328 research outputs found

    Global priorities for conservation across multiple dimensions of mammalian diversity

    Get PDF
    Conservation priorities that are based on species distribution, endemism, and vulnerability may underrepresent biologically unique species as well as their functional roles and evolutionary histories. To ensure that priorities are biologically comprehensive, multiple dimensions of diversity must be considered. Further, understanding how the different dimensions relate to one another spatially is important for conservation prioritization, but the relationship remains poorly understood. Here, we use spatial conservation planning to (i) identify and compare priority regions for global mammal conservation across three key dimensions of biodiversity-taxonomic, phylogenetic, and traits-and (ii) determine the overlap of these regions with the locations of threatened species and existing protected areas. We show that priority areas for mammal conservation exhibit low overlap across the three dimensions, highlighting the need for an integrative approach for biodiversity conservation. Additionally, currently protected areas poorly represent the three dimensions of mammalian biodiversity. We identify areas of high conservation priority among and across the dimensions that should receive special attention for expanding the global protected area network. These high-priority areas, combined with areas of high priority for other taxonomic groups and with social, economic, and political considerations, provide a biological foundation for future conservation planning efforts

    Habitat availability for amphibians and extinction threat: A global analysis

    Get PDF
    Aim: Habitat loss and degradation are the factors threatening the largest number of amphibian species. However, quantitative measures of habitat availability only exist for a small subset of them. We evaluated the relationships between habitat availability, extinction risk and drivers of threat for the world's amphibians. We developed deductive habitat suitability models to estimate the extent of suitable habitat and the proportion of suitable habitat (PSH) inside the geographic range of each species, covering species and areas for which little or no high-resolution distribution data are available. Location: Global. Methods: We used information on habitat preferences to develop habitat suitability models at 300-m resolution, by integrating range maps with land cover and elevation. Model performance was assessed by comparing model output with point localities where species were recorded. We then used habitat availability as a surrogate of area of occupancy. Using the IUCN criteria, we identified species having narrow area of occupancy, for which extinction risk is likely underestimated. Results: We developed models for 5363 amphibians. Validation success of models was high (94%), being better for forest specialists and generalists than for open habitat specialists. Generalists had proportionally more habitat than forest or open habitat specialists. The PSH was lower for species having small geographical ranges, currently listed as threatened, and for which habitat loss is recognized as a threat. Differences in habitat availability among biogeographical realms were strong. We identified 61 forest species for which the extinction risk may be higher that currently assessed in the Red List, due to limited extent of suitable habitat. Main conclusions: Habitat models can accurately predict amphibian distribution at fine scale and allow describing biogeographical patterns of habitat availability. The strong relationship between amount of suitable habitat and extinction threat may help the conservation assessment in species for which limited information is currently available

    Ad hoc tailored electrocatalytic MnO2nanorods for the oxygen reduction in aqueous and organic media

    Get PDF
    Metal-air batteries are one of the most promising electrochemical systems for energy storage and conversion. Herein we report promising results by exploiting manganese dioxide nanoparticles as ORR electrocatalysts. MnO2 nanorods were prepared through a hydrothermal synthesis, i.e. by varying both the salt precursors (Le. manganese sulphate or chloride) and the oxidizing agents (Le. ammonium persulfate or potassium permanganate). All the nanopowders were finely characterized on structural, morphological and surface points of view. Then, their electrocatalytic power was tested either in aqueous 0.1 M potassium hydroxide or in Tetra Ethylene Glycol Dimethyl Ether (TEGDME)/LiNO3 0.5 M electrolytes, by using Gas Diffusion Electrodes (GDEs) and Glassy Carbon (GC) as cathodes, respectively. All the nanoparticles promoted the ORR by causing a shift of the onset potential up to 100 mV in both solvents. Nevertheless, this shift was different according to the solvent/electrolyte used: in the case of the ether-based solvent, different values are obtained by adopting the synthesized MnO2 powders. Thus, we hypothesized that the structural/surface properties of MnO2 samples are leveled in the aqueous medium (Le. in a OH rich solvent, the hydroxyls can interact with the homologs on the MnO2 surface), contrary to what occurs in the organic solvent. Furthermore, a different behavior was observed also on the kinetic point of view thus leading to diverse interpretations of the oxygen reduction mechanism, especially in TEGDME

