Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade

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. Patterns of trade differ by regions: East African ivory, based on genetic assignments of geographic origin, has a much higher fraction of “rapid” transit than ivory originating in the Tridom region of Cameroon–Gabon–Congo. Carbon-14 is an important tool in understanding patterns of movement of illegal wildlife products.

Optical Measurement of Radiocarbon below Unity Fraction Modern by Linear Absorption Spectroscopy

“…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.…”

Ivory as an Important Model Bio‐composite

“…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. ).…”

“…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.…”

The Mammals of Angola

“…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.…”

“…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.…”