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Festuca Rubra (festuca + rubra)
Selected AbstractsVariation in the abundance of fungal endophytes in fescue grasses along altitudinal and grazing gradientsECOGRAPHY, Issue 3 2007Gustaf Granath Epichloë festucae, a common fungal symbiont of the genus Festuca (family Poaceae), can provide its host plant with protection against herbivores. However, infection might also be associated with a cost to its host plant. We examined the distribution of Epichloë festucae infection in natural populations of three fescue grasses, Festuca rubra, F. ovina and F. vivipara, on mountains in northern Sweden to determine whether infection frequency varied with reindeer Rangifertarandus grazing pressure and altitude. Two differently-scaled approaches were used: 1) infection frequency was measured at a local scale along ten elevational transects within a ca 400 km2 area and 2) infection frequency was measured on a regional scale along elevational transects on 17 mountains classified as having a history of high or low reindeer grazing pressure. Mean infection frequencies in F. rubra were 10% (vegetative tillers at a local scale), and 23% (flowering culms at a regional scale), and in F. ovina they were 13% (local scale) and 15% (regional scale). Endophyte infection frequency in F. vivipara, was, on average, 12% (local scale) and 37% (regional scale). In F. rubra, infection decreased significantly with increasing altitude at both the local and regional scale, and was positively correlated with grazing pressure. In F. ovina, an opposite trend was found at the regional scale: infection frequency increased significantly with increasing altitude, while no discernible distribution pattern was observed at the local scale. No elevational trends were observed in infection of F. vivipara. These patterns in the distribution of endophyte-infected grasses in non-agricultural ecosystems may be explained by both biotic (grazing) and abiotic factors (altitude). Differences in ecology and life history of the studied grass species may also be of importance for the different results observed among species. [source] Impact of elevated carbon dioxide on the rhizosphere communities of Carex arenaria and Festuca rubraGLOBAL CHANGE BIOLOGY, Issue 11 2007BARBARA DRIGO Abstract The increase in atmospheric carbon dioxide (CO2) levels is predicted to stimulate plant carbon (C) fixation, potentially influencing the size, structure and function of micro- and mesofaunal communities inhabiting the rhizosphere. To assess the effects of increased atmospheric CO2 on bacterial, fungal and nematode communities in the rhizosphere, Carex arenaria (a nonmycorrhizal plant species) and Festuca rubra (a mycorrhizal plant species) were grown in three dune soils under controlled soil temperature and moisture conditions, while subjecting the aboveground compartment to defined atmospheric conditions differing in CO2 concentrations (350 and 700 ,L L,1). Real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis methods were used to examine effects on the size and structure of rhizosphere communities. Multivariate analysis of community profiles showed that bacteria were most affected by elevated CO2, and fungi and nematodes to a lesser extent. The influence of elevated CO2 was plant dependent, with the mycorrhizal plant (F. rubra) exerting a greater influence on bacterial and fungal communities. Biomarker data indicated that arbuscular mycorrhizal fungi (AMF) may play an important role in the observed soil community responses. Effects of elevated CO2 were also soil dependent, with greater influence observed in the more organic-rich soils, which also supported higher levels of AMF colonization. These results indicate that responses of soil-borne communities to elevated CO2 are different for bacteria, fungi and nematodes and dependent on the plant type and soil nutrient availability. [source] Studying spatial and temporal dynamics of sward structure at low stocking densities: the use of an extended rising-plate-meter methodGRASS & FORAGE SCIENCE, Issue 4 2003O. Correll Abstract An extended rising-plate-meter method was used to study the spatial and temporal variability of the sward structure of extensively managed pastures over a grazing season. Two treatments of a long-term grazing experiment with heifers were investigated: extensive continuous grazing (EG) with a target sward height of 10 cm and intensive continuous grazing (IG) with a target sward height of 5 cm. Compressed sward height and related herbage mass (HM), dominant plant species and stage of development of phenology were determined at weekly or twice weekly intervals at fixed measuring points. The results demonstrated a