas exchange and regulation. Oxygen concentrations ([O2]) were monitored in-situ in central culm and rhizome pith cavities of common reed (Phragmites australis) using optical oxygen sensors. The corresponding carbon dioxide concentrations ([CO2]) were assessed via gas samples from the culms. Highly dynamic diurnal courses of [O2] were recorded, which started at 6.5-13% in the morning, increased rapidly up to 22% during midday and declined exponentially during the night. Internal [CO2] were high in the morning (1.55-17.5%) and decreased (0.04-0.94%) during the rapid increase of [O2] in the culms. The observed negative correlations between [O2] and [CO2] particularly describe the below ground relationship between plant-mediated oxygen supply and oxygen use by respiration and biogeochemical processes in the rhizosphere. Furthermore, the nocturnal declining slopes of [O2] in culms and rhizomes indicated a down-regulation of the demand for oxygen in the complete below ground plant-associated system. These findings emphasize the need for measurements of
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The cosmopolitan reed grass Phragmites australis (Poaceae) is an intensively studied species globally with a substantial focus in the last two decades on its invasive populations. Here we argue that P. australis meets the criteria to serve as a model organism for studying plant invasions. First, as a dominant species in globally important wetland habitats, it has generated significant pre-existing research, demonstrating a high potential for funding. Second, this plant is easy to grow and use in experiments. Third, it grows abundantly in a wide range of ecological systems and plant communities, allowing a broad range of research questions to be addressed. We formalize the designation of P. australis as a model organism for plant invasions in order to encourage and standardize collaborative research on multiple spatial scales that will help to integrate studies on the ecology and evolution of P. australis invasive populations, their response to global environmental change, and implications for biological security. Such an integrative framework can serve as guidance for studying invasive plant species at the population level and global spatial scale.
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In South Africa, wetland plants have been used for centuries and they continue to be harvested for subsistence and commercial purposes. Fibres for crafts are collected by cutting the aboveground parts. KwaZulu-Natal is one or the major basket-producing regions in southern Africa and at least twenty-two species of wetland plants are harvested for crafts. A literature review of the harvested species revealed that the impacts of cutting have only been extensively investigated for Phragmites australis (Cav.) Steud. and Juncus kraussii Hochst. The review suggested that, where plants display strong seasonal aboveground productivity patterns, cutting should take place after shoot senescence and before new shoot emergence to minimize damage to plants. Cutting in the short term could increase the density of green stems. However, in the long term in Phragmites australis. it may deplete the rhizome reserves and reduce the density of useable (longer and thicker) culms. The opportunity for sustainable harvests was investigated by considering the geographic distribution, whether species are habitat specific or not, and local population sizes of the craft plants. Juncus kraussii is of the greatest conservation concern. Ecologically sustainable wetland plant harvesting could contribute to the wise use of wetlands, an approach promoted nationally and internationally.
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Increasing salinity and alkalinity in soil and water has drawn much attention over the past two decades. Salinity or alkalinity significantly influences plant growth. When salinity and alkalinity were combined, the effect on photosynthesis of plant was much complex, however, the underlying basis in photosynthetic capacity under combined salinity-alkalinity stress is yet not fully understood. In northeastern China, many Phragmites-dominated wetlands have been markedly salinized and alkalinized due to overexploitation or water resources shortage and climate change. The mechanism of degradation of Phragmites-dominated wetlands has become an important aspect of ecological protection studies within the last two decades. Photosynthesis, stomatal conductance, chlorophyll fluorescence characteristics, chlorophyll content and growth were examined in Phragmites australis seedlings treated with various concentrations of combined salinity-alkalinity stress for 7 days. Combined salinity-alkalinity stress significantly decreased growth rate and chlorophyll content of Phragmites australis. The photosynthesis rates (Pn) were markedly inhibited under middle and high combined salinity-alkalinity stress. The value of F V /F M decreased when reed seedlings were stressed by high salinity-alkalinity treatment. The comprehensive photosynthesis performance index (PI ABS) and the electron transport (ET/RC) were sensitive to salinity-alkalinity stress, and showed a significant decrease under high salinity-alkalinity stress. These results demonstrated the mechanism of combined saline-alkaline stress on the photosystem II of reed. Decreased photosynthesis rate under low salinity-alkalinity condition is associated with the increase of stomatal closure, while decreased photosynthesis rate under high salinity-alkalinity stress is mainly attributed to non-stomatal limitation. Additional research is needed to find management strategies for decrease the adverse effects of salinity-alkalinity stress on wetland plant.
