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 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 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 Status of Phenological Research Using Sentinel-2 Data: A Review

2020 ◽  
Vol 12 (17) ◽  
pp. 2760
Author(s):  
Gourav Misra ◽  
Fiona Cawkwell ◽  
Astrid Wingler
Keyword(s):  
Vegetation Index ◽  
Temporal Frequency ◽  
Short Wave ◽  
Current State ◽  
Red Edge ◽  
Natural Grasslands ◽  
Wide Range ◽  
Normalised Difference Vegetation Index ◽  
Satellite Sensors ◽  
Sentinel 2

Remote sensing of plant phenology as an indicator of climate change and for mapping land cover has received significant scientific interest in the past two decades. The advancing of spring events, the lengthening of the growing season, the shifting of tree lines, the decreasing sensitivity to warming and the uniformity of spring across elevations are a few of the important indicators of trends in phenology. The Sentinel-2 satellite sensors launched in June 2015 (A) and March 2017 (B), with their high temporal frequency and spatial resolution for improved land mapping missions, have contributed significantly to knowledge on vegetation over the last three years. However, despite the additional red-edge and short wave infra-red (SWIR) bands available on the Sentinel-2 multispectral instruments, with improved vegetation species detection capabilities, there has been very little research on their efficacy to track vegetation cover and its phenology. For example, out of approximately every four papers that analyse normalised difference vegetation index (NDVI) or enhanced vegetation index (EVI) derived from Sentinel-2 imagery, only one mentions either SWIR or the red-edge bands. Despite the short duration that the Sentinel-2 platforms have been operational, they have proved their potential in a wide range of phenological studies of crops, forests, natural grasslands, and other vegetated areas, and in particular through fusion of the data with those from other sensors, e.g., Sentinel-1, Landsat and MODIS. This review paper discusses the current state of vegetation phenology studies based on the first five years of Sentinel-2, their advantages, limitations, and the scope for future developments.

The Possibility of Manufacturing Long-Length Metal Products with Ultra-Fine Grain Structure by Combination of Strain Effects

2016 ◽  
Vol 685 ◽  
pp. 487-491 ◽  
Author(s):  
Mikhail Chukin ◽  
Marina Polyakova ◽  
Alexandr Gulin ◽  
Olga Nikitenko
Keyword(s):  
Steel Wire ◽  
Continuous Method ◽  
Grain Structure ◽  
Strain Effect ◽  
Strain Effects ◽  
Fine Grain ◽  
Wide Range ◽  
Processing Modes ◽  
Efficiency Estimation ◽  
Metal Products

It is shown that combination of strain effects leads to possessing the ultra-fine grain structure in carbon wire. The continuous method of wire deformation nanostructuring was developed on the basis of simultaneous applying of tension deformation by drawing, bending deformation when going through the system of rolls and torsional deformation on a continuously moving wire. One of the main advantages of the developed method is that various hardware devices and tools already applied for steel wire production can be used to implement this method thus simplifying its introduction to the current industrial equipment. The efficiency estimation of the developed continuous method of deformation nanostructuring was carried out using carbon wire with different carbon content. It is shown that the mechanical properties of the wire after combination of different kinds of strain can vary over a wide range. This method makes it possible to choose such modes of strain effect, which can provide the necessary combination of strength and ductile properties of carbon wire depending on its further processing modes and application.

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

Revision of Pycnandra subgenus Achradotypus (Sapotaceae), with five new species from New Caledonia

2010 ◽  
Vol 23 (3) ◽  
pp. 185 ◽  
Author(s):  
Ulf Swenson ◽  
Jérôme Munzinger
Keyword(s):  
New Caledonia ◽  
Iucn Red List ◽  
Red List ◽  
Corolla Lobe ◽  
Vegetation Types ◽  
New Members ◽  
Infrageneric Classification ◽  
Humid Forest ◽  
Leaf Venation ◽  
Wide Range

Pycnandra is a genus of Sapotaceae (Chrysophylloideae), restricted to New Caledonia, and includes ~60 species. The genus is a member of the monophyletic Niemeyera complex of Australia and New Caledonia and it is characterised by the lack of staminodes and a fruit containing a single seed, plano-convex cotyledons and absence of endosperm. In New Caledonia, several segregate genera have been recognised, but weak cladistic support for these groups and homoplasious morphology renders a narrow generic concept untenable. Instead, a broad generic circumscription of Pycnandra with an infrageneric classification recognising the subgenera Achradotypus, Leptostylis, Pycnandra, Sebertia and Trouettia results in a stable nomenclature. Here we revise Pycnandra subg. Achradotypus that includes 14 species, of which five (P. belepensis, P. blaffartii, P. bracteolata, P. glabella, and P. ouaiemensis) are described as new. Members of subg. Achradotypus are distinguished from other subgenera on the basis of a character combination of two stamens opposite each corolla lobe (except P. litseiflora), glabrous leaves (except P. belepensis and P. decandra), a distinctive reticulate tertiary leaf venation (except P. comptonii), and sepal-like bracts that often are borne along the pedicel. All species are restricted to Grande Terre except for P. decandra, whose distribution also extends to nearby Art Island (Belep Islands), and P. belepensis, which is endemic to that same island. The members grow in a wide range of vegetation types from dry maquis to humid forest, from sea level to the highest mountain massif, and on ultramafic soils to schist and greywacke (not limestone). Because of past and present threats such as mining, logging and fire, preliminary IUCN Red List assessments are provided for all species. Five taxa (P. chartacea, P. decandra subsp. decandra, P. glabella, P. litseiflora, and P. neocaledonica) are proposed the IUCN status Endangered, and P. belepensis and P. ouaiemensis are proposed to be Critically Endangered. We suggest that some locations where these species occur should be given protection in the form of nature reserves.

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
Sign in / Sign up

Export Citation Format

Share Document