strong variability in sward height and HM, especially on the EG treatment. The botanical composition of the standing herbage differed between treatments and between patches of different heights within the same treatment. In areas with a short sward, the herbage was predominantly composed of Agrostis capillaris, Festuca rubra and Trifolium repens. It was more evenly composed and also included taller growing species, such as Alopecurus pratensis and Galium mollugo, in areas with a tall sward. The area potentially available for reproductive development was high in the EG treatment and low in the IG treatment. The method employed proved suitable to provide a detailed description of the dynamics of the sward structure. [source] The effect of Calluna vulgaris cover on the performance and intake of ewes grazing hill pastures in northern SpainGRASS & FORAGE SCIENCE, Issue 4 2000K. Osoro The effect of the proportion of Calluna vulgaris cover on diet composition, intake and performance of sheep grazing hill vegetation communities in northern Spain is examined. A total of 591 non-lactating Gallega ewes grazed for five consecutive grazing seasons (June to September) on replicated plots of hill pastures (1700 m.a.s.l.) composed principally of Festuca, Agrostis, Nardus and Calluna spp. but with different proportions of Calluna vulgaris cover, either 0·3 (C0·3) or 0·7 (C0·7) of the total area. In 1 year, twenty-eight ewes suckling single lambs also grazed the plots. The mean stocking density over the 5 years was 8·7 ewes ha,1. On treatment C0·3, daily liveweight gains (33 g d,1) of non-lactating ewes were significantly (P < 0·001) greater than on treatment C0·7 (12 g d,1). Likewise in lactating ewes the difference in mean daily liveweight change was 40 g d,1 (,5 vs. ,45 g d,1 for C0·3 and C0·7 treatments respectively; P < 0·001). Liveweight gains of lambs were only 80,100 g d,1 from June to August and lambs only maintained live weight during August and September. The effect of lactational status on liveweight changes was not significant. Liveweight gains of non-lactating ewes increased significantly (P < 0·001) from the first to the last year of the experiment on both treatments. The composition of the diet was significantly affected by treatment (P < 0·001), with a higher proportion of grass species on the C0·3 treatment and a higher digestibility of the diet in the first half of the grazing season (P < 0·001). The proportion of C. vulgaris in the diet was significantly (P < 0·001) higher on the C0·7 treatment and increased significantly (P < 0·001) from July to September on both treatments. There were no significant differences in the composition of the diet selected by lactating and non-lactating ewes. The results demonstrate that on hill vegetation communities, in which the grass components (Festuca rubra, Agrostis capillaris, and Nardus stricta) cover at least 0·3 of the area and on which the preferred grass component (Festuca and Agrostis spp.) is maintained at a sward height of at least 2·5 cm, non-lactating ewes can increase their live weight and body condition, but this increase is influenced by the proportion and quantity of species of grass in the diet, which is affected in turn by the species of grass available and their nutritive quality. However, ewes suckling lambs were not able to maintain their live weight and body condition except when Calluna cover was 0·3 and grass height was more than 3·5 cm. It is concluded that these indigenous vegetation communities can be used in sheep production systems to complement the use of improved pastures at other times of year. In particular, they can be utilized during the non-lactating period (summer) to increase body condition before the beginning of the mating period in autumn. [source] Die Blattanatomie eines schnell und eines langsam wachsenden Grases in Abhängigkeit von der StickstoffversorgungJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2001G. Schulte auf'm Erley Leaf anatomy of a fast- and a slow-growing grass as dependent on nitrogen supply The grass species Lolium perenne and Festuca rubra, originating from habitats with differing N-availability, differ in their relative growth rate. This is mainly caused by the higher specific leaf area of L. perenne compared to F. rubra. The leaf anatomy of both species was further investigated. The species were raised in growth chambers under high and low N-supply. The higher specific leaf area of L. perenne (27 mm2 mg,1) in relation to F. rubra (14 mm2 mg,1) was mainly caused by a lower leaf density (0.23 vs. 0.33 mg mm,3). The level of N-supply influenced both leaf density and leaf thickness. The leaf volume of L. perenne comprised higher fractions of epidermis and