382 research outputs found
Phylogenetic diversity in conservation: A brief history, critical overview, and challenges to progress – Authors response to reviewers
No full textCardillo M (2023). Phylogenetic diversity in conservation: A brief history, critical overview, and challenges to progress. Cambridge Prisms: Extinction 1, e11
Geographic Range Shifts Do Not Erase the Historic Signal of Speciation in Mammals This content downloaded from 150. Geographic Range Shifts Do Not Erase the Historic Signal of Speciation in Mammals
No full textJSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . Online enhancements: appendix tables, zip file. abstract: Many evolutionary analyses assume that the positions of species geographic ranges are sufficiently phylogenetically conserved that current ranges reflect ancestral ranges and retain the historic signal of speciation. The validity of this assumption has been challenged, because there is evidence that ranges can shift rapidly and extensively. Here I test the assumption of range conservatism using simulations and empirical tests of phylogenetic signal in geographic positions of ranges within mammal orders, families, and genera. In most taxa, range positions show strong phylogenetic signal, quantified using Pagel's l, Mantel tests, and a novel method to measure phylogenetic signal near the tips of a phylogeny. Taxa with highly labile range positions are exceptions to the general pattern and include very young groups such as Sciurus that may still be in the early, rapid-expansion phase of adaptive radiation. In two orders containing many species with large distributions (Artiodactyla and Carnivora), temporal patterns of range evolution are consistent with large instantaneous shifts in range position associated with allopatric speciation. In most other taxa, range evolution is better described by models that allow ranges to evolve along branches of the phylogeny. The results point to a common pattern of phylogenetically conserved ranges where the current position of species ranges reflects their position at the time of speciation, modified by gradual drift of range boundaries through time
Evolution of a hotspot genus: geographic variation in speciation and extinction rates in Banksia (Proteaceae)
No full textBACKGROUND Hotspots of angiosperm species richness and endemism in Mediterranean-climate regions are among the most striking, but least well-understood, geographic patterns of biodiversity. Recent studies have emphasized the importance of rapid diversification within hotspots, compared to non-hotspot regions, as a major contributor to these patterns. We constructed the first near-complete phylogeny of Banksia (Proteaceae) to test whether diversification rates have differed between lineages confined to the southwest Australian hotspot and those found throughout southern, eastern and northern Australia. We then tested for variation in diversification rates among the bioclimatic zones within the southwest hotspot itself. RESULTS Although Banksia species richness in the southwest is ten times that of the rest of the continent, we find little evidence for more rapid diversification in the southwest, although this result is inconclusive. However, we find firmer support for substantial rate variation within the southwest hotspot, with more rapid diversification in the semi-arid heaths and shrublands, compared to the high-rainfall forests. Most of the Banksia diversity of the southwest appears to be generated in the heaths and shrublands, with a high migration rate out of this zone boosting diversity of the adjacent forest zone. CONCLUSIONS The geographic pattern of diversification in Banksia appears more complex than can be characterized by a simple hotspot vs. non-hotspot comparison, but in general, these findings contrast with the view that the high diversity of Mediterranean hotspots is underpinned by rapid radiations. Steady accumulation of species at unexceptional rates, but over long periods of time, may also have contributed substantially to the great botanical richness of these regions.The work was funded by an Australian Research Council Discovery Grant and QEII Fellowship to M. Cardillo (DP0879971), with additional funding provided by the Research School of Biology at the Australian National University
Finite Element Method Analysis applied to the Study of a Corner Joint in Reinforced Concrete Structures
No full textThe principal objective for this work was to extend the field of application of FEM to space frame beam-column connections under static loading and with lateral displacements. A four-storey building was modelled under static load condition. Horizontal and vertical structural elements were designed according to Eurocode 2. In order to understand the behavior of the external node made by under column, two beam and upper column, two models using correct boundary condition and nonlinear behavior of materials have been done using Abaqus Software The analysis was performed on an interior and an exterior joint models each in two conditions: unconfined and confined joint varying the distributions of number of stirrups for the beam reinforcement and the column reinforcement .A sup structural model to submit to numerical analysis have been performed, the Concrete Damage Plasticity model (CDPM) has been chosen for fit the nonlinear behavior for the concrete and the elastoplastic model has been adopted for the nonlinear behavior for the reinforcement (stirrups, longitudinal and vertical bars). The models were then verified against already existing and validated analytical results and results of experiments conducted on specimen
The phylogenetic signal of species co-occurrence in high-diversity shrublands: different patterns for fire-killed and fire-resistant species