Article
In salt marsh soils, germination and the first phases of seedling development often occur under dark, hypoxic or anoxic, and saline conditions. Spartina alterniflora and Phragmites australis seedling development were examined under covaried oxygen and salinity concentrations in growth chamber experiments. First, the effects of oxygen and salinity on seedling development were tested in the dark, using a 5 5 factorial design. Oxygen did not affect P. australis plumule growth at oxygen concentrations from 21 down to 2.5%. Plumules were longer at ≤10 than at ≥25 g NaCl/L. Root growth was maximum in 21% oxygen, at ≤10 g NaCl/L and reduced at all salinities in oxygen concentrations ≤10%. No plumule or root growth occurred under anoxia. Salinity did not affect S. alterniflora mesocotyl emergence, which was fastest in anoxia and hypoxia. Mesocotyls did not emerge from the spikelet in 21% oxygen. In contrast, plumule growth was fastest in 21% oxygen, but was inhibited in anoxia. Under low oxygen and high salinity both plumule and root elongation were reduced. Coleoptile and mesocotyl elongation were greatest in 2.5 and 5% oxygen, and shortest in anoxia. The percentage of mesocotyls elongating was also highest in 2.5% oxygen. Rapid S. alterniflora coleoptile and mesocotyl elongation in anoxia enables its seedlings to escape the impact of the stressful environment where its seeds can germinate, but the seedlings could not survive otherwise. In separate experiments, S. alterniflora seeds were germinated and the seedlings grown in the dark for 10 d, then exposed to light for 4 d. Prior to illumination the seedlings did not develop beyond the stage of a small plumule enclosed in the coleoptile. Within 48 h of illumination in the presence of CO2, roots emerged and the plumule elongated inside the coleoptile at salinities up to 40 g NaCl/L, while the external environment remained anoxic. Without CO2, plumule growth and root development did not occur. This suggested oxygen was produced inside the coleoptile by the photosynthesizing plumule, and triggered root development. The ability of S. alterniflora seedlings to continue development under external anoxia and high salinity gives that species a competitive advantage over P. australis in high salinity and/or poorly drained marshes.
Article
Gradients in oxygen availability and salinity are among the most important environmental parameters influencing zonation in salt marsh communities. The combined effects of oxygen and salinity on the germination of two salt marsh grasses, Spartina alterniflora and Phragmites australis, were studied in growth chamber experiments. Germination of both species was initiated by emergence of the shoot and completed by root emergence. Percentage S. alterniflora germination was reduced at high salinity (40 g NaCl/L) and in decreased oxygen (5 and 2.5%). In 0% oxygen shoots emerged, but roots did not. P. australis germination was reduced at a lower salinity (25 g NaCl/L) than S. alterniflora, and inhibited at 40 g NaCl/L and in anoxia. However, a combination of hypoxia (10 and 5% O2) and moderate salinity (5 and 10 g NaCl/L) increased P. australis germination. When bare areas in the salt marsh are colonized, the different germination responses of these two species to combinations of oxygen and salt concentrations are important in establishing their initial zonation. In high salinity wetlands S. alterniflora populates the lower marsh and P. australis occupies the high marsh at the upland boundary.
Article
Water table is one of the factors controlling the distribution and performance of Phragmites communis Trin. Dense stands normally lose more water through evapotranspiration than is supplied by rain. However, Phragmites grows in a wide range of regimes, and is limited, in Britain, more by nutrient status than by water depth at its wetter limit, and more by competition than by water shortage at its drier limit. Rhizome level and the level of bud initiation are affected by water table, but performance of aerial shoots need not be affected by this, in the ordinary water regimes. Soil aeration, in the range found in East Anglia, does not affect performance, but if cut (or broken) reed is flooded, thus impeding aeration, performance decreases. Once a seasonal pattern of water-level fluctuations is established, departure from this (causing drying in a season the stand is normally flooded) disturbs the growth cycle and lowers the yield.
