Abstract:Carbon-14 measurements on 231 elephant ivory specimens from 14 large ivory seizures (≥0.5 ton) made between 2002 and 2014 show that most ivory (ca. 90%) was derived from animals that had died less than 3 y before ivory was confiscated. This indicates that the assumption of recent elephant death for mortality estimates of African elephants is correct: Very little “old” ivory is included in large ivory shipments from Africa. We found only one specimen of the 231 analyzed to have a lag time longer than 6 y. Patte… Show more
“…1,2 High-precision measurements also have applications in forensic science and illicit trade. 3 These applications in quantitative 14 C science require world-wide intercomparisons between measurement facilities, specifically for facilities performing liquid scintillation counting and accelerator mass spectrometer (AMS). 4 Recent AMS intercomparisons have focused on high-precision (≤1 %) applications in atmospheric 14 C science, where agreed-upon standards for gas handling, sample preparation, and calibration are needed to realize ultimate sensitivities.…”
High-precision measurements of radiocarbon (14C ) near or below a fraction modern 14C of one (F14C ≤ 1) are challenging and costly. An accurate, ultra-sensitive linear absorption approach to detecting 14C would provide a simple and robust bench-top alternative to off-site accelerator mass spectrometry facilities. Here we report the quantitative measurement of 14C in gas-phase samples of CO2 with F14C < 1 using cavity ring-down spectroscopy in the linear absorption regime. Repeated analysis of CO2 derived from the combustion of either biogenic or petrogenic sources revealed a robust ability to differentiate samples with F14C < 1. With a combined uncertainty of 14C /12C = 130 fmol/mol (F14C = 0.11), initial performance of the calibration-free instrument is sufficient to investigate a variety of applications in radiocarbon measurement science including the study of biofuels and bioplastics, illicitly traded specimens, bomb dating, and atmospheric transport.
“…1,2 High-precision measurements also have applications in forensic science and illicit trade. 3 These applications in quantitative 14 C science require world-wide intercomparisons between measurement facilities, specifically for facilities performing liquid scintillation counting and accelerator mass spectrometer (AMS). 4 Recent AMS intercomparisons have focused on high-precision (≤1 %) applications in atmospheric 14 C science, where agreed-upon standards for gas handling, sample preparation, and calibration are needed to realize ultimate sensitivities.…”
High-precision measurements of radiocarbon (14C ) near or below a fraction modern 14C of one (F14C ≤ 1) are challenging and costly. An accurate, ultra-sensitive linear absorption approach to detecting 14C would provide a simple and robust bench-top alternative to off-site accelerator mass spectrometry facilities. Here we report the quantitative measurement of 14C in gas-phase samples of CO2 with F14C < 1 using cavity ring-down spectroscopy in the linear absorption regime. Repeated analysis of CO2 derived from the combustion of either biogenic or petrogenic sources revealed a robust ability to differentiate samples with F14C < 1. With a combined uncertainty of 14C /12C = 130 fmol/mol (F14C = 0.11), initial performance of the calibration-free instrument is sufficient to investigate a variety of applications in radiocarbon measurement science including the study of biofuels and bioplastics, illicitly traded specimens, bomb dating, and atmospheric transport.
“…Chemical bar‐coding already allows for the identification of origin and in due course could allow for unambiguous tracing, tracking and assignation‐of‐origin for all ivory handled (Cerling et al. ; Wasser et al. ).…”
Section: Discussionmentioning
confidence: 99%
“…It may be time to treat natural elephant ivory as a material and commodity of the past, at least for now while the authorities are battling to contain the illegal market. Chemical bar-coding already allows for the identification of origin and in due course could allow for unambiguous tracing, tracking and assignation-of-origin for all ivory handled (Cerling et al 2016;Wasser et al 2017). After all, some range states will continue to push the argument that natural deaths and other legally accepted reasons for the death of an elephant can lead to the accumulation of ivory that could, and in their views should, contribute via monetarization to elephant conservation.…”
Ivory carves well and lasts long even under heavy usage. Its use over millennia are testaments to its value for household items, high-value ornaments and weaponry as well as false teeth and early hipreplacements. Indeed, exceptional toughness is required of the elephant's ivory because its tusk is used by the animal to leverage trees to breaking point or act as weapon in fights between bulls the size and weight of trucks. A number of studies have shown elephant ivory to be a highly non-isotropic material with complex 3 dimensional structures and network of porosity. Combined, these properties give ivory its qualities so desirable by carvers, pianists, artists and pool players. In this brief overview we focus on the structures and material properties of elephant ivory, many of which are shared by other types of ivories.
“…Although classified as Vulnerable by IUCN, the Elephant was not considered in this group because we assumed the scientifically well-established division in two separate species, Forest and Savanna Elephants, which have hitherto not been evaluated by IUCN. Given the precipituous decline of Forest Elephant due to poaching and its very low intrinsic growth rate, the species may qualify to the Endangered or even Critically Endangered status (e.g., Cerling et al 2016;Poulsen et al 2017;Turkalo et al 2017). Black-faced Impala is a subspecies considered Vulnerable, though its parental species is classified as Not Threatened.…”
Section: Conservationmentioning
confidence: 99%
“…This interest has also been fuelled by appreciation that many mammalian species have critical influences on the structure and functioning of African natural ecosystems (Keesing and Young 2014;Malhi et al 2016), and that they may provide important services such as biological pest control in human-dominated landscapes (Kunz et al 2011;Sirami et al 2013;Taylor et al 2018a). At the same time, however, African mammals have become involved in some of the most challenging and controversial conservation problems in the world, due in particular to the rapid growth of human populations, agricultural and pastoralism expansion and the associated loss of natural habitats (Laurance et al 2014;Searchinger et al 2015), deforestation (Hansen et al 2013), conflicts due to crop raiding (Hoare 2015;Seiler and Robbins 2016) and predation on people and livestock (Loveridge et al 2017;McNutt et al 2017), and poaching for bushmeat (Wilkie et al 2016;van Velden et al 2018) and international trade (Biggs et al 2013;Wasser et al 2015;Cerling et al 2016). Conservation of African mammals is thus at a crossroads, with a combination of multiple threats and opportunities, demanding a good understanding of species diversity and ecological requirements, and how they interact with humans in the context of complex and ever changing social-ecological systems.…”
Scientific investigations on the mammals of Angola started over 150 years ago, but information remains scarce and scattered, with only one recent published account. Here we provide a synthesis of the mammals of Angola based on a thorough survey of primary and grey literature, as well as recent unpublished records. We present a short history of mammal research, and provide brief information on each species known to occur in the country. Particular attention is given to endemic and near endemic species. We also provide a zoogeographic outline and information on the conservation of Angolan mammals. We found confirmed records for 291 native species, most of which from the orders Rodentia (85), Chiroptera (73), Carnivora (39), and Cetartiodactyla (33). There is a large number of endemic and near endemic species, most of which are rodents or bats. The large diversity of species is favoured by the wide
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