40 research outputs found
The role of biotic interactions in shaping distributions and realised assemblages of species: implications for species distribution modelling.
Predicting which species will occur together in the future, and where, remains one of the greatest challenges in ecology, and requires a sound understanding of how the abiotic and biotic environments interact with dispersal processes and history across scales. Biotic interactions and their dynamics influence species' relationships to climate, and this also has important implications for predicting future distributions of species. It is already well accepted that biotic interactions shape species' spatial distributions at local spatial extents, but the role of these interactions beyond local extents (e.g. 10 km(2) to global extents) are usually dismissed as unimportant. In this review we consolidate evidence for how biotic interactions shape species distributions beyond local extents and review methods for integrating biotic interactions into species distribution modelling tools. Drawing upon evidence from contemporary and palaeoecological studies of individual species ranges, functional groups, and species richness patterns, we show that biotic interactions have clearly left their mark on species distributions and realised assemblages of species across all spatial extents. We demonstrate this with examples from within and across trophic groups. A range of species distribution modelling tools is available to quantify species environmental relationships and predict species occurrence, such as: (i) integrating pairwise dependencies, (ii) using integrative predictors, and (iii) hybridising species distribution models (SDMs) with dynamic models. These methods have typically only been applied to interacting pairs of species at a single time, require a priori ecological knowledge about which species interact, and due to data paucity must assume that biotic interactions are constant in space and time. To better inform the future development of these models across spatial scales, we call for accelerated collection of spatially and temporally explicit species data. Ideally, these data should be sampled to reflect variation in the underlying environment across large spatial extents, and at fine spatial resolution. Simplified ecosystems where there are relatively few interacting species and sometimes a wealth of existing ecosystem monitoring data (e.g. arctic, alpine or island habitats) offer settings where the development of modelling tools that account for biotic interactions may be less difficult than elsewhere
Field Measurements of Terrestrial and Martian Dust Devils
Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types
Modelling the sulfate capacity of simulated radioactive waste borosilicate glasses
The capacity of simulated high-level radioactive waste borosilicate glasses to incorporate sulfate has been studied as a function of glass composition. Combined Raman, 57Fe Mössbauer and literature evidence supports the attribution of coordination numbers and oxidation states of constituent cations for the purposes of modelling, and results confirm the validity of correlating sulfate incorporation in multicomponent borosilicate radioactive waste glasses with different models. A strong compositional dependency is observed and this can be described by an inverse linear relationship between incorporated sulfate (mol% SO42−) and total cation field strength index of the glass, Σ(z/a2), with a high goodness-of-fit (R2 ≈ 0.950). Similar relationships are also obtained if theoretical optical basicity, Λth (R2 ≈ 0.930) or non-bridging oxygen per tetrahedron ratio, NBO/T (R2 ≈ 0.919), are used. Results support the application of these models, and in particular Σ(z/a2), as predictive tools to aid the development of new glass compositions with enhanced sulfate capacities
Global maps of soil temperature.
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km <sup>2</sup> resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km <sup>2</sup> pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
A Comprehensive Pan-Cancer Molecular Study of Gynecologic and Breast Cancers
We analyzed molecular data on 2,579 tumors from The Cancer Genome Atlas (TCGA) of four gynecological types plus breast. Our aims were to identify shared and unique molecular features, clinically significant subtypes, and potential therapeutic targets. We found 61 somatic copy-number alterations (SCNAs) and 46 significantly mutated genes (SMGs). Eleven SCNAs and 11 SMGs had not been identified in previous TCGA studies of the individual tumor types. We found functionally significant estrogen receptor-regulated long non-coding RNAs (lncRNAs) and gene/lncRNA interaction networks. Pathway analysis identified subtypes with high leukocyte infiltration, raising potential implications for immunotherapy. Using 16 key molecular features, we identified five prognostic subtypes and developed a decision tree that classified patients into the subtypes based on just six features that are assessable in clinical laboratories. By performing molecular analyses of 2,579 TCGA gynecological (OV, UCEC, CESC, and UCS) and breast tumors, Berger et al. identify five prognostic subtypes using 16 key molecular features and propose a decision tree based on six clinically assessable features that classifies patients into the subtypes
Changes in forest plant communities with recent climate warming in Jura Moutains (France and Switzerland).
Hammering, mauling, and kissing : stereotyped courtship behaviour in Cardiocondyla ants.
Conversion chimique des revêtements zingués. caractérisation des substrats traités et mesure d’adhérence de systèmes peints
La phosphatation de revêtements zingués est étudiée à l’aide de techniques électrochimique (mesure du potentiel d’abandon) et électrique (impédancemétrie) permettant de suivre la formation de la couche in situ, et par des techniques de caractérisation de surface (MEB, SDL, LEEIXS) et de mesure d’adhérence (flexion trois points) avant ou après traitement. L’utilisation de ces techniques, (qui sont complémentaires) nous a permis de mettre en évidence l’influence des prétraitements (dégraissages, affinage) et de l’addition de fluorures (dans le bain phosphatant) sur la phosphatation
Yielding of metallic glass foam by percolation of an elastic buckling instability
International audienc
Identification d’une nouvelle phéromone larvaire : l’E-β-ocimene permettant la régulation du développement ovarien des ouvrières chez l’abeille domestique
National audienceDans une colonie d’abeilles sans reine ni couvain, les ouvrières tendent à devenir fertiles et investir leur énergie dans la ponte d’oeuf non-fécondés. Afin de maintenir une certaine stabilité dans l’organisation de la colonie et prévenir ce détournement de l’investissement énergétique des ouvrières, la reine garantie son statut de seule reproductrice et le couvain accapare le soin des ouvrières. Pour cela, ils émettent des phéromones peu volatiles. La phéromone mandibulaire (principalement le 9-ODA) émis par la reine ainsi qu’un mélange de 10 esters émis par le couvain. Ces composés permettent une castration chimique partielle des ouvrières. Cependant, parmi les deux facteurs de régulation de la maturation ovarienne des ouvrières, il semble que la présence de couvain soit le plus actif. Nous nous sommes donc demandé si les larves ne pourraient pas émettre des molécules très volatiles ayant un rôle sur le développement ovarien des ouvrières. Les composés volatiles larvaires ont donc été prélevés par Microextraction sur phase solide (SPME), puis analysés et identifiés par GC-MS. Le pic majeur retrouvé dans tous les échantillons est une molécule hautement volatile, l’E-β- ocimene. Nous avons testé l’effet de cette molécule sur la croissance des ovaires d’ouvrières élevées en cagette. Les résultats indiquent un effet inhibiteur significatif de l’E-β-ocimene sur le développement ovarien des ouvrières. Cette nouvelle phéromone, dont les effets sont identiques à ceux produits par la phéromone mandibulaire de la reine, montre que différents acteurs, utilisant différentes phéromones, peuvent induire un même effet sur le même organisme cible. De nouveaux tests sont nécessaires pour comprendre si les trois phéromones décris ici, régulant la fertilité de la colonie d’abeilles, peuvent agir ensemble pour une castration chimique totale des ouvrière