scholarly journals The Ecological Interpretation of Unbiased Estimator for the Taxonomic Ratio: Different Approaches for Local and Regional Flora

2021 ◽  
Vol 40 (4) ◽  
pp. 348-356
Author(s):  
Olexander Zhukov ◽  
Ludmila Arabadzhy-Tipenko
Keyword(s):  
Linear Equation ◽  
Unbiased Estimator ◽  
Competitive Exclusion ◽  
Morphological Features ◽  
Ecological Context ◽  
Taxonomic Relationship ◽  
Taxonomic Relation ◽  
Wide Range ◽  
Species Area ◽  
Species Area Relationship

Abstract Taxonomic ratio in an ecological context is considered as an indicator of the level of competitive exclusion. In spite of more than a century of discussions on taxonomic ratio, the problem of finding an unbiased estimator for flora characterisation remains unsolved. The traditional form of taxonomic ratio (species/genus or species/families ratio) is biased, which depends on the area of territory for which the floral composition was established. This circumstance makes the taxonomic ratio an inadequate characteristic of the flora. To solve the problem of finding an unbiased estimator for the taxonomic ratio, we have combined two fundamental ecological generalisations. The first is that species that belong to the same genus usually live in similar habitats and have similar morphological features. The struggle for life between species from the same genus is, therefore, more intense than between species from different genera. The second is species–area relationship. We have considered the problem of finding an unbiased taxonomic relationship using the Arrhenius curves to fit species–area relationships. This combination allowed us to find a form of unbiased taxonomic relationship. The example of Cyanophyceae flora shows that this indicator is closely related to a wide range of ecological and biogeographical characteristics of vegetation. The residual of the linear equation of dependence of the logarithm of the number of species on the logarithm of the number of genera is an unbiased indicator of the taxonomic relation, which is independent of the number of genera (or number of families) and the sampling size (or area). An unbiased taxonomic relationship is a characteristic of regional flora, which depends on a wide range of its ecological and biogeographical features.

scholarly journals Fine-grain beta diversity in Palaearctic open vegetation: variability within and between biomes and vegetation types

2021 ◽  
Vol 2 ◽  
pp. 293-304
Author(s):  
Iwona Dembicz ◽  
Jürgen Dengler ◽  
François Gillet ◽  
Thomas J. Matthews ◽  
Manuel J. Steinbauer ◽  
...  
Keyword(s):  
Beta Diversity ◽  
Vascular Plants ◽  
Explanatory Power ◽  
Species Group ◽  
Vegetation Types ◽  
Fine Grain ◽  
Natural Grasslands ◽  
Wide Range ◽  
Species Area ◽  
Species Area Relationship

Aims: To quantify how fine-grain (within-plot) beta diversity differs among biomes and vegetation types. Study area: Palaearctic biogeographic realm. Methods: We extracted 4,654 nested-plot series with at least four different grain sizes between 0.0001 m² and 1,024 m² from the GrassPlot database spanning broad geographic and ecological gradients. Next, we calculated the slope parameter (z-value) of the power-law species–area relationship (SAR) to use as a measure of multiplicative beta diversity. We did this separately for vascular plants, bryophytes and lichens and for the three groups combined (complete vegetation). We then tested whether z-values differed between biomes, ecological-physiognomic vegetation types at coarse and fine levels and phytosociological classes. Results: We found that z-values varied significantly among biomes and vegetation types. The explanatory power of area for species richness was highest for vascular plants, followed by complete vegetation, bryophytes and lichens. Within each species group, the explained variance increased with typological resolution. In vascular plants, adjusted R2 was 0.14 for biomes, but reached 0.50 for phytosociological classes. Among the biomes, mean z-values were particularly high in the Subtropics with winter rain (Mediterranean biome) and the Dry tropics and subtropics. Natural grasslands had higher z-values than secondary grasslands. Alpine and Mediterranean vegetation types had particularly high z-values whereas managed grasslands with benign soil and climate conditions and saline communities were characterised by particularly low z-values. Conclusions: In this study relating fine-grain beta diversity to typological units, we found distinct patterns. As we explain in a conceptual figure, these can be related to ultimate drivers, such as productivity, stress and disturbance, which can influence z-values via multiple pathways. The provided means, medians and quantiles of z-values for a wide range of typological entities provide benchmarks for local to continental studies, while calling for additional data from under-represented units. Syntaxonomic references: Mucina et al. (2016) for classes occurring in Europe; Ermakov (2012) for classes restricted to Asia. Abbreviations: ANOVA = analysis of variance; EDGG = Eurasian Dry Grassland Group; SAR = species-area relationship.

