Evaluation of AFLP markers to reveal genetic diversity in Typha

We investigated to what extent DNA-markers can assist species determination in the genus Typha. A set of AFLP markers was used to discriminate samples of the species Typha latifolia and Typha angustifolia collected in Flanders (North Belgium). The T. latifolia samples formed a compact cluster while the T. angustifolia samples were divided into smaller groups. It was not clear whether interspecific hybrids or higher levels of diversity present in the T. angustifolia dataset could account for this. As in previous surveys, using isozyme and VNTR markers, AFLP markers revealed an almost complete lack of genetic variation in Flemish T. latifolia. Despite the low degree of diversity, a significant level of genetic differentiation was found between the T. latifolia samples originating from different river basins. Whether this differentiation has any ecological relevance remains to be investigated. The methodology applied was not able to detect clonal reproduction in T. latifolia. Probably, the low levels of diversity present in this species can account for this, indicating that the usefulness of the methodology applied depends on the level of diversity present in the species studied.     

Long-term competitive displacement of Typha latifolia by Typha angustifolia in a eutrophic lake

This study follows the outcome of long-term competition between a broad-leaved and a narrowleaved Typha species, T. latifolia and T. angustifolia respectively, in a eutrophic lake. The lake was bordered by a zone of T. latifolia, at one location interrupted by a T. angustifolia stand. Distributional changes of the T. angustifolia stand and the adjacent zone of T. latifolia were measured on aerial photographs (13 years) and along ground-level transects (6 years). A second stand of T. angustifolia was established with transplanted ramets within a formerly homogeneous zone of T. latifolia, and displacement between the two species was measured along ground-level transects after 6 years. Differences between the species in shoot performance were investigated to help explain the relative competitive abilities of the two Typha species. T. angustifolia expanded at the expense of T. latifolia at all water depths where both species occurred, except in very shallow water. Expansion rates suggest that T. angustifolia was not affected by the presence of T. latifolia in water depths exceeding 0.25 m. The Typha species were significantly negatively associated according to rank correlations of shoot densities, and changes of shoot densities, along the transects. These results suggest that T. angustifolia is competitively superior to T. latifolia, contradicting earlier studies. The higher competitive ability of T. angustifolia is consistent with its having taller shoots and a higher standing crop in early summer. Further, shoot height distributions indicated a closer integration of shoot emergence during spring in T. angustifolia than in T. latifolia. A high leaf area/shoot weight ratio suggest that T. latifolia may instead be relatively fast-growing, achieving competitive superiority over narrower-leaved Typha species during a transient period after simultaneous seedling establishment.     

Regional differences in the abundance of native, introduced, and hybrid Typha spp. in northeastern North America influence wetland invasions

In northeastern North America, an important wetland invader is the cattail Typha × glauca, a hybrid of native Typha latifolia and introduced Typha angustifolia. Although intensively studied in localized wetlands around the Great Lakes, the distributions of the hybrid and its parental species across broad spatial scales are poorly known. We obtained genotypes from plants collected from 61 sites spanning two geographical regions. The first region, near the Great Lakes and St. Lawrence Seaway (GLSL), has experienced substantial Typha increases over the last century, whereas more modest increases have occurred in the second region across Nova Scotia, New Brunswick, and Maine (NSNB). We found that hybrids predominate in the GLSL region, thriving in both disturbed and undisturbed habitats, and are expanding at the expense of both parental species. In contrast, the native T. latifolia is by far the most common of the three taxa across all habitat types in the NSNB region. We found no evidence that the formation of backcrossed and advanced-generation hybrids is limited by the reproductive barriers that are evident in F₁ hybrids. However, although backcrossed individuals arise in both regions, they are much less common than F₁ hybrids, which may explain why the parental species boundary remains. We conclude that F₁ hybrids are playing a key role in the invasion of wetlands in the GLSL region, whereas their low frequency in the NSNB region may explain why Typha appears to be much less invasive further east. An improved understanding of these contrasting patterns of distribution is necessary before we can accurately predict future wetland invasions.     