No full textAbstract Background Using phylogenies in community ecology is now commonplace, but typically, studies assume and test for a single common phylogenetic signal for all species in a community, at a given scale. A possibility that remains little-explored is that species differing in demographic or ecological attributes, or facing different selective pressures, show different community phylogenetic patterns, even within the same communities. Here I compare community phylogenetic patterns for fire-killed and fire-resistant Banksia species in the fire-prone shrublands of southwest Australia. Results Using new Bayesian phylogenies of Banksia, together with ecological trait data and abundance data from 24 field sites, I find that fire regeneration mode influences the phylogenetic and phenotypic signal of species co-occurrence patterns. Fire-killed species (reseeders) show patterns of phylogenetic and phenotypic repulsion consistent with competition-driven niche differentiation, but there are no such patterns for fire-resistant species (resprouters). For pairs of species that differ in fire response, co-occurrence is mediated by environmental filtering based on similarity in edaphic preferences. Conclusions These results suggest that it may be simplistic to characterize an entire community by a single structuring process, such as competition or environmental filtering. For this reason, community analyses based on pairwise species co-occurrence patterns may be more informative than those based on whole-community structure metrics.</p
A novel approach for global mammal extinction risk reduction
No full textWith one-fourth of the world’s mammals threatened with extinction and limited budget to save them, adopting an efficient conservation strategy is crucial. Previous approaches to setting global conservation priorities have assumed all species to have equal conservation value, or have focused on species with high extinction risk, species that may be hard to save. Here, we identify priority species for optimizing the reduction in overall extinction risk of the world’s threatened terrestrial mammals. We take a novel approach and focus on species having the greatest recovery opportunity using a new conservation benefit metric: the Extinction risk Reduction Opportunity (ERO). We discover that 65–87% of all threatened and potentially recoverable species are overlooked by existing prioritization approaches. We use the ERO metric to prioritize threatened species, but the potential applications are broader; ERO has the potential to integrate with every strategy that aims to maximize the likelihood of conservation success
Authors, languages and potential translations in Ibero-American cultural periodicals (1898-1959), with VIAF linked author data
No full textThe dataset provides data on contributors—authors of contributions/articles—to Ibero-American cultural periodicals from the first half of 20th century. Using basic information like article titles and authorship as a starting point, we have retrieved a set of 60987 potential authors to 292186 articles in 309 periodicals published between 1898 and 1959, held in online repositories or libraries located in Argentina, Spain, Portugal, and Germany, all related to Spanish-speaking and Lusophone literary and cultural magazines. By applying machine learning and natural language processing tools, as well as by linking the author's names against the Virtual International Authority File (VIAF), we provide enriched information on gender, language, and nationality for about 66% of the initially identified contributor names, responsible for about 26% of the articles. We identify potential translations—loosely defined as texts published in a language different from the author’s native or writing language—and the presence of foreign authors in the Ibero-American cultural press
Market Reaction to the Expected Loss Model in Banks
No full textThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordWe investigate how investors perceive the adoption of the expected-loss model (ELM) for impairment incorporated in IFRS 9. Using a sample of European listed banks covering the period of the standard-setting process of IFRS 9, we examine whether the market perceives the new regulation to increase shareholder wealth. First, we document a positive market reaction to the ELM adoption events. Second, we find that investors perceive that the potential benefits of ELM are more pronounced for larger banks, banks with lower profitability and higher systemic risk, and for those that received a public bailout and with more positively skewed returns. Overall, these results support a “monitoring” channel suggesting that ELM may lead to greater bank transparency and more effective market discipline, fundamental for improving financial stability
Supplementary data from 'Predicting the distribution of Australian frogs and their overlap with Batrachochytrium dendrobatidis under climate change'
No full textAim: Amphibians, with over 40% of assessed species listed as threatened, are disproportionately at risk in the global extinction crisis. Among the many factors implicated in the current and ongoing loss of amphibian biodiversity are climate change and the disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd). These two threats are of particular concern in Australia, where Bd has been implicated in the declines of at least 43 frog species, and climate change is emerging as an additional threat. Here, we explore how climate change is likely to affect the distributions of Australian frog species and Bd to the year 2100, as well as how the spatial and climatic niche overlap between chytridiomycosis-declined frogs and Bd could shift.