    Chlorine Dioxide Degradation Issues on Metal and Plastic Water Pipes Tested in Parallel in a Semi-Closed System

    Get PDF
    Chlorine dioxide (ClO2) has been widely used as a disinfectant in drinking water in the past but its effects on water pipes have not been investigated deeply, mainly due to the difficult experimental set-up required to simulate real-life water pipe conditions. In the present paper, four different kinds of water pipes, two based on plastics, namely random polypropylene (PPR) and polyethylene of raised temperature (PERT/aluminum multilayer), and two made of metals, i.e., copper and galvanized steel, were put in a semi-closed system where ClO2 was dosed continuously. The semi-closed system allowed for the simulation of real ClO2 concentrations in common water distribution systems and to simulate the presence of pipes made with different materials from the source of water to the tap. Results show that ClO2 has a deep effect on all the materials tested (plastics and metals) and that severe damage occurs due to its strong oxidizing power in terms of surface chemical modification of metals and progressive cracking of plastics. These phenomena could in turn become an issue for the health and safety of drinking water due to progressive leakage of degraded products in the water

    The role of surface electrification on the growth and structural features of titania nanoparticles

    Get PDF
    TiO2 particles, prepared by following a sol-gel preparative route, were submitted to hydrothermal steps performed at solution pH values corresponding, respectively, to positive, zero and negative oxide surface charges. After the hydrothermal step all the samples were thermally treated at 300 and 600degreesC, for the same length of time (6 h). The powders, both precursors and calcined samples, were characterized for phase composition-crystallinity. particle morphology and surface electrification features. The role played by the particles electrification during the hydrothermal step in affecting the physico-chemical properties of the powders is discussed

    Post-2020 biodiversity targets need to embrace climate change

    Get PDF
    Recent assessment reports by the Intergovernmental Panel on Climate Change (IPCC) and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) have highlighted the risks to humanity arising from the unsustainable use of natural resources. Thus far, land, freshwater, and ocean exploitation have been the chief causes of biodiversity loss. Climate change is projected to be a rapidly increasing additional driver for biodiversity loss. Since climate change and biodiversity loss impact human societies everywhere, bold solutions are required that integrate environmental and societal objectives. As yet, most existing international biodiversity targets have overlooked climate change impacts. At the same time, climate change mitigation measures themselves may harm biodiversity directly. The Convention on Biological Diversity's post-2020 framework offers the important opportunity to address the interactions between climate change and biodiversity and revise biodiversity targets accordingly by better aligning these with the United Nations Framework Convention on Climate Change Paris Agreement and the Sustainable Development Goals. We identify the considerable number of existing and proposed post- 2020 biodiversity targets that risk being severely compromised due to climate change, even if other barriers to their achievement were removed. Our analysis suggests that the next set of biodiversity targets explicitly addresses climate change-related risks since many aspirational goals will not be feasible under even lower-end projections of future warming. Adopting more flexible and dynamic approaches to conservation, rather than static goals, would allow us to respond flexibly to changes in habitats, genetic resources, species composition, and ecosystem functioning and leverage biodiversity's capacity to contribute to climate change mitigation and adaptation

    Designing materials by means of the cavity-microelectrode : the introduction of the quantitative rapid screening toward a highly efficient catalyst for water oxidation

    Get PDF
    In this paper, we introduce the concept and the methodology of quantitative rapid screening (QRS) of catalysts. It is based on the use of the cavity-microelectrode (C-ME), a tool that hosts a known amount of powder and can be filled and emptied quickly, thus allowing the quantitative, rapid, fine characterization of different materials. Here, C-MEs are used for selecting a suitable material to be used as electrocatalyst for the oxygen evolution reaction (water oxidation) in acidic environment, a key process for the majority of the industrial electrolytic applications including the production of high purity hydrogen. A matrix of materials, each having the same low iridium oxide content, is quantitatively screened for finding the most promising one. C-MEs allowed us to measure the effective number of active Ir sites and their surface concentration. The success of this strategy is proven by the good performance of the \u2018\u2018best\u2019\u2019 material when tested in a proton exchange membrane water electrolyzer, that allowed high hydrogen fluxes at a low cell potential ( 4000 dm3 h 1 m 2 at less than 1.9 V)

