51 research outputs found
Context-aware learning of hierarchies of low-fidelity models for multi-fidelity uncertainty quantification
Multi-fidelity Monte Carlo methods leverage low-fidelity and surrogate models
for variance reduction to make tractable uncertainty quantification even when
numerically simulating the physical systems of interest with high-fidelity
models is computationally expensive. This work proposes a context-aware
multi-fidelity Monte Carlo method that optimally balances the costs of training
low-fidelity models with the costs of Monte Carlo sampling. It generalizes the
previously developed context-aware bi-fidelity Monte Carlo method to
hierarchies of multiple models and to more general types of low-fidelity
models. When training low-fidelity models, the proposed approach takes into
account the context in which the learned low-fidelity models will be used,
namely for variance reduction in Monte Carlo estimation, which allows it to
find optimal trade-offs between training and sampling to minimize upper bounds
of the mean-squared errors of the estimators for given computational budgets.
This is in stark contrast to traditional surrogate modeling and model reduction
techniques that construct low-fidelity models with the primary goal of
approximating well the high-fidelity model outputs and typically ignore the
context in which the learned models will be used in upstream tasks. The
proposed context-aware multi-fidelity Monte Carlo method applies to hierarchies
of a wide range of types of low-fidelity models such as sparse-grid and
deep-network models. Numerical experiments with the gyrokinetic simulation code
\textsc{Gene} show speedups of up to two orders of magnitude compared to
standard estimators when quantifying uncertainties in small-scale fluctuations
in confined plasma in fusion reactors. This corresponds to a runtime reduction
from 72 days to about four hours on one node of the Lonestar6 supercomputer at
the Texas Advanced Computing Center.Comment: 25 pages, 12 figures, 3 table
Endemism in the genus Pertusaria (Pertusariales, lichenized Ascomycota) from the Galapagos Islands
This revision of Pertusaria in the Galapagos Islands documents twenty-four species, twenty-two being new to the archipelago. Secondary chemistry correlates well with morphology and anatomy and is particularly useful in distinguishing these taxa. Eight species are described as new to science, and seven are known only from the Galapagos: Pertusaria albineoides, P. cerroazulensis, P. darwiniana, P. medullamarilla, P. stictica, P. thioisidiata and P. xanthoisidiata. Pertusaria lueckingii is new, but it also occurs in Central America (El Salvador). Three new endemic varieties are described based on their chemistry: Pertusaria thioisidiata var. isidiogyrophorica, P. tejocotensis var. stictica and P. xantholeucoides var. thamnolica. In contrast with previous studies on other genera where rates of endemism of 8–10% were observed, in Pertusaria 30–37% of all species and 41–46% of all taxa are considered endemic
What Do the First 597 Global Fungal Red List Assessments Tell Us about the Threat Status of Fungi?
Fungal species are not immune to the threats facing animals and plants and are thus also prone to extinction. Yet, until 2015, fungi were nearly absent on the IUCN Red List. Recent efforts to identify fungal species under threat have significantly increased the number of published fungal assessments. The 597 species of fungi published in the 2022-1 IUCN Red List update (21 July 2022) are the basis for the first global review of the extinction risk of fungi and the threats they face. Nearly 50% of the assessed species are threatened, with 10% NT and 9% DD. For regions with a larger number of assessments (i.e., Europe, North America, and South America), subanalyses are provided. Data for lichenized and nonlichenized fungi are also summarized separately. Habitat loss/degradation followed by climate change, invasive species, and pollution are the primary identified threats. Bias in the data is discussed along with knowledge gaps. Suggested actions to address these gaps are provided along with a discussion of the use of assessments to facilitate on-the-ground conservation efforts. A research agenda for conservation mycology to assist in the assessment process and implementation of effective species/habitat management is presented
What Do the First 597 Global Fungal Red List Assessments Tell Us about the Threat Status of Fungi?
Fungal species are not immune to the threats facing animals and plants and are thus also prone to extinction. Yet, until 2015, fungi were nearly absent on the IUCN Red List. Recent efforts to identify fungal species under threat have significantly increased the number of published fungal assessments. The 597 species of fungi published in the 2022-1 IUCN Red List update (21 July 2022) are the basis for the first global review of the extinction risk of fungi and the threats they face. Nearly 50% of the assessed species are threatened, with 10% NT and 9% DD. For regions with a larger number of assessments (i.e., Europe, North America, and South America), subanalyses are provided. Data for lichenized and nonlichenized fungi are also summarized separately. Habitat loss/degradation followed by climate change, invasive species, and pollution are the primary identified threats. Bias in the data is discussed along with knowledge gaps. Suggested actions to address these gaps are provided along with a discussion of the use of assessments to facilitate on-the-ground conservation efforts. A research agenda for conservation mycology to assist in the assessment process and implementation of effective species/habitat management is presented
Towards a dynamic checklist of lichen-forming, lichenicolous and allied fungi of Ecuador – using the <i>Consortium of Lichen Herbaria</i> to manage fungal biodiversity in a megadiverse country
peer reviewedA checklist of Lichen-forming, Lichenicolous and Allied Fungi of Ecuador is presented with a total of 2599 species, of which 39 are reported for the first time from the country. The names of three species, Hypotrachyna montufariensis, H. subpartita and Sticta hypoglabra, previously not validly published, are validated. Pertusaria oahuensis, originally introduced by Magnusson as ‘ad interim’, is validated as Lepra oahuensis. The form Leucodermia leucomelos f. albociliata is validated. Two new combinations, Fissurina tectigera and F. timida, are made, and Physcia mobergii is introduced as a replacement name for the illegitimate P. lobulata Moberg non (Flörke) Arnold. In an initial step, the checklist was compiled by reviewing literature records of Ecuadorian lichen biota spanning from the late 19th century to the present day. Subsequently, records were added based on vouchers from 56 collections participating in the Consortium of Lichen Herbaria, a Symbiota-based biodiversity platform with particular focus on, but not exclusive to, North and South America. Symbiota provides sophisticated tools to manage biodiversity data, such as occurrence records, a taxonomic thesaurus, and checklists. The thesaurus keeps track of frequently changing names, distinguishing taxa currently accepted from ones considered synonyms. The software also provides tools to create and manage checklists, with an emphasis on selecting vouchers based on occurrence records that can be verified for identification accuracy. Advantages and limitations of creating checklists in Symbiota versus traditional ways of compiling these lists are discussed. Traditional checklists are well suited to document current knowledge as a ‘snapshot in time’. They are important baselines, frequently used by ecologists and conservation scientists as an established naming convention for citing species reported from a country. Compiling these lists, however, requires an immense effort, only to inadequately address the dynamic nature of scientific discovery. Traditional checklists are thus quickly out of date, particularly in groups with rapidly changing taxonomy, such as lichenized fungi. Especially in megadiverse countries, where new species and new occurrences continue to be discovered, traditional checklists are not easily updated; these lists necessarily fall short of efficiently managing immense data sets, and they rely primarily on secondary evidence (i.e. literature records rather than specimens). Ideally, best practices make use of dynamic database platforms such as Symbiota to assess occurrence records based both on literature citations and voucher specimens. Using modern data management tools comes with a learning curve. Systems like Symbiota are not necessarily intuitive and their functionality can still be improved, especially when handling literature records. However, online biodiversity data platforms have much potential in more efficiently managing and assessing large biodiversity data sets, particularly when investigating the lichen biota of megadiverse countries such as Ecuador
What Do the First 597 Global Fungal Red List Assessments Tell Us about the Threat Status of Fungi?
Fungal species are not immune to the threats facing animals and plants and are thus also prone to extinction. Yet, until 2015, fungi were nearly absent on the IUCN Red List. Recent efforts to identify fungal species under threat have significantly increased the number of published fungal assessments. The 597 species of fungi published in the 2022-1 IUCN Red List update (21 July 2022) are the basis for the first global review of the extinction risk of fungi and the threats they face. Nearly 50% of the assessed species are threatened, with 10% NT and 9% DD. For regions with a larger number of assessments (i.e., Europe, North America, and South America), subanalyses are provided. Data for lichenized and nonlichenized fungi are also summarized separately. Habitat loss/degradation followed by climate change, invasive species, and pollution are the primary identified threats. Bias in the data is discussed along with knowledge gaps. Suggested actions to address these gaps are provided along with a discussion of the use of assessments to facilitate on-the-ground conservation efforts. A research agenda for conservation mycology to assist in the assessment process and implementation of effective species/habitat management is presented
Teloschistaceae (lichenized Ascomycota) from the Galapagos Islands : a phylogenetic revision based on morphological, anatomical, chemical, and molecular data
The lichen family Teloschistaceae from the Galapagos is revised. Most of the species belong to the Caloplacoideae, two to Teloschistoideae and a few to Xanthorioideae, three subfamilies not validly published, which is remedied here. Four different datasets were analyzed using Bayesian inference. For the bulk of the species, a combined dataset of nrITS, nrLSU and mrSSU was analyzed. Additionally, three analyses were performed using nrITS to further investigate phylogenetic relationships within and between species in each subfamily, and in the genera Xanthomendoza and Squamulea. Four new gen- era are described: Lacrima, Oceanoplaca, Phaeoplaca, Sucioplaca. Twenty-four species are reported, of which ten are new to science: Caloplaca nigra, Lacrima galapagoensis, Oceanoplaca chemoisidiosa, O. sideritoides, Phaeoplaca tortuca, Squamulea chelonia, S. humboldtiana, S. osseophila, S. oceanica, and Xanthomendoza leoncita. Several new combinations are proposed and three species of Xanthomendoza are reduced to synonymy. Several new combinations and species placed into synonymy do not occur in the Galapagos, but are treated as a consequence of our taxonomic revision. Morphology, anatomy, secondary chemistry, distribution and molecular phylogenetic affiliation are presented for each species and a key is provided. Eight different chemical patterns are quantitatively described based on HPLC analyses. The new genus Lacrima includes L. galapagoensis, a species without vegetative propagules, and two densely isidiate species, L. epiphora and L. aphanotripta that are morphologically similar to ‘Caloplaca’ wrightii. The only species of Galapagos Teloschistaceae that contains xanthones is placed into Huneckia. Oceanoplaca includes two species with the new anthraquinone isidiosin, O. isidiosa and O. chemoisidiosa, while a third species, O. sideritoides, does not contain this secondary metabolite. Phaeoplaca camptidia has previously been reported from Galapagos, but our phylogenetic analysis suggests that it is a new species, here named P. tortuca. An isolated position is occupied by ‘Caloplaca’ diplacia, which we place in it its own monotypic genus Sucioplaca. Some Galapagos Teloschistaceae can be considered a ‘residue’ of unresolved Caloplaca s.l., i.e. the corticolous C. floridana is possibly related to the saxicolous C. nigra, while C. cupuli fera can currently not be placed. Squamulea remains particularly problematic and includes S. phyllidizans, that is nested among otherwise unresolved Squamulea species. Based on molecular data, S. phyllidizans is close to ‘Huriella’. ‘Huriella’ flakusii, described from Peru, is confirmed to occur in the Galapagos and the genus is reduced to synonymy with Squamulea. The Squamulea squamosa/subsoluta group remains largely unresolved, but the new species S. chelonia, S. humboldtiana, S. oceanica, and S. osseophila are phylogeneti- cally distinct. Foliose Teloschistaceae are represented only by one species, described as Xanthomendoza leoncita, while the only fruticose species, Teloschistes chrysophthalmus and T. flavicans, are cosmopolitan.
Obscuroplaca gen. nov. – a replacement name for Phaeoplaca; Teloschistaceae (lichenized Ascomycota) from the Galapagos Islands
A replacement name Obscuroplaca for the illegitimate genus Phaeoplaca is introduced. The three known species are transferred as Obscuroplaca camptidia, O. ochrolechioides, and O. tortuca
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