Location: Australia
Methods: We used species distribution modelling to infer the current and future distribution of 141 Australian frog species and Bd, under two emissions scenarios. We used metrics of niche similarity, including Schoener's D and the Niche Margin Index, to quantify predicted alterations to spatial interactions between Bd and frog species.
Results: Climate change is likely to have a variable impact on frog distributions in Australia, with some 23 and 47 species, primarily in southern Australia, predicted to lose at least 30% of their current distributions under low and high emissions scenarios, respectively. In contrast, 69 and 68 species, respectively, have potential to increase their distributions, primarily in northern Australia. While the distribution of Bd is predicted to decrease, the proportional spatial and niche overlap between Bd and susceptible frog species is predicted to remain little changed, and in some cases, to increase.
Main conclusions: Although effects will be variable across the continent, climate change is likely to be a threatening factor to a number of Australian frog species. Additionally, chytridiomycosis is likely to remain a significant threat to many frog species, as any reductions to the pathogen's distribution largely coincide with geographic range contractions of chytridiomycosis-susceptible species.Supplementary data from 'Predicting the distribution of Australian frogs and their overlap with Batrachochytrium dendrobatidis under climate change'.
Supplementary scripts from 'Predicting the distribution of Australian frogs and their overlap with Batrachochytrium dendrobatidis under climate change'.
Attached scripts can be completed in sequential order, using the supplementary data provided in our paper Sopniewski, J., Scheele, B. C., and Cardillo, M. (2022), to reproduce results.
IBRA bioregions can be downloaded from: https://www.awe.gov.au/agriculture-land/land/nrs/science/ibra#ibra
IUCN data can be downloaded from: https://www.iucnredlist.org/
WorldClim data (current) can be downloaded from: https://www.worldclim.org/
WorldClim data (future) can be downloaded from: https://www.worldclim.org/data/cmip6/cmip6climate.htm
The life-history basis of latitudinal diversity gradients: how do species traits vary from the poles to the equator.
No full text1. Latitudinal variation among species in life-history traits is often suggested to contribute to high tropical species richness. However, traditional methods of analysing such variation rarely control for phylogeny and latitudinal range overlap between species, potentially giving misleading results. 2. Using a method of pairwise independent contrasts which overcomes these problems, I tested for latitudinal variation among bird species in a number of traits which have been linked, theoretically or empirically, with both latitude and species richness. 3. This method indicates strong support for Rapoport's Rule and decreasing clutch size towards the equator in both hemispheres, but only partial support for decreasing body size and ecological generalism towards the equator. 4. Indirect measures of sexual selection (sexual dichromatism and size dimorphism) show no variation with latitude; an apparent increase in dichromatism towards the equator is shown to be an artefact of phylogeny. 5. Many of the associations between life history and latitude were not detected by traditional cross-species analyses, highlighting the importance of incorporating phylogeny and overlap in studies of geographical life-history variation. Establishing associations between life-history traits and latitude does not prove, but is a necessary prerequisite for., a link between these traits and latitudinal diversity gradients
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