    Conserving biodiversity in production landscapes

    Get PDF
    Alternative land uses make different contributions to the conservation of biodiversity and have different implementation and management costs. Conservation planning analyses to date have generally assumed that land is either protected or unprotected and that the unprotected portion does not contribute to conservation goals. We develop and apply a new planning approach that explicitly accounts for the contribution of a diverse range of land uses to achieving conservation goals. Using East Kalimantan (Indonesian Borneo) as a case study, we prioritize investments in alternative conservation strategies and account for the relative contribution of land uses ranging from production forest to well-managed protected areas. We employ data on the distribution of mammals and assign species-specific conservation targets to achieve equitable protection by accounting for life history characteristics and home range sizes. The relative sensitivity of each species to forest degradation determines the contribution of each land use to achieving targets. We compare the cost effectiveness of our approach to a plan that considers only the contribution of protected areas to biodiversity conservation, and to a plan that assumes that the cost of conservation is represented by only the opportunity costs of conservation to the timber industry. Our preliminary results will require further development and substantial stakeholder engagement prior to implementation; nonetheless we reveal that, by accounting for the contribution of unprotected land, we can obtain more refined estimates of the costs of conservation. Using traditional planning approaches would overestimate the cost of achieving the conservation targets by an order of magnitude. Our approach reveals not only where to invest, but which strategies to invest in, in order to effectively and efficiently conserve biodiversity. Copyright ESA. All rights reserved

    Measurement of pH. Definition, Standards, and Procedures

    Get PDF
    The definition of a “primary method of measurement” [1] has permitted a full consideration of the definition of primary standards for pH, determined by a primary method (cell without transference, Harned cell), of the definition of secondary standards by secondary methods, and of the question whether pH, as a conventional quantity, can be incorporated within the internationally accepted system of measurement, the International System of Units (SI, SystĂšme International d’UnitĂ©s). This approach has enabled resolution of the previous compromise IUPAC 1985 Recommendations [2]. Furthermore, incorporation of the uncertainties for the primary method, and for all subsequent measurements, permits the uncertainties for all procedures to be linked to the primary standards by an unbroken chain of comparisons. Thus, a rational choice can be made by the analyst of the appropriate procedure to achieve the target uncertainty of sample pH. Accordingly, this document explains IUPAC recommended definitions, procedures, and terminology relating to pH measurements in dilute aqueous solutions in the temperature range 5–50 °C. Details are given of the primary and secondary methods for measuring pH and the rationale for the assignment of pH values with appropriate uncertainties to selected primary and secondary substances

    Climate change modifies risk of global biodiversity loss due to land-cover change

    Get PDF
    Climate change and land-cover change will have major impacts on biodiversity persistence worldwide. These two stressors are likely to interact, but how climate change will mediate the effects of land-cover change remains poorly understood. Here we use an empirically-derived model of the interaction between habitat loss and climate to predict the implications of this for biodiversity loss and conservation priorities at a global scale. Risk analysis was used to estimate the risk of biodiversity loss due to alternative future land-cover change scenarios and to quantify how climate change mediates this risk. We demonstrate that the interaction of climate change with land-cover change could increase the impact of land-cover change on birds and mammals by up to 43% and 24% respectively and alter the spatial distribution of threats. Additionally, we show that the ranking of global biodiversity hotspots by threat depends critically on the interaction between climate change and habitat loss. Our study suggests that the investment of conservation resources will likely change once the interaction between climate change and land-cover change is taken into account. We argue that global conservation efforts must take this into account if we are to develop cost-effective conservation policies and strategies under global change
    • 

    corecore