170,074 research outputs found
Ramet demography in a ring-forming clonal sedge
No full text1 In a calcareous dry grassland community in central Europe genets of the clonal sedge Carex humilis form very distinct rings of densely aggregated ramets. As genet growth form is generated by ramet population dynamics, ramet demography must be studied in order to understand how rings develop. We analysed how ramet demography in C. humilis depends on ramet position within the ring and how this is linked to ramet size. 2 The per ramet population growth rate was > 1 at the periphery of rings but < 1 in the interior, meaning that the population increases at the periphery but decreases in the interior. The population growth rate differed mainly because ramets were smaller in the interior and because smaller ramets produced fewer vegetative ramets. It is unlikely that the smaller ramet size is caused by negative density dependence, interspecific competition, internal control or resource depletion. 3 The study covered four growing seasons and we found considerable variation in ramet demography between years. The net result for the 4 years was that the total number of C. humilis ramets in the population increased. However, both production of vegetative ramets and ramet size decreased during the study period and if this trend continues population size will instead decrease
Ramet production for male and female genotypes
No full textRamet production for male and female genotype
Carex humilis - a caespitose clonal plant: ramet demography, ring formation, and community interactions
No full textCarex humilis forms rings of densely aggregated ramets in dry grassland vegetation in Central Europe. In the thesis I conclude that ramet demography is important both for analyzing fitness in clonal plants and for understanding how C. humilis rings are formed. I studied the ramet demography of C. humilis from 1993-1998 at the Hexenberg mountain, 300 m.a.s., 60 km east of Vienna, Austria. In total, the size of the ramet population increased during the study period but there was considerable variation in ramet population growth rate between years. Flowering ramets of C. humilis did not produce any offspring ramets, and at the study location, the seeds were either infected by smut of infested by insect larvae. The size of vegetative parent ramets positively correlated to both number and size of offspring ramets, i.e. larger parent ramets produced both more and larger offspring ramets. The ramet population growth rate was higher in the periphery of rings than in the interior, mainly due to the ramets being larger in the periphery. Because of this, of the ramet population size in the periphery of rings increased, whereas the ramet population size in the interior decreased. However, the ramet density in the interior was lower than would be predicted from the population growth rate alone, and I conclude that the difference is due to the centrifugal dispersal of ramets. A simulation model showed that ramet populations with lower maximum population growth rate, or with more peripheral dispersal, formed rings, whereas populations with higher maximum growth rates or less peripheral dispersal formed filled circles. A size structured matrix model showed that although there was variance in the production of all size classes, both between years as well as between periphery and interior, it was only the variance in the production of larger ramets that was important for the variance in the asymptotic population growth rate. Compared to the surrounding vegetation, the cover of most other plants was reduced inside C. humilis rings. In addition, the soil under C. humilis rings contained more moisture, nitrogen and phosphorus than the surrounding soil. Hence, the reason behind the lower population growth rate in the interior of rings was neither competition from other plants, nor depletion of any of the soil resources measured
Ramet dynamics in a centrifugally expanding clonal sedge: a matrix analysis
No full textCarex humilis is a clonal sedge that can form distinct rings of densely aggregated ramets. We hypothesize that rings form because both production of new ramets and ramet dispersal are positively correlated to ramet size. This would lead to an overrepresentation of fast-moving and large ramets with high ramet production at the periphery, whereas slow-moving and small ramets with low ramet production would mainly be found in the interior of rings. We use matrix models to analyse how ramet populations both at the periphery and in the interior develop in the absence of ramet dispersal. We found that the stable size class distributions of ramets predicted by the models were not different from the distributions found in the field. Also, the asymptotic ramet population growth rates (lambda(1)) were the same. Hence, we conclude that rings would form even in the absence of a link between ramet dispersal and ramet production. Further analysis of the matrix models showed that the ramet population increases at the periphery but decreases in the interior of rings because medium and large ramets produce fewer large ramets in the interior than at the periphery. We also found that the temporal variance in lambda(1) and transitions rates during the four study years was much higher at the periphery than in the interior. Our results suggest that rings may form because C. humilis ramets use below-ground resources from a much larger area than the one covered by the shoots. As the clone grows larger, the soil volume available to the ramets in the interior decreases because their access to soil outside the ring is cut-off by the ramets at the periphery. Ramet density in the interior is therefore decreasing