Spatial Scale and Species Diversity: Building Species–Area Curves from Species Incidence

2005 ◽  
Author(s):  
Jack J. Lennon ◽  
William Edward Kunin
Keyword(s):  
Species Diversity ◽  
Absolute Number ◽  
Simple Graph ◽  
Number Of Species ◽  
Wide Range ◽  
Species Incidence ◽  
Species Area ◽  
Species Area Relationship ◽  
The Relationship ◽  
Reductionist Approach

This chapter is largely focused on the species–area relationship (SAR), although it may not seem so for much of the time. Bear with us; we will get there in the end. Our aim is to provide insights into how the relationship works, and how it is built. This leads us to take a rather reductionist approach, and to break down the SAR into its component parts. We will spend a substantial section of this chapter examining these pieces and their properties. We will then explore the logic by which the parts are reassembled, and will explore how biological and biogeographical properties of a system may affect the SAR. Before attempting this feat, however, we should begin with a brief discussion of the SAR itself, to explain why it is worth making such a fuss over. The SAR is, after all, only a simple graph: a plot of the number of species found in a sample as a function of the area sampled. Ecologists being an argumentative lot, we cannot even all agree on what this plot should look like; Gleason (1922, see also Williams 1964) argued that the absolute number of species should be plotted as a function of the logarithm of area, whereas Arrhenius (1921, see also Preston 1960) suggested that both species and area should be plotted logarithmically. Connor and McCoy (1979) found cases that fit both models, and two others besides (log species by untransformed area, and neither variable transformed). However it’s plotted, the SAR is not even a particularly attractive or elegant graph—at its best (!) it is simply a straight diagonal line within a tight scatter of datapoints on a rectangular plot. Hardly something to set the pulse racing. Yet the SAR is exciting stuff; that simple line encapsulates a great deal of information about the diversity of biological systems across a wide range of scales.

scholarly journals Fine-grain beta diversity in Palaearctic open vegetation: variability within and between biomes and vegetation types

2021 ◽  
Vol 2 ◽  
pp. 293-304
Author(s):  
Iwona Dembicz ◽  
Jürgen Dengler ◽  
François Gillet ◽  
Thomas J. Matthews ◽  
Manuel J. Steinbauer ◽  
...  
Keyword(s):  
Beta Diversity ◽  
Vascular Plants ◽  
Explanatory Power ◽  
Species Group ◽  
Vegetation Types ◽  
Fine Grain ◽  
Natural Grasslands ◽  
Wide Range ◽  
Species Area ◽  
Species Area Relationship

Aims: To quantify how fine-grain (within-plot) beta diversity differs among biomes and vegetation types. Study area: Palaearctic biogeographic realm. Methods: We extracted 4,654 nested-plot series with at least four different grain sizes between 0.0001 m² and 1,024 m² from the GrassPlot database spanning broad geographic and ecological gradients. Next, we calculated the slope parameter (z-value) of the power-law species–area relationship (SAR) to use as a measure of multiplicative beta diversity. We did this separately for vascular plants, bryophytes and lichens and for the three groups combined (complete vegetation). We then tested whether z-values differed between biomes, ecological-physiognomic vegetation types at coarse and fine levels and phytosociological classes. Results: We found that z-values varied significantly among biomes and vegetation types. The explanatory power of area for species richness was highest for vascular plants, followed by complete vegetation, bryophytes and lichens. Within each species group, the explained variance increased with typological resolution. In vascular plants, adjusted R2 was 0.14 for biomes, but reached 0.50 for phytosociological classes. Among the biomes, mean z-values were particularly high in the Subtropics with winter rain (Mediterranean biome) and the Dry tropics and subtropics. Natural grasslands had higher z-values than secondary grasslands. Alpine and Mediterranean vegetation types had particularly high z-values whereas managed grasslands with benign soil and climate conditions and saline communities were characterised by particularly low z-values. Conclusions: In this study relating fine-grain beta diversity to typological units, we found distinct patterns. As we explain in a conceptual figure, these can be related to ultimate drivers, such as productivity, stress and disturbance, which can influence z-values via multiple pathways. The provided means, medians and quantiles of z-values for a wide range of typological entities provide benchmarks for local to continental studies, while calling for additional data from under-represented units. Syntaxonomic references: Mucina et al. (2016) for classes occurring in Europe; Ermakov (2012) for classes restricted to Asia. Abbreviations: ANOVA = analysis of variance; EDGG = Eurasian Dry Grassland Group; SAR = species-area relationship.