Microsatellite loci isolated from narrow‐leaved cattail Typha angustifolia

We present 11 dinucleotide microsatellite DNA loci isolated from the narrow‐leaved cattail (Typha angustifolia) and describe conditions for their amplification. The PCR primers were tested on at least 20 individuals of Typha angustifolia and T. latifolia from two Ukrainian populations per species. The primers amplify loci with relatively high numbers of alleles (averaging 7.22 and 4.95 alleles per locus in T. angustifolia and T. latifolia, respectively), and polymorphic information content (averaging 0.61 and 0.46 in T. angustifolia and T. latifolia, respectively).     

Allelopathy as a mechanism for the invasion of <Emphasis Type="Italic">Typha angustifolia</Emphasis>

The direct competitive effects of exotic plants on natives are among the leading causes of plant extinctions worldwide. Allelopathy, one type of direct plant competition, has received relatively little research, particularly in aquatic and wetland systems, even though allelopathy can be a potent mechanism through which plant communities are structured. Typha angustifolia (narrow-leaved cattail) is an invasive exotic plant in North America that often forms monocultures in disturbed wetlands and is more invasive than native members of its genus. We tested whether T. angustifolia was allelopathic and whether it produced different biochemicals than a native congener by growing it with the native bulrush Bolboschoenus fluviatilis (river bulrush) in soil with and without activated carbon and by qualitatively and quantitatively comparing soluble phenolics produced in the roots of T. angustifolia and the native Typha latifolia (broad-leaved cattail). T. angustifolia had a strong allelopathic effect on B. fluviatilis, reducing the longest leaf length and root, shoot, and total biomass of B. fluviatilis. When the allelopathy of T. angustifolia was ameliorated by activated carbon, however, longest leaf length, ramet number, root biomass, shoot biomass, and total biomass of T. angustifolia were greatly reduced due to resource competition with B. fluviatilis. Furthermore, T. angustifolia produced different, but not more, soluble phenolics than T. latifolia suggesting that the identity of the phenolics is different between the two species rather than the concentrations. The allelopathic effects of T. angustifolia on a North American native wetland plant and its production of root biochemicals that appear to differ from those produced by a native congener are consistent with the possibility that T. angustifolia may use a novel allelochemical in its invasion of North American wetlands.     

Root aerobic respiration and growth characteristics of three Typha species in response to hypoxia

The responses of root aerobic respiration to hypoxia in three common Typha species were examined. Typha latifolia L., T. orientalis Presl, and T. angustifolia L. were hydroponically cultivated under both aerobic and hypoxic growth conditions to measure root oxygen consumption rates. Hypoxia significantly enhanced the root aerobic respiration capacity of the two deep-water species, T. orientalis and T. angustifolia, while it did not affect that of the shallow-water species, T. latifolia. T. angustifolia increased its root porosity and root mass ratio, while T. latifolia increased its root diameter under the hypoxic growth conditions. The relative growth rates in biomass of T. orientalis and T. angustifolia were 59 and 39% higher, respectively, under the hypoxic growth conditions than under the aerobic growth conditions. In contrast, that of T. latifolia did not differ between the two conditions. In T. orientalis and T. angustifolia, enhanced root aerobic respiration rates under the hypoxic growth conditions would have increased the nutrient uptake, and thus higher relative growth rates were obtained. For the deep-water species, T. orientalis and T. angustifolia, the root aerobic respiration capacity was enhanced, probably in order to maintain the generation of respiratory energy under hypoxia.     

Putative source of the invasive Sirex noctilio fungal symbiont, Amylostereum areolatum, in the eastern United States and its association with native siricid woodwasps

Two genotypes of the fungal symbiont Amylostereum areolatum are associated with the invasive woodwasp Sirex noctilio first found in North America in 2004. S. noctilio is native to Europe but has been introduced to Australasia, South America and Africa where it has caused enormous losses in pine plantations. Based on nucleotide sequence data from the intergenic spacer region (IGS) of the nuclear ribosomal DNA, the A. areolatum genotypes found in North America are most similar to genotypes found in Europe, and not to genotypes from the southern hemisphere. Although two IGS strains of A. areolatum were found in North America it cannot be stated whether A. areolatum was introduced to North America from Europe once or twice based on our study. Genetic groupings formed by sequencing data were in most cases supported by vegetative compatibility groups (VCGs). Other siricid woodwasp species in the genus Sirex are native to North America. The North American native Sirex edwardsii emerging from the same tree as S. noctilio carried the same strain of A. areolatum as S. noctilio. The North American native Sirex sp. ‘nitidus’ collected outside the geographical range of S. noctilio carried a unique strain within A. areolatum. Our findings of A. areolatum in the native North American species, S. sp. ‘nitidus’, contrast with the previous view that A. areolatum was not present in North America before the accidental invasion of S. noctilio.     