lower fractions of mesophyll and intercellular space compared to F. rubra. However, the discrepancy in leaf density between the species could not be explained by anatomical differences. Under low N-supply, the leaves of both species had higher amounts of vascular bundles and fibre cells and lower amounts of intercellular space, which partly explained the higher density of the leaves. It is concluded, that thinner cell walls and higher amounts of cytoplasm cause the higher specific leaf area of L. perenne. Die Grasarten Lolium perenne und Festuca rubra, die auf Standorten mit unterschiedlicher N-Verfügbarkeit beheimatet sind, unterscheiden sich in ihrer relativen Wachstumsrate. Der Hauptgrund dafür liegt in der höheren spezifischen Blattfläche von L. perenne gegenüber F. rubra. Von beiden Arten wurde die Blattanatomie näher untersucht, nachdem sie in Klimakammern unter einer hohen und einer niedrigen N-Versorgungsstufe angezogen worden waren. Es zeigte sich, daß sich die höhere spezifische Blattfläche von L. perenne (27 mm2 mg,1) gegenüber F. rubra (14 mm2 mg,1) auf eine niedrigere Blattdichte zurückführen ließ (0,23 gegenüber 0,33 mg mm,3). Die Höhe der N-Versorgung beeinflußte sowohl die Blattdichte als auch die Blattdicke. Die Blätter von L. perenne hatten gegenüber denen von F. rubra höhere Volumenanteile an Epidermis und geringere Anteile an Mesophyll und Interzellularen. Die Unterschiede in der Blattdichte zwischen den Spezies ließen sich hierdurch nicht erklären. Unter niedriger N-Versorgung hatten die Blätter beider Arten höhere Anteile an Leit- und Faserbündeln und weniger Interzellularraum, was die höhere Blattdichte unter niedriger N-Versorgung teilweise erklärt. Es wird gefolgert, daß insgesamt dünnere Zellwände und mehr Cytoplasma die höhere spezifische Blattfläche von L. perenne verursachen. [source] Environmental stresses mediate endophyte,grass interactions in a boreal archipelagoJOURNAL OF ECOLOGY, Issue 2 2010Nora M. Saona Summary 1.,Both evolutionary theory and empirical evidence from agricultural research support the view that asexual, vertically transmitted fungal endophytes are typically plant mutualists that develop high infection frequencies within host grass populations. In contrast, endophyte,grass interactions in natural ecosystems are more variable, spanning the range from mutualism to antagonism and comparatively little is known about their range of response to environmental stress. 2.,We examined patterns in endophyte prevalence and endophyte,grass interactions across nutrient and grazing (from Greylag and Canada geese) gradients in 15 sites with different soil moisture levels in 13 island populations of the widespread grass Festuca rubra in a boreal archipelago in Sweden. 3.,In the field, endophyte prevalence levels were generally low (range = 10,53%) compared with those reported from agricultural systems. Under mesic-moist conditions endophyte prevalence was constantly low (mean prevalence = 15%) and was not affected by grazing pressure or nutrient availability. In contrast, under conditions of drought, endophyte prevalence increased from 10% to 53% with increasing nutrient availability and increasing grazing pressure. 4.,In the field, we measured the production of flowering culms, as a proxy for host fitness, to determine how endophyte-infected plants differed from uninfected plants. At dry sites, endophyte infection did not affect flowering culm production. In contrast, at mesic-moist sites production of flowering culms in endophyte-infected plants increased with the covarying effects of increasing nutrient availability and grazing pressure, indicating that the interaction switched from antagonistic to mutualistic. 5.,A concurrent glasshouse experiment showed that in most situations, the host appears to incur some costs for harbouring endophytes. Uninfected grasses generally outperformed infected grasses (antagonistic interaction), while infected grasses outperformed uninfected grasses (mutualistic interaction) only in dry, nutrient-rich conditions. Nutrient and water addition affected tiller production, leaf number and leaf length differently, suggesting that tillers responded with different strategies. This emphasizes that several response variables are needed to evaluate the interaction. 6.,Synthesis. This study found complex patterns in endophyte prevalence that were not always correlated with culm production. These contrasting patterns suggest that the direction and strength of selection on infected plants is highly variable and depends upon a suite of interacting environmental variables that may fluctuate in the intensity of their impact, during the course of the host life cycle. [source] Year-to-year variation in plant competition in a mountain grasslandJOURNAL OF ECOLOGY, Issue 1 2003Herben Summary 1We used a series of removal experiments to examine how species response to competition and climatic differences varied in three different years. We tested the interaction between removal of the dominant grass species, Festuca rubra, and year-to-year environmental variation in a mown mountain grassland. 