期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2016
卷号：113
期号：47
页码：13330-13335
DOI：10.1073/pnas.1614938113
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceC-14 dating methods can be used to determine the time of death of wildlife products. We evaluate poaching patterns of elephants in Africa by using 14C to determine lag time between elephant death and recovery of ivory by law enforcement officials. Most ivory in recent seizures has lag times of less than 3 y. Lