scholarly journals Individual-level trait diversity predicts phytoplankton community properties better than species richness or evenness

2017 ◽  
Vol 12 (2) ◽  
pp. 356-366 ◽  
Author(s):  
Simone Fontana ◽  
Mridul Kanianthara Thomas ◽  
Mirela Moldoveanu ◽  
Piet Spaak ◽  
Francesco Pomati
Keyword(s):  
Species Richness ◽  
Phytoplankton Community ◽  
Individual Level ◽  
Trait Diversity ◽  
Better Than

Definiteness in written Swedish by Finnish-speaking immersion pupils at the end of immersion

2018 ◽  
Vol 6 (1) ◽  
pp. 57-84
Author(s):  
Eeva-Liisa Nyqvist
Keyword(s):  
Control Group ◽  
Group Level ◽  
Individual Level ◽  
Definite Form ◽  
Spontaneous Writing ◽  
Acquisition Order ◽  
The Individual ◽  
The Right ◽  
Better Than

Abstract There are two primary goals for this study – first, to analyse definiteness and article use in spontaneous writing in Swedish by 15-year-old Finnish immersion students (n = 162) and secondly, to compare their performance with that of non-immersion students at the same age (n = 67). Analyses at the group level show that immersion students usually perform significantly better than the control group, but they also reveal similar problems to what L2-Swedish non-immersion students have demonstrated in previous studies, such as omission of indefinite articles and difficulty in choosing the right definite form of the noun. Still, these inaccuracies occurred less often in the data from the immersion students. The studied constructions also show at the group level an acquisition order similar to that reported in previous studies, explainable by different aspects of complexity and cross-linguistic influence. Analyses on the individual level, however, show different acquisition orders depending on the criteria being used.

The Prediction of Lacustrine Phytoplankton Diversity

1981 ◽  
Vol 38 (5) ◽  
pp. 524-534 ◽  
Author(s):  
Bruce D. LaZerte ◽  
Susan Watson
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Good Predictor ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Taxonomic Composition ◽  
Phytoplankton Community Structure ◽  
Trophic Gradient ◽  
Phytoplankton Diversity ◽  
Total Phytoplankton

We tested the hypothesis that total phytoplankton biomass can predict phytoplankton community structure independent of its taxonomic composition. From a 2-yr study on Lake Memphremagog, Quebec, which exhibits a marked axial trophic gradient, 133 samples were rarefied to uniform count sizes and a range of diversity numbers, based on proportional biomass, was calculated for each. Biomass is a good predictor of evenness (0.7 < R < 0.9), but not species richness (0.1 < R < 0.3), and this prediction is independent of changes in taxonomic composition. Species richness is more directly related to season and changes in taxonomic composition.Key words: diversity, evenness, species richness, phytoplankton

scholarly journals BLOOM OF Gonyaulax spinifera (DINOPHYCEAE: GONYAULACALES) IN ENSENADA DE LA PAZ LAGOON, GULF OF CALIFORNIA

2014 ◽  
Vol 29 (1) ◽  
pp. 11
Author(s):  
I. Gárate -Lizárraga ◽  
Ma. S. Muñetón -Gómez ◽  
B. Pérez -Cruz ◽  
J. A. Díaz -Ortíz
Keyword(s):  
Species Richness ◽  
Gulf Of California ◽  
Phytoplankton Community ◽  
Seawater Temperature ◽  
Low Frequency ◽  
Wind Forcing ◽  
La Paz ◽  
Tidal Water ◽  
High Species Richness ◽  
Water Accumulation

During a sampling on 24 September 2012 in the coastal lagoon, Ensenada de La Paz, a small bloom of the dinoflagellate Gonyaulax spinifera was detected. Its abundance varied from 401 to 1342 × 103 cells L–1. Cells of G. spinifera ranged from 34 to 50 μm in length and 22 to 35 μm in width (n = 30). Seawater temperature and salinity were 29 °C and 35.5, respectively. The species composition of the bloom was recorded. The phytoplankton community had high species richness, resulting from a mix of benthic and pelagic diatoms and dinoflagellates, as well as cyanobacteria that occurred with low frequency. This brief proliferation lasted around three hours and may have been caused by tidal water accumulation along the shore. Although G. spinifera is a producer of yessotoxin, no fish or invertebrates were apparently killed by this bloom, which was rapidly dispersed by tides and wind-forcing. Florecimiento de Gonyaulax spinifera (Dinophyceae: Gonyaulacales) en la laguna Ensenada de La Paz, Golfo de California Durante un muestreo el 24 de septiembre de 2012 en la laguna costera Ensenada de La Paz se detectó un pequeño florecimiento del dinoflagelado Gonyaulax spinifera. Los valores de abundancia variaron de 401 a 1342 × 103 céls L–1. Los especímenes de G. spinifera presentaron un intervalo de tallas de 34 a 50 μm de longitud y de 22 a 35μm de ancho (n = 30). La temperatura del agua fue de 20 °C y la salinidad fue de 35.5. Se determinó la composición de especies durante este florecimiento. Como resultado de la mezcla de especies bentónicas y pelágicas de diatomeas y dinoflagelados, así como de algunas cianobacterias poco frecuentes, la comunidad del fitoplancton presentó una riqueza de especies alta. Esta pequeña proliferación se observó por alrededor de 3 horas y pudo ser ocasionada por la marea acumulándola en la línea de costa. Aunque G. spinifera es una especie productora de yessotoxinas, no se observaron peces ni invertebrados muertos durante este florecimiento, el cual se dispersó rápidamente por efecto de la marea y la fuerza del viento.

Diversity components and assembly patterns of plant functional traits determine community spatial stability under resource gradients in a desert steppe

2016 ◽  
Vol 38 (5) ◽  
pp. 511 ◽  
Author(s):  
Zhao Na ◽  
Wang Zhengwen ◽  
Shao Xinqing ◽  
Wang Kun
Keyword(s):  
Species Richness ◽  
Functional Traits ◽  
Nutrient Availability ◽  
Functional Group ◽  
Group Composition ◽  
Functional Trait ◽  
Spatial Stability ◽  
Trait Diversity ◽  
The Relationship ◽  
Functional Trait Diversity

The diversity–stability relationship has been addressed and debated for decades, but how this relationship is affected by nutrient availability remains contentious. In the present study we assessed the effects of plant diversity, in terms of species richness, functional group composition and functional trait diversity, on the spatial stability of net primary productivity (NPP) following nitrogen and phosphorus application. In addition, we explored how functional traits at the species level contribute to the spatial stability of NPP. The results support the hypothesis that greater diversity leads to higher spatial stability. This relationship was highly dependent on soil nutrient availability, and increasing species richness or functional trait diversity significantly increased spatial variation of NPP under a high N fertilisation level. The effects of high mineral fertilisation rates may perhaps have masked the effects of plant diversity. Although species richness or functional trait diversity of the original and modified communities from which species with particular functional traits had been removed were significantly different, there were no differences in the coefficients of variation in the NPP of those communities. The lack of difference demonstrated that the relationship between spatial variability and biodiversity depended on the measure of diversity applied and that the functional group composition exerted a stronger effect than other diversity measures. Further analyses revealed that spatial stability of NPP was enhanced with increased diversity in vegetative plant height, rooting depth and the presence of legume, and diminished with diversity in the root system type and life cycle under some fertilisation treatments. The present study demonstrates that the relationship between biodiversity and ecosystem functioning is variable with different diversity, identity and environmental factors. Evaluating the contribution of particular traits to community stability will ultimately help us better understand the mechanisms underlying the diversity–stability relationship.

Macrofungal diversity of a temperate oak forest: a test of species richness estimators

1999 ◽  
Vol 77 (7) ◽  
pp. 1014-1027 ◽  
Author(s):  
John Paul Schmit ◽  
John F Murphy ◽  
Gregory M Mueller
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Deciduous Forest ◽  
Hardwood Forests ◽  
Oak Forest ◽  
Species Richness Estimation ◽  
Indiana Dunes ◽  
Richness Estimators ◽  
Diversity Estimates ◽  
Better Than

Two 0.1-ha plots, each divided into 10 contiguous subplots, were established in a Quercus-dominated deciduous forest in the Indiana Dunes National Lakeshore. Macrofungi were surveyed on these plots at weekly intervals during the fruiting season over 3 years. During this survey 177 species were recorded, including 30 species inhabiting leaf litter, 36 ectomycorrhizal species, 29 non-mycorrhizal soil-inhabiting species, and 79 wood-inhabiting species. This species richness is comparable to, but slightly higher than, that reported by other plot-based studies undertaken in hardwood forests. We compared the ability of seven species-richness estimation techniques to determine the true species richness on these plots. While some estimators performed better than others, in general the estimations were too low based on the following year's data and were not consistent from year to year. We found some evidence of spatial autocorrelation of communities of fungi found in adjacent subplots. This indicates that the benefit of using contiguous subplots to increase the homogeneity of the area sampled needs to be balanced against the possibility of underestimating the species richness of an area because of spatial autocorrelation.Key words: macrofungi, species diversity, diversity estimates, Indiana Dunes.

scholarly journals Reversal in the relationship between species richness and turnover in a phytoplankton community

Ecology ◽  
2012 ◽  
Vol 93 (11) ◽  
pp. 2435-2447 ◽  
Author(s):  
Blake Matthews ◽  
Francesco Pomati
Keyword(s):  
Species Richness ◽  
Phytoplankton Community ◽  
The Relationship

scholarly journals Do Financial Professionals Process Information Better as a Group Than Non-Professionals?