2In each year, we quantified shoot frequency and above-ground biomass of all remaining plant species. Above-ground responses were tested both by analysis of covariance and by redundancy analysis with randomization tests of changes in total species composition. 3Analysis of above-ground biomass data showed that other species compensated for the removal of F. rubra biomass within 2 years and that the response in total biomass of the community did not differ among years in which the experiment was started. 4Multivariate tests showed that species composition changed as a result of the removal; grass biomass and frequency increased more than that of dicotyledons. However, response of species composition to removal of F. rubra was significantly different between onset years. Specific conditions in individual years thus affect the competitive ability of individual species in a non-additive way. 5Our results indicate that the year-to-year variation at the site has the potential to affect species coexistence and richness. As a consequence, year-to-year variation of climatic parameters may be an important driving factor in community dynamics and should be taken into account in studies of ecosystem response to climate. [source] Intensity and Importance of Competition for a Grass (Festuca rubra) and a Legume (Trifolium pratense) Vary with Environmental ChangesJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 12 2008Junyan Zhang Abstract How plant competition varies across environmental gradients has been a long debate among ecologists. We conducted a growth chamber experiment to determine the intensity and importance of competition for plants grown in changed environmental conditions. Festuca rubra and Trifolium pratense were grown in monoculture and in two- and/or three-species mixtures under three environmental treatments. The measured competitive variations in terms of growth (height and biomass) were species-dependent. Competition intensity for Festuca increased with decreased productivity, whilst competition importance displayed a humpback response. However, significant response was detected in neither competition intensity nor importance for Trifolium. Intensity and importance of competition followed different response patterns, suggesting that they may not be correlated along an environmental gradient. The biological and physiological variables of plants play an important role to determine the interspecific competition associated with competition intensity and importance. However, the competitive feature can be modified by multiple environmental changes which may increase or hinder how competitive a plant is. [source] Co-existing grass species have distinctive arbuscular mycorrhizal communitiesMOLECULAR ECOLOGY, Issue 11 2003P. Vandenkoornhuyse Abstract Arbuscular mycorrhizal (AM) fungi are biotrophic symbionts colonizing the majority of land plants, and are of major importance in plant nutrient supply. Their diversity is suggested to be an important determinant of plant community structure, but the influence of host-plant and environmental factors on AM fungal community in plant roots is poorly documented. Using the terminal restriction fragment length polymorphism (T-RFLP) strategy, the diversity of AM fungi was assessed in 89 roots of three grass species (Agrostis capillaris, Festuca rubra, Poa pratensis) that co-occurred in the same plots of a field experiment. The impact of different soil amendments (nitrogen, lime, nitrogen and lime) and insecticide application on AM fungal community was also studied. The level of diversity found in AM fungal communities using the T-RFLP strategy was consistent with previous studies based on clone libraries. Our results clearly confirm that an AM fungal host-plant preference exists, even between different grass species. AM communities colonizing A. capillaris were statistically different from the others (P < 0.05). Although grass species evenness changed in amended soils, AM fungal community composition in roots of a given grass species remained stable. Conversely, in plots where insecticide was applied, we found higher AM fungal diversity and, in F. rubra roots, a statistically different AM fungal community. [source] Defoliation and site differences influence vegetative spread in grasslandNEW PHYTOLOGIST, Issue 2 2002G. T. Barthram Summary ,,Plants