17 research outputs found

    Globally invariant metabolism but density-diversity mismatch in springtails.

    Get PDF
    Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning

    Global fine-resolution data on springtail abundance and community structure

    Get PDF
    Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.</p

    Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

    Get PDF
    IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

    Gypsy

    No full text
    Gift of Dr. Mary Jane Esplen.Piano vocal ukulele [instrumentation]This great big world all before you ev'ry you may roam [first line]Gypsy you have no destination gypsy your haven [first line of chorus]C major [key]Moderato [tempo]Popular song [form/genre]Woman, guitar, trailer, tree, Whiteman caricature [illustration]Publisher's advertisement on back cover [note

    Towards a global synthesis of Collembola knowledge – challenges and potential solutions

    Get PDF
    Collembola are among the most abundant and diverse soil microarthropods, which are found in almost all (semi)terrestrial environments and often serve as model organisms in empirical studies. Diverse data collected on the biology and ecology of Collembola over the last century are waiting for synthesis studies, while developing technologies may facilitate generation of new knowledge. Collembola research in 2020 is entering the stage of global synthesis and in this opinion paper we address the main challenges that the community of collembologists is facing on this avenue. We first discuss the present status and social context of Collembola taxonomy and the potential use of novel technologies to describe new species. We then focus on aspects of community ecology, reviewing the processes of dispersal, environmental and biotic filtering, from the spatial scale of microhabitat to the globe. We also discuss the involvement of Collembola in ecosystem processes and which proxies, such as functional traits, can be used to predict the functional roles of species. Finally, we provide recommendations on how we can improve community data collection by using standard methods and better data handling practices. We call for (1) integrating morphological descriptions with high-resolution photographs and genetic barcodes for species descriptions and developing of user friendly software and machine learning approaches to facilitate deposition of structured taxonomic knowledge on web platforms; (2) multiscale studies on biodiversity distribution and community processes, especially including dispersal mechanisms; (3) recording and sharing functional, not only morphological, trait data in controlled experiments and field surveys; (4) knowledge synthesis and meta-analysis studies on the topics of ecosystem roles of Collembola, conservation of its diversity, feeding behaviour, protection mechanisms and dispersal of different Collembola species, and effects of land use and climate change on collembolan communities; (5) joint efforts in covering the gaps in Collembola knowledge, especially in underexplored regions (predominantly tropics and subtropics) using standard methodologies; (6) data sharing and its integration in open structured databases. We believe that Collembola studies could make use of new technologies and ongoing changes in society. To facilitate the progress across these research topics by 2040, we have established #GlobalCollembola, a distributed-effort community-driven initiative that aims to provide open and global data on Collembola taxonomic and genetic diversity, abundance, traits and literature and to coordinate global efforts in covering the key knowledge gaps

    Globally invariant metabolism but density-diversity mismatch in springtails

    No full text
    Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning.ISSN:2041-172
    corecore