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- Biurrun, Idoia, et al.
(författare)
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Benchmarking plant diversity of Palaearctic grasslands and other open habitats
- 2021
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Ingår i: Journal of Vegetation Science. - Oxford : John Wiley & Sons. - 1100-9233 .- 1654-1103. ; 32:4
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Tidskriftsartikel (refereegranskat)abstract
- Journal of Vegetation Science published by John Wiley & Sons Ltd on behalf of International Association for Vegetation Science.Aims: Understanding fine-grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine-grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups). Location: Palaearctic biogeographic realm. Methods: We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m2 and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class. Results: Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi-natural) grasslands and natural grasslands are the richest vegetation type. The open-access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats. Conclusions: The GrassPlot Diversity Benchmarks provide high-quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation-plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology. © 2021 The Authors.
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- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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- Kirnbauer, A., et al.
(författare)
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Mechanical properties and thermal stability of reactively sputtered multi-principal-metal Hf-Ta-Ti-V-Zr nitrides
- 2020
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Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 389
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Tidskriftsartikel (refereegranskat)abstract
- Crystalline (Hf,Ta,Ti,V,Zr)N nitride thin films, with a high-entropy metal-sublattice, were synthesized at 440 degrees C by reactive magnetron sputtering using an equimolar Hf-Ta-Ti-V-Zr-compound target. The coatings are single-phase fcc structured mono-nitrides for N-2/(Ar + N-2) flow-rate-ratios (f(N2)) between 30 and 45%. For higher f(N2) a small fraction of a second phase (next to the fcc matrix) can be detected by X-ray diffraction (XRD) and selected area electron diffraction (SAED). All coatings studied (prepared with f(N2) between 30 and 60%) show similar chemical compositions and hardness (H) values between 30.0 and 34.0 GPa with indentation moduli of similar to 460 GPa. Atom probe tomography (APT) indicates a homogenous distribution of all elements within our fcc-(Hf,Ta,Ti,V,Zr)N even after vacuum-annealing at 1300 degrees C. While H decreased from 32.5 to 28.1 GPa by this annealing treatment, the coating is still single-phase fcc structured with a defect density (expressed by XRD and SAED features, transmission electron microscopy contrast, and grain sizes) comparable to the as-deposited state. Only after vacuum-annealing at 1500 degrees C, XRD and APT reveal the formation of hexagonal structured (Ta,V)(2)N. The onset of nitrogen-loss - detected by thermogravimetric analysis - is similar to 1350 degrees C. Based on our results we can conclude that the sluggish diffusion within our fcc-(Hf,Ta,Ti,V,Zr)N warrants the single-phase fcc structure up to 1300 degrees C, although ab initio based calculations would suggest the lower-entropy products [fcc-(Hf,Zr)N, fcc-(Ta,V)N, and fcc-TiN] and [fcc-(Hf,Zr)N and fcc-(Ta,Ti,V)N] to be energetically more stable up to 1302 K.
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