spread vegetatively at rates that depend on both their own and their neighbours' traits. We tested hypotheses that such rates also interact with defoliation intensity and differ between sites. ,,Well-established monoculture patches (20 × 20 cm) of five grass species were arranged in plots so that every species patch had all the remaining species as neighbours. Sites were in central Scotland, UK, and at a drier location in eastern Scotland. Plots were cut at 3 cm (,short') or 6 cm (,tall'), either uniformly or in a chessboard pattern. ,,Invasiveness and resistance to invasion followed the transitive hierarchy, Agrostis capillaris > Festuca rubra > Lolium perenne = Holcus lanatus > Poa trivialis , except that P. trivialis strongly invaded H. lanatus at the damper, more fertile site. ,Tall' patches spread and intermixed most, independent of species. The effects of cutting neighbouring patches depended on both invading and invaded species' traits. ,,Thus, defoliation altered the relationships between species, as did differences between sites, influencing both the speed and direction of species replacement. [source] Mechanisms of resistance to invasion in a California grassland: the roles of competitor identity, resource availability, and environmental gradientsOIKOS, Issue 1 2007Meredith A. Thomsen Resistance to the invasion of exotic plants may sometimes result from the strong effects of a relatively small number of resident species. Understanding the mechanisms by which such species resist invasion could provide important insights for the management of invaded ecosystems. Furthermore, the individualistic responses of community members to resource availability and environmental gradients could drive spatial variation in resistance at the local to landscape scales. We tested the resistance of monoculture plots of three native perennial grasses from the California coastal prairie to the invasion of the European perennial grass Holcus lanatus. We also used a watering treatment that increased early summer water availability and a natural elevational gradient in resource availability and soil texture to evaluate how resident identity interacted with abiotic resistance to affect Holcus establishment. Two native species, Festuca rubra and Calamagrostis nutkaensis, exhibited strong resistance, correlated with their negative effects on light availability. A third native grass, Bromus carinatus var. maritimus, had either no effect or a weakly facultative effect on Holcus performance relative to bare plots. Water addition did not alter the resistance of these species, but the elevation gradient did. Holcus invasion increased with improving abiotic conditions towards the slope bottom in bare and Bromus plots, but invasion decreased towards the bottom in Calamagrostis plots, where better conditions favored competitive residents. These results support the idea that resistance to invasion can sometimes be due to a subset of native species, and that the resistance provided by even a single species is likely to vary across the landscape. Identifying the mechanisms by which species resist invasion could facilitate the selection of management strategies that at best increase, or at worst do not decrease, natural resistance. [source] Relationships between the genetic distance of Epichloë festucae isolates and the ergovaline and peramine contents of their Festuca rubra hostsANNALS OF APPLIED BIOLOGY, Issue 1 2010B.R. Vázquez-de-Aldana In semiarid grasslands of western Spain, plants of Festuca rubra are frequently infected by Epichloë festucae, an endophyte capable of producing the alkaloids ergovaline, toxic to mammals, and peramine, toxic to insects. The objectives of this paper were to estimate the variability in the content of ergovaline and peramine in plants of Festuca rubra from natural populations and to determine the relationship between the genetic distance among Epichloë strains and the alkaloid contents of plants infected by them. The results showed that a significant variation exits in the ergovaline and peramine contents of infected F. rubra plants, and that variation patterns are different for each alkaloid. Ergovaline content showed a significant variation between years. In contrast, most variation observed in the concentration of peramine occurred between populations. Mantel tests, constrained correspondence analysis (CCA) and generalised analysis of molecular variance (GAMOVA) all revealed a significant relationship between the genetic distances among 35 Epichloë isolates, and the differences in peramine content of their host plants. The relationship observed for ergovaline was more ambiguous. This indicates that plants infected by genetically close isolates of Epichloë