Deciphering the Ramet System of a Bamboo Plant in Response to Intensive Management
No full textIntensive management is a common practice in bamboo plantations to ensure higher shoot yields. However, the effects of these management practices on ramet systems are understudied. A pot experiment was conducted to explore the process of propagation for potted bamboo seedlings (Phyllostachys praecox C. D. Chu et C. S. Chao “Prevernalis”) from a single mother bamboo to a ramet system exposed to a chronosequence of intensively managed bamboo forest soils. The ramet system of potted bamboo seedlings reached seven branching grades after two growth cycles. During ramet system expansion, the rhizome length and rhizome internodes decreased with increasing branching grade and the extension of intensive management periods. In the bud bank for each branching grade, the front branching grade was dominated by the bud output, which was conducive to consolidating the occupied living space. The back branching grade was dominated by bud input to continue rhizome penetration. With increasing branching, the mulching soil significantly inhibited rhizome bud germination and dormant bud accumulation. The mulching soil was not conducive to branch expansion in the ramet system, and ramet system expansion was predominantly based on the branching of the rhizome modules. With increasing branching and the extension of intensive management periods, rhizome branches decreased markedly. Our findings indicate that bamboo mulching inhibits branching and causes a differential reaction in branching types. The long-term mulching of bamboo forest soil was not conducive to the healthy and sustainable growth of bamboo. These results provide a basis for further research on the relationship between the bamboo ramet system and its productivity, as well as the population construction and maintenance mechanisms of bamboo ramet systems in the field
GIS shape files of male and female ramet location data
No full textGIS shape files containing male and female ramet location data used to analyze mechanisms underlying sex ratio variation
Summary of Ramet v. State, 125 Nev. Adv. Op. No. 19
No full textAppellant Daniel Anthony Ramet was convicted of first-degree murder. On appeal, Ramet contended that the testimony concerning his refusal to consent to a search of his home, taken together with the prosecutor’s comment on it, was violative of his Fourth Amendment rights. The Court concluded that the district court erred in allowing testimony and argument regarding Ramet’s invocation of his Fourth Amendment right. However, they further concluded that the error in admitting the statements was harmless. The Court therefore affirmed Ramet’s conviction.Ó
Jean Bodin and religious toleration
No full textIn the wake of the Protestant Reformation and the division of Western Christianity into rival religious camps, France descended into religious civil war in the years 1562-1598. The question then was how to respond to it. Writing after Spinoza’s championing of freedom of religious thought but before Hobbes’ advocacy of a strong sovereign who would dictate the prayers and forms of religious worship for the nation as a method of avoiding religious conflict, Bodin argued for religious toleration, indeed for a degree of religious toleration that was radical in its daypublishedVersionCopyright (c) 2019 Sabrina P. Ramet. This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License
Data from: The spatial ecology of sex ratios in a dioecious plant: relations between ramet and genet sex ratios
No full text1. In clonal dioecious plants, the frequency and spatial distribution of flowering ramets contains information on the underlying genet sex ratio. These measures can also provide insight on potential ecological mechanisms causing variation and bias in sex ratios among populations.
2. We used a novel likelihood-based approach and spatial clustering model to estimate the genet sex ratios from flowering ramet data collected from 32 populations of dioecious Thalictrum pubescens, a clonal species from eastern N. America that occupies moist wetland and forested environments. We investigated sex ratios of seed families, clone size, patterns of flowering and plant height to determine potential causes of sex ratio bias.
3. Flowering ramet sex ratios varied considerably among populations but were significantly male-biased. Seed families grown to flowering also exhibited the same degree of male bias. Both models predicted close correspondence between ramet and genet sex ratios. The likelihood model revealed that gender differences in ramet production could not account for biased sex ratios. The spatial clustering model indicated that ramets were significantly clustered at two spatial scales and estimated similar cluster sizes and densities for both sexes. There was no evidence for spatial segregation of the sexes. Both sexes were equally likely to flower in consecutive years and repeated bouts of flowering had no effect on ramet height.
4. Synthesis. Our analyses suggest that the widespread occurrence of male-biased sex ratios in T. pubescens is unlikely to result from sexual differences in clonal growth or habitat preferences. The bias appears to become established early in the life cycle, perhaps at the seed stage as consequence of local resource competition
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