Article
Each year, a young population of shoots of Phragmites communis Trin. shows a positively skew height/number curve. In a dominant stand the mode moves to the right during development, and the final growth curve is negatively skew. All fully developed shoots flower, but some buds are always formed too small to permit flowering; many shoots remain under-developed in unfavourable habitats; in bad weather potential flowering shoots may fail to develop through to flowering, and short inflorescences may fail to emerge and flower. The width of the emergent bud determines its potential number of nodes, and its potential for flowering. The first cause of serious harm to young shoots is frost. Frost typically kills the early, potentially large, shoots, and gives a shorter and denser final population. Caterpillar damage comes rather later, and is more localized. With fewer replacement shoots, and less time in which these can mature, the final crop can be seriously reduced. Internal competition is serious only after the end of the emergence period, and as small and late-emerging shoots are affected most, there is little effect on performance or flowering.
Article
Restoration of riparian plant communities on bare soil requires germination of seeds and establishment of seedlings. However, species that are present in the soil seed bank do not always establish in the vegetation. Temperature, moisture conditions and soil type could play a major role in the establishment of riparian plant communities, through impacting seedling emergence. We studied the effects of temperature, combinations of temperature and moisture conditions, and soil type on seedling emergence and mortality of perennial reeds (Typha latifolia and Phragmites australis) and annual or biannual pioneer species (Senecio congestus, Rumex maritimus and Chenopodium rubrum). The responses to the environmental conditions were species-specific and resulted in context-dependent differences in proportions of species emerging from the soil seed bank. Typha latifolia and S. congestus preferred wet or very wet conditions, C. rubrum and R. maritimus preferred dry to very dry conditions. Phragmites australis was able to establish under all conditions. Both cold and very dry conditions resulted in low emergence and survival, which was not fully compensated for when conditions became favorable again. Senecio congestus, R. maritimus and C. rubrum benefitted from secondary seedling emergence when, after a very dry period, the weather became very wet again, while T. latifolia and P. australis remained absent. When the conditions remained wet, more seedlings emerged from sand than from clay. However, when the soil was drying out, fewer seedlings emerged from sand than from clay. We propose that using information on plant species-specific responses to abiotic environmental conditions during germination, emergence and establishment can help to restore different target riparian plant communities.
Article
From abundant circumstantial evidence it had already been suggested that on Wicken Fen "litter" communities (Molinietum) had been produced by yearly autumn cutting of fen vegetation for cattle bedding, and that the other main crop on the fen (Cladio-Molinietum) was determined by the customary 3- or 4-yearly cutting. Field experiments carried on since 1927, and some observations since 1923, support this view strongly, and thus the author's view that these communities are stages in deflected successions. After 12 years of annual autumn cropping an area of Cladio-Molinietum had developed most of the features characteristic of Molinietum, and similar changes were demonstrated to take place more slowly with cropping at longer time intervals, whilst with 4-yearly cropping the Cladio-Molinietum seemed unaffected. The results are based upon field-notes of areas each 20m. square, with remapping and dry weight analyses of the sorted crop from permanent metrequadrats. The different methods support and supplement one another strongly. The details of the change from Cladio-Molinietum towards Molinietum involved the diminution or disappearance of Caldium and associated "mixed-sedge" species such as Eupatorium cannabinum, Lythrum Salicaria, Peucedanum palustre and Salix repens, var. fusca, with the appearance and spread, or merely the extension of the species characteristic of "litter", such as Molinia itself, Carex panicea, Juncus obtusiflorus, Scabiosa succisa, Valeriana dioica, Cirsium anglicum, etc. To some extent the reasons for these changes can be found in the plants themselves; thus the species typical of Cladio-Molinietum are tall, and