festucae tend to be similar in terms of peramine content, while the ergovaline content of infected plants seems to be more dependent on external factors. The results of this study suggest that the selection of Epichloë festucae endophytes based on the alkaloid content of their host plants can be a successful strategy to select good or bad producers of peramine, but may not be a reliable method to detect fungal strains associated with particular ergovaline production profiles. [source] Assessing the dominance of Phleum pratense cv. climax, a species commonly used for ski trail restorationAPPLIED VEGETATION SCIENCE, Issue 2 2009Francis Isselin-Nondedeu Abstract Questions: (1) Are some species used for ski trail restoration too dominant to allow native species to re-establish? (2) What plant traits can be used to predict which species are good competitors? We tested the hypothesis that limited native species establishment on ski trails is caused by (1) the dominance of Phleum pratense cv. climax (PPC) and (2) the asymmetry of competitive interactions. Location: Sub-alpine area in the northern French Alps. Methods: PPC was cultivated outdoors over 2 years with 15 alpine species in a systematic design with high- and low-nutrient soil conditions. For each species relative survival, competitive performance and relationships with plant traits were measured. Results: PPC exerted strong dominance on most of its neighbouring species. Survival performance of Anthyllis vulneraria, Luzula sudetica and Lotus alpinus were dramatically reduced. Results of above-ground competition showed that species were trapped in asymmetric competition. Festuca rubra, Trifolium repens, Alchemilla xanthochlora, Trifolium pratense and Plantago alpina best counteracted PPC. Below-ground competition was more symmetric, particularly at the high nutrient level. Plant traits such as biomass, canopy size and specific leaf area were positively correlated with competitive performance of the species. Conclusion: The study has implications for the management of restored ski trails since PPC may hinder the establishment of native sub-alpine species. Consequently, recommendations should focus on (1) maintaining a low proportion or decreasing the proportion of PPC seeds in the revegetation mix and (2) reducing soil fertilization. Plant traits and competition experiments can help to predict changes in restored grasslands. [source] Using plant traits to compare sward structure and composition of grass species across environmental gradientsAPPLIED VEGETATION SCIENCE, Issue 1 2004M. Duru Abstract. Plant traits which may give an indication of a plant's strategy for nutrient acquisition and regeneration are known for numerous grassland species. This study aimed to establish whether there is any relationship between two plant traits: specific leaf area (SLA) and number of reproductive tillers, and sward structural characteristics which influence herbage intake by grazers (bulk density and digestibility, leaf:stem ratio). Comparison is made for nutrient-rich (Dactylis glomerata) and nutrient-poor (Festuca rubra) grass species. We hypothesized that these traits are responsive to environmental gradients and also act on the processes of the ecosystem. Both grasses were compared with two P-fertilizer rates in two localities (200 and 1300 m a.s.l.) which differed in their temperature:radiation ratios. For the vegetative phase SLA was well correlated with sward characteristics: D. glomerata, which has the higher SLA, has the lower bulk density and higher digestibility. The values of SLA and vegetation bulk density varied according to growing conditions (P-rate and temperature:radiation ratio), but the ranking of the species remained the same because the phenotypic plasticity that exists for plant traits was also observed for sward structure and composition. That suggested the possibility of grouping natural grassland species for their relevant characteristics for grazers according to SLA values. Over the reproductive phase, the proportion of stems was well correlated to the percentage of reproductive tillers. However, the percentage of reproductive tillers was a very plastic trait for both species, depending on the growing conditions, and resulting in a density-dependent effect, particularly for F. rubra. The species studied were too plastic and too similar in their regenerative strategy so that there is no unique relationship between percentage of reproductive tillers and stem proportion, regardless of the species and the growing conditions. The number of reproductive tillers is not a suitable plant trait which could be used to rank species for leaf and stem proportions in the sward. [source] | |||||||||||||||||||||||||