Applying and testing a predictive vegetation model to management of the invasive cattail, Typha angustifolia L., in an oligohaline tidal marsh reveals priority effects caused by non-stationarity

Effective tidal marsh restoration requires predictive models that can serve as planning and design tools to answer basic questions such as which, if any, plant species will colonize a proposed restoration site. To develop such a tool, a predictive model of oligohaline tidal marsh vegetation was developed from reference marshes in the Skagit River Delta (Washington, USA) and applied to a 1.1-ha restoration treatment site. Probability curves for the elevational distributions of common marsh species were generated from RTK-GPS point samples of reference tidal marshes. The probability curves were applied to a LIDAR-derived digital elevation model to generate maps predicting the occurrence probability of each species within treatment and control sites. The treatment and control sites, located within a recently restored area that had been diked but never completely drained, were covered by a mono-culture of non-native Typha angustifolia L. (narrow-leaf cattail) growing 40–60 cm lower in elevation than in the reference marsh. The T. angustifolia was mowed repeatedly in the treatment site to allow colonization by predicted native marsh species. Four years after mowing, T. angustifolia was replaced on 60 % of the treatment site by native sedges (Carex lyngbyei, Eleocharis palustris), consistent with the predictive vegetation model; the control site remained covered by T. angustifolia. The mowing experiment confirmed that pre-emptive competition from T. angustifolia was preventing vegetation recovery in the restoration site following dike removal, and implied that some vegetation species may be refractory to environmental change, such as dike removal or sea-level rise, because of differences in recruitment and adult niches.     

Growth strategy of an emergent macrophyte, Typha orientalis Presl, in comparison with Typha latifolia L. and Typha angustifolia L.

The growth strategy of an emergent plant, Typha orientalis Presl, was examined in experimental ponds in comparison with two other Typha species distributed in Japan, Typha latifolia L. and Typha angustifolia L. T. orientalis showed the greatest ability of vegetative reproduction at the expense of growth in height. T. orientalis started to produce new ramets earlier than T. latifolia and T. angustifolia. These results suggest that T. orientalis should be a rather pioneer-like species and would be restricted to disturbed habitats.     

Analysis of pollen proteins of Typha species in relation to identification of hybrids

Hybridization studies have been carried out with Typha angustifolia, T. latifolia, T. shuttleworthii and T. minima. All combinations, except those with T. minima, were successful. The hybrid $\text{T. latifolia (♀) × T. angustifolia (♂)}$ has been obtained after 5 attempts involving hundreds of pollinations. The pollen proteins of the parental as well as the F₁ generation have been examined by isoelectrofocusing (IEF). The proteins from each species and each hybrid form displayed a distinct and constant pattern. The pollen protein profile thus represents a new, quite easily accessible character by which F₁ hybrids between the species studied can be unequivocally identified, whereas the morphological criteria described in the literature to distinguish intermediate forms is insufficient for this purpose.     

Effects of size and growth rate on vegetative reproduction in Typha

Summary The objective of this study was to separate the effects of plant biomass and growth rate on vegetative reproduction in two species of cat-tail, Typha latifolia and T. angustifolia. Replicate clones of both species were grown under conditions of 100%, 42%, 24%, and 9% full sunlight with harvests at 41, 70, and 91 days after shading. T. angustifolia produced most of its vegetative offspring before the first harvest and increased biomass over the remainder of the experiment by increasing the size of its ramets. In contrast, T. latifolia produced vegetative offspring gradually throughout the experiment adding new ramets only after existing clones were of mature size. As a result of these differences in the cloning process, T. angustifolia showed little correlation between vegetative reproduction and clone size while T. latifolia showed a strong correlation between gegetative reproduction and clone size at the three highest light intensities. Growth rates, average clone size and vegetative reproduction were all reduced by reductions in light intensity for both species. However, no effect of growth rate on the relationship between clone size and vegetative reproduction in T. latifolia could be detected. T. latifolia showed greater survivorship and more biomass production under 9% light than T. angustifolia indicating a greater shade tolerance.     