those of Molinietum dwarfer. The latter therefore benefit by removal of competition of the taller species (the question of complementary requirements or interdependence probably does not affect most of the species). The Cladium is susceptible to frequent cutting because it has long-lived evergreen leaves, whilst Molinia, which is unaffected by autumn cutting, has annual shoots shed from the food-storing stem bases. Carex panicea appears particularly susceptible to competition. A quadrat in vegetation brought by yearly cutting to a condition between Cladio-Molinietum and Molinietum, but left uncut since about 1918, has shown how changes towards a "litter" character are reversible when cutting is suspended. Carex panicea disappears again, Molinia is reduced and the dominance of Cladium is re-established. Experimental areas in Molinietum cut at intervals of 1, 2, 3 and 4 years since 1927 have shown no very marked alteration in composition, although there has been some diminution of species characteristic of "litter" in the areas cut least frequently. In both Cladio-Molinietum and Molinietum there are very large variations in the crop from one year to another, but although these are probably caused by seasonal differences in climate, it is difficult to connect them with any specific climatic indices. Lastly we may note that the results call attention to the value of the method of dry weight analysis of the sorted crop from permanent metrequadrats, in recording changes in the amounts of species of high frequency, such as the dominants and sub-dominants. This field descriptions fail almost entirely to do, and remapping of the quadrats does incompletely. The field descriptions, on the other hand, record changes in species of lowest frequency which are missed by the other two methods.
Chapter
Für die pflanzliche Stoffproduktion spielt das „Licht“ neben den klimatischen Faktoren (Temperatur, Niederschlag, Luftfeuchtigkeit, Wind usw.) eine entscheidende Rolle. Nur jener Teil des elektromagnetischen Spektrums zwischen 400 und 700 nm Wellenlänge, der tatsächlich vom photosynthetischen Apparat der Chloroplasten in den Pflanzenzellen absorbiert wird, kann auch genützt und in chemische Energie umgewandelt werden.
Chapter
Um die Vegetation eines geographischen Raums beschreiben und analysieren zu können, bedient man sich floristischer, physiognomischer und funktionaler Merkmale. Sie sind die Bausteine von Pflanzengemeinschaften (Vegetationstypen, Vegetationseinheiten, Phytozönosen).
Chapter
One of the earliest, and most extensive, collaborative salt marsh restorations in New England was launched east of the Port of Galilee, in Narragansett, Rhode Island, in the early 1990s (fig. 20.1). Once part of the largest coastal wetland complex in the state, by the 1950s these wetlands had been extensively altered by breachway construction, deposition of dredged material, and construction of docks, commercial facilities, houses, and roads (Lee 1980). In 1956, construction of the four-lane Galilee Escape Route, with only one 75 centimeter diameter culvert, severely restricted tidal flow from Bluff Hill Cove to the state-owned Galilee Bird Sanctuary and impounded freshwater runoff there. Over the next forty years, more than 80 percent of the 40 hectare Sanctuary salt marsh shifted from predominantly Spartina (cordgrass) to a mix of Phragmites australis (common reed) and freshwater or upland shrubs and trees (fig. 20.1).
Article
Sea-level rise associated with climate change presents a major challenge to plant diversity and ecosystem service provision in coastal wetlands. In this study, we investigate the effect of sea-level rise on benthos, vegetation, and ecosystem diversity in a tidal wetland in west Wales, the UK. Present relationships between plant communities and environmental variables were investigated through 50 plots at which vegetation (species and coverage), hydrological (surface or groundwater depth, conductivity) and soil (matrix chroma, presence or absence of mottles, organic content, particle size) data were collected. Benthic communities were sampled at intervals along a continuum from saline to freshwater. To ascertain future changes to the wetlands' hydrology, a GIS-based empirical model was developed. Using a LiDAR derived land surface, the relative effect of peat accumulation and rising sea levels were modelled over 200 years to determine how frequently portions of the wetland will be inundated by mean sea level, mean high water spring and mean high water neap conditions. The model takes into account changing extents of peat accumulation as hydrological conditions alter.