2021 ◽  
Vol 14 (5) ◽  
pp. 230
Author(s):  
Orie E. Barron ◽  
Charles R. Enis ◽  
Hong Qu
Keyword(s):  
Information Processing ◽  
Group Level ◽  
Process Information ◽  
Forecast Performance ◽  
Individual Level ◽  
Level Versus ◽  
The Difference ◽  
Highly Correlated ◽  
The Individual ◽  
Better Than

In this study, we study information processing by financial professionals benchmarked with non-professionals and how correlation among individual forecasts explains the group level forecast performance. In an experiment in which participants make price forecasts based on common financial information, we find that individual professionals are no better than individual non-professionals in forecasting, but professionals’ mean forecasts are superior. Our analysis suggests that financial professionals’ individual errors are less correlated as they process information from more diverse perspectives. This leads to superior mean forecasts because the uncorrelated individual errors cancel each other out in the aggregate. In contrast, non-professionals are similar in using salient information such as earnings or cash flow. As a result, their individual errors are highly correlated. Instead of cancelling each other out, the individual errors are enlarged in the aggregated mean forecasts. We are the first to show the difference in the comparisons of professionals and non-professionals at the group level versus at the individual level. Our paper contributes to the literature by documenting the evidence of diversity in information processing by financial professionals.

Knowledge of the firm, combinative capabilities, and the replication of technology

2009 ◽  
Author(s):  
Bruce Kogut ◽  
Udo Zander
Keyword(s):  
Social Community ◽  
Individual Level ◽  
Dynamic View ◽  
The Social ◽  
The Future ◽  
Dynamic Perspective ◽  
Cumulative Knowledge ◽  
Prevailing View ◽  
Organizing Principles ◽  
Better Than

- How should we understand why firms exist? A prevailing view has been that they serve to keep in check the transaction costs arising from the self-interested motivations of individuals. We develop in this article the argument that whal firms do better than markets is the sharing and transfer of the knowledge of individtials and groups within an organization. This knowledge consists of information (e.g., who knows what) and of know-how (e.g., how to organize a research team). What is central to our argument is that knowledge is held by individuals, but is also expressed in regularities by which members cooperate in a social community (i.e.. group, organization, or network). If knowledge is only held at Ihe individual level, then firms could change simply by employee turnover. Because we know that hiring new workers is not equivalent to changing the skills of a firm, an analysis of what firms can do must understand knowledge as embedded in the organizing principles by which people cooperate within organizations. Based on this discussion, a paradox is identified: efforts by a firm to grow by the replication of its technology enhances the potential for imitation. By considering how firms can deter imitation by innovation, we develop a more dynamic view of how firms create new knowledge. We build up this dynamic perspective by suggesting that firms learn new skills by recombining their curreni capabilities. Because new ways of cooperating cannot be easily acquired, growth occurs by building on the social relationships that currently exist in a firm. What a firm has done before tends to predict what it can do in the future. In this sense, the cumulative knowledge of the firm provides options to expand in new but uncertain markets in the future. We discuss at length the example of the make/buy decision and propose several testable hypotheses regarding the boundaries of the firm, without appealing to the notion of opportunism.

scholarly journals Estimating Diversity Through Time Using Molecular Phylogenies: Old and Species-Poor Frog Families are the Remnants of a Diverse Past

2019 ◽  
Author(s):  
O Billaud ◽  
D S Moen ◽  
T L Parsons ◽  
H Morlon
Keyword(s):  
Species Richness ◽  
Probabilistic Approach ◽  
R Package ◽  
Extinction Rate ◽  
Competitive Effects ◽  
Phenotypic Divergence ◽  
Poor Group ◽  
Diversity Dynamics ◽  
Diversity Estimates ◽  
Better Than

Abstract Estimating how the number of species in a given group varied in the deep past is of key interest to evolutionary biologists. However, current phylogenetic approaches for obtaining such estimates have limitations, such as providing unrealistic diversity estimates at the origin of the group. Here, we develop a robust probabilistic approach for estimating diversity through time curves and uncertainty around these estimates from phylogenetic data. We show with simulations that under various realistic scenarios of diversification, this approach performs better than previously proposed approaches. We also characterize the effect of tree size and undersampling on the performance of the approach. We apply our method to understand patterns of species diversity in anurans (frogs and toads). We find that Archaeobatrachia—a species-poor group of old frog clades often found in temperate regions—formerly had much higher diversity and net diversification rate, but the group declined in diversity as younger, nested clades diversified. This diversity decline seems to be linked to a decline in speciation rate rather than an increase in extinction rate. Our approach, implemented in the R package RPANDA, should be useful for evolutionary biologists interested in understanding how past diversity dynamics have shaped present-day diversity. It could also be useful in other contexts, such as for analyzing clade–clade competitive effects or the effect of species richness on phenotypic divergence.

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