<Emphasis Type="Italic">Spartina versicolor</Emphasis> Fabre: Another case of <Emphasis Type="Italic">Spartina</Emphasis> trans-Atlantic introduction?

Intercontinental introductions are widespread in the genus Spartina, with important ecological and evolutionary consequences. The native or introduced status of Spartina species is then critical with regard to biodiversity assessment, especially for vulnerable Mediterranean coastline ecosystems. Spartina versicolor was first recorded in southern France in 1849, then successively in various places on the European and North-African Mediterranean and Atlantic coasts. This species is considered to be either a European native or an invasive species introduced from North America which has a high morphological similarity to the Atlantic American species Spartina patens. We performed extensive sampling of S. versicolor in Europe and North Africa (from natural populations and herbarium collections) and compared these samples to other European and American Spartina species (including S. patens). Chromosome counts were reported for the first time and revealed that S. versicolor is tetraploid (2n = 4x = 40). Phylogenetic analyses based on chloroplast and nuclear ribosomal DNA sequences did not reveal any molecular variation within S. versicolor. In this species, a single haplotype, that is identical to one haplotype of S. patens, was found in the four chloroplast and the nuclear ribosomal ITS regions investigated. In addition, simple sequence repeat markers were used and revealed a low level of genetic diversity within S. versicolor, suggesting that the introduction of S. versicolor occurred from a narrow genetic pool of S. patens from North America.     

Typha glauca Godron and its parental plants in Poland: taxonomic characteristics

Natural interspecific hybridization between Typha latifolia L. and Typha angustifolia L. was analyzed by morpho-anatomical and molecular methods to determine whether the hybrid Typha glauca Godr. is present in Poland and to identify the best diagnostic traits for its identification. Eighty-three samples of the Typha species were collected. Nine random amplified polymorphic DNA (RAPD) primers provided 12 fragments specific for T. angustifolia and eight fragments specific for T. latifolia. DNA of all sampled individuals was analyzed with 20 diagnostic RAPD markers. The morpho-anatomical variability of T. glauca F₁ was found to be quite similar to that observed in parental plants. All of the 41 traits examined in the hybrids overlapped with those observed in the parents, however, the hybrids were visibly closer to T. angustifolia than to T. latifolia. The most discriminate characteristics were the length and pedicel width, as well as the epidermal cell thickness located above vascular bundles in leaf blades. Moreover, preliminary observations of seed sculpture showed that the length of testa cells could also be used to identify T. glauca. Clusters and the hybrid index (for molecular and morphological data) were highly coincident and support the hybridization hypothesis.     

Foliar pathogens of Populus angustifolia are consistent with a hypothesis of Beringian migration into North America

Populus angustifolia, the narrowleaf cottonwood, is considered one of two native species of Populus section Tacamahaca restricted to western North America. Efforts to construct a definitive phylogeny of Populus spp. are complicated by ancient hybridization, but some phylogenetic analyses suggest P. angustifolia is more closely related to Asian congeners than to Populus trichocarpa, the other species of Populus section Tacamahaca in western North America. Because hosts and their obligate symbionts can display parallel phylogeographic patterns, we evaluated the possibility of a Beringian migration into North America by an Asian ancestor of P. angustifolia by determining the distributions, host preferences, and, in some cases, closest phylogenetic relatives of fungal leaf pathogens of P. angustifolia. Phyllactinia populi, a common foliar pathogen on Populus spp. in Asia but unknown on P. trichocarpa, was found on P. angustifolia in multiple sites. Mycosphaerella angustifoliorum, also unknown on P. trichocarpa, was commonly collected on P. angustifolia. Conversely, many common foliar pathogens of P. trichocarpa in western North America were not found on P. angustifolia; only Melampsora×columbiana and Drepanopeziza populi were common to both Populus species. Phylogenetic analyses revealed that M. angustifoliorum was not part of the diversification of Mycosphaerella on Populus that includes all other Mycosphaerella species on Populus in North America: Mycosphaerella populicola, Mycosphaerella populorum, M. sp. 1, and M. sp. 2. The latter two undescribed species represent a newly discovered diversification of M. populorum in western North America. Overall, the leaf pathogen community of P. angustifolia is consistent with a Beringian migration into North America by the ancestor of P. angustifolia.     