scholarly journals The species–area relationship and evolution

2006 ◽  
Vol 241 (3) ◽  
pp. 590-600 ◽  
Author(s):  
Daniel Lawson ◽  
Henrik Jeldtoft Jensen
Keyword(s):  
Species Area ◽  
Species Area Relationship

scholarly journals Adaptation limits ecological diversification and promotes ecological tinkering during the competition for substitutable resources

2018 ◽  
Vol 115 (44) ◽  
pp. E10407-E10416 ◽  
Author(s):  
Benjamin H. Good ◽  
Stephen Martis ◽  
Oskar Hallatschek
Keyword(s):  
Evolutionary Dynamics ◽  
Competitive Exclusion ◽  
Directional Selection ◽  
Ecological Niches ◽  
Ecological Diversification ◽  
Effective Competition ◽  
Uptake Rates ◽  
Wide Range ◽  
Dynamical Features ◽  
Adaptation Limits

Microbial communities can evade competitive exclusion by diversifying into distinct ecological niches. This spontaneous diversification often occurs amid a backdrop of directional selection on other microbial traits, where competitive exclusion would normally apply. Yet despite their empirical relevance, little is known about how diversification and directional selection combine to determine the ecological and evolutionary dynamics within a community. To address this gap, we introduce a simple, empirically motivated model of eco-evolutionary feedback based on the competition for substitutable resources. Individuals acquire heritable mutations that alter resource uptake rates, either by shifting metabolic effort between resources or by increasing the overall growth rate. While these constitutively beneficial mutations are trivially favored to invade, we show that the accumulated fitness differences can dramatically influence the ecological structure and evolutionary dynamics that emerge within the community. Competition between ecological diversification and ongoing fitness evolution leads to a state of diversification–selection balance, in which the number of extant ecotypes can be pinned below the maximum capacity of the ecosystem, while the ecotype frequencies and genealogies are constantly in flux. Interestingly, we find that fitness differences generate emergent selection pressures to shift metabolic effort toward resources with lower effective competition, even in saturated ecosystems. We argue that similar dynamical features should emerge in a wide range of models with a mixture of directional and diversifying selection.

Fragmentation, grazing and the species-area relationship

Ecography ◽  
2012 ◽  
Vol 35 (3) ◽  
pp. 224-231 ◽  
Author(s):  
Tiffany L. Bogich ◽  
Gary M. Barker ◽  
Karin Mahlfeld ◽  
Frank Climo ◽  
Rhys Green ◽  
...  
Keyword(s):  
Species Area ◽  
Species Area Relationship

Self‐Similarity, the Power Law Form of the Species‐Area Relationship, and a Probability Rule: A Reply to Maddux

2004 ◽  
Vol 163 (4) ◽  
pp. 627-633 ◽  
Author(s):  
Annette Ostling ◽  
John Harte ◽  
Jessica L. Green ◽  
Ann P. Kinzig
Keyword(s):  
Power Law ◽  
Self Similarity ◽  
Species Area ◽  
Species Area Relationship

scholarly journals Research Regarding the Morphological Characteristics of Calendula Officinalis Local

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Cristina ZEPA ZEPA CORADINI ◽  
Valeriu TABÄ‚RÄ‚ ◽  
Doru PETANEC ◽  
Lavinia MICU ◽  
Irina PETRESCU ◽  
...  
Keyword(s):  
Local Population ◽  
Economic Value ◽  
Morphological Characteristics ◽  
Morphological Features ◽  
Morphological Aspect ◽  
Calendula Officinalis ◽  
Experimental Field ◽  
Wide Range ◽  
Polymorphic Species ◽  
Flowering Process

Marigolds have an important economic value which let to an increase production and cultivation being thus used in a wide range of fields. One of the basic elements regarding marigolds production is represented by anthodia with flowers and seeds determined by the blossom and the number of anthodium on the plant. The plant’s blossom is determined by the n umber of lingulate flowers from the external side of the anthodium where seeds grow. Calendula is a polymorphic species, forming during its evolution not only flowering, but also semi-flowering anthodia and simple flowers. In the experimental field of UASVM Timisoara we performed a series of research regarding the morphological features of six local population of marigold from the western part of the country. Flowers’ blooming proved to have a different evolution due to the influence manifested by the local population and also by the harvest results. This blooming phenomenon proved to highly influence the production elements. Blooming influence upon anthodia mass of seeds proved to be as similar as in case of anthodia with flowers. At the beginning of the harvest period, the anthodia mass of seeds proved to be maxim. According to the information collected during research, anthodia flowering fails to reestablish during harvest. The flowering process influences the number and the size of the seeds. Moreover, flowers blooming process may lead to the formation of homogenous seeds, not only in size, but also as regards their morphological aspect. The seeds from the flowering anthodia proved to be homogenous in comparison with other anthodia and had even better technological qualities.

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