Morphological adaptations of emergent plants to water flow: a case study with Typha angustifolia, Zizania latifolia and Phragmites australis

1. Water velocity plays an important role in shaping plant community structure in flowing waters although few authors have yet attempted to explain the adaptation of plants to flow. 2. We aimed to test two hypotheses, that: (i) some emergent macrophytes reconfigure their shoot distribution in fast currents and form clumps, and (ii) the shape and morphology of such clumps minimises drag caused by the current. The study focuses on three emergent macrophytes that co‐occur along a gradient of water velocity. 3. The species showed a clear zonation in response to water depth and current velocity. Phragmites australis occupied shallower and more slowly flowing water than Typha angustifolia and Zizania latifolia, which had similar preferences. 4. Both T. angustifolia and Z. latifolia shoots were more clumped at high velocity, whereas they were more randomly distributed at low flow or in stagnant water. Because of the low shoot density, water flowed more easily through T. angustifolia clumps, whereas Z. latifolia clumps had a high shoot density and large amounts of trapped litter, causing stagnant water in the centre of the clump. The clumps of Z. latifolia with a high density of shoots were longer and narrower than T. angustifolia clumps. Phragmites australis was less tolerant of flow than the other two species and large amounts of litter trapped in the clumps impaired flow. 5. The shoot distribution of both T. angustifolia and Z. latifolia is reconfigured at high flow and this minimises drag on the clumps.     

Comparative phylogeography of two colonial ascidians reveals contrasting invasion histories in North America

Surveys of genetic structure of introduced populations of nonindigenous species may reveal the source(s) of introduction, the number of introduction events, and total inoculum size. Here we use the mitochondrial cytochrome c oxidase subunit 1 (COI) gene to explore genetic structure and contrast invasion histories of two ecologically similar and highly invasive colonial ascidians, the golden star tunicate Botryllus schlosseri and the violet tunicate Botrylloides violaceus, in their global and introduced North American ranges. Haplotype and nucleotide diversities for B. schlosseri were significantly higher than for B. violaceus both globally (h = 0.872; ?? = 0.054 and h = 0.461; ?? = 0.007, respectively) and in their overlapping North American ranges (h = 0.874; ?? = 0.012 and h = 0.384; ?? = 0.006, respectively). Comparative population genetics and phylogenetic analyses revealed clear differences in patterns of invasion for these two species. B. schlosseri populations on the west and east coasts of North America were seeded from the Pacific and Mediterranean regions, respectively, whereas all North American B. violaceus populations were founded by one or more introduction events from Japan. Differences in genetic structure of invasive populations for these species in North America are consistent with their contrasting probable introduction vectors. B. schlosseri invasions most likely resulted from vessel hull fouling, whereas B. violaceus was likely introduced as a ??fellow traveler?? in the shellfish aquaculture trade.     

Typha for paludiculture—Suitable water table and nutrient conditions for potential biomass utilization explored in mesocosm gradient experiments

Drainage has turned 650,000 km² of peatlands worldwide into greenhouse gas sources. To counteract climate change, large‐scale rewetting is necessary while agricultural use of rewetted areas, termed paludiculture, is still possible. However, more information is required on the performance of suitable species, such as cattail, in the range of environmental conditions after rewetting. We investigated productivity and biomass quality (morphological traits and tissue chemical composition) of Typha angustifolia and Typha latifolia along gradients of water table depth (−45 to +40 cm) and nutrient addition (3.6–400 kg N ha⁻¹ a⁻¹) in a six‐month mesocosm experiment with an emphasis on their high‐value utilization, e.g., as building material, paper, or biodegradable packaging. Over a wide range of investigated conditions, T. latifolia was more productive than T. angustifolia. Productivity was remarkably tolerant of low nutrient addition, suggesting that long‐term productive paludiculture is possible. Low water tables were beneficial for T. latifolia productivity and high water tables for T. angustifolia biomass quality. Rewetting will likely create a mosaic of different water table depths. Our findings that the yield of T. angustifolia and tissue chemical composition of T. latifolia were largely unaffected by water table depth are therefore promising. Depending on intended utilization, optimal cultivation conditions and preferable species differ. Considering yield or diameter, e.g., for building materials, T. latifolia is generally preferable over T. angustifolia. A low N, P, K content, high Si content and high C/N‐ratio can be beneficial for processing into disposable tableware, charcoal, or building material. For these utilizations, T. angustifolia is preferable at high water tables, and both species should be cultivated at a low nutrient supply. When cellulose and lignin contents are relevant, e.g., for paper and biodegradable packaging, T. angustifolia is preferable at high water tables and both species should be cultivated at nutrient additions of about 20 kg N ha⁻¹ a⁻¹.     

Can enemy release explain the invasion success of the diploid <Emphasis Type="Italic">Leucanthemum vulgare</Emphasis> in North America?

Enemy release is a commonly accepted mechanism to explain plant invasions. Both the diploid Leucanthemum vulgare and the morphologically very similar tetraploid Leucanthemum ircutianum have been introduced into North America. To verify which species is more prevalent in North America we sampled 98 Leucanthemum populations and determined their ploidy level. Although polyploidy has repeatedly been proposed to be associated with increased invasiveness in plants, only two of the populations surveyed in North America were the tetraploid L. ircutianum. We tested the enemy release hypothesis by first comparing 20 populations of L. vulgare and 27 populations of L. ircutianum in their native range in Europe, and then comparing the European L. vulgare populations with 31 L. vulgare populations sampled in North America. Characteristics of the site and associated vegetation, plant performance and invertebrate herbivory were recorded. In Europe, plant height and density of the two species were similar but L. vulgare produced more flower heads than L. ircutianum. Leucanthemum vulgare in North America was 17 % taller, produced twice as many flower heads and grew much denser compared to L. vulgare in Europe. Attack rates by root- and leaf-feeding herbivores on L. vulgare in Europe (34 and 75 %) was comparable to that on L. ircutianum (26 and 71 %) but higher than that on L. vulgare in North America (10 and 3 %). However, herbivore load and leaf damage were low in Europe. Cover and height of the co-occurring vegetation was higher in L. vulgare populations in the native than in the introduced range, suggesting that a shift in plant competition may more easily explain the invasion success of L. vulgare than escape from herbivory.     

Interspecific differences in radial oxygen loss from the roots of three <Emphasis Type="Italic">Typha</Emphasis> species

A comparison was made of the radial oxygen loss (ROL) from the roots of three Typha species, Typha latifolia L., Typha orientalis Presl and Typha angustifolia L., which resemble each other in morphology. ROLs were evaluated in the laboratory for seedlings of T. orientalis and T. angustifolia in order to compare them with the ROL value for T. latifolia obtained in our previous study. Measurements were conducted using the highly oxygen-sensitive anthraquinone radical anion as an oxygen indicator, which enabled us to simulate the natural conditions in which the oxygen released from the root is immediately consumed by the soil. Among the three Typha species, the ROL was the highest in T. angustifolia, followed by T. latifolia and T. orientalis. Illumination significantly enhances the ROL of T. orientalis, and this effect was also observed for T. latifolia in our previous study, whereas it did not affect the ROL of T. angustifolia. These results indicate that ROL differs significantly between species, even among members of the same genus that are similar in morphology.     

Russula velenovskyi new to Japan,with phylogenetic implications of Russula species between Japanese subalpine forests and Northern Europe

To compare morphological characters and phylogenetic placement between Japanese and European Russula, 32 specimens of 12 species were collected from Japanese subalpine forests and Northern Europe. Several sequences of nrDNA ITS region (ITS) of these Russula species were obtained. High homological similarities were shown between ITS sequences of several Russula samples collected from Japanese subalpine forests, Europe and North America. These facts show distribution of the same Russula species among these areas. From morphological observations and phylogenetic analyses, two same Russula species, R. velenovskyi, and R. decolorans are found in Japan, Europe and North America. Of these, R. velenovskyi collected from Mt. Fuji, Mt. Nyukasa and Mt. Tateshina in mountainous area of central Honshu is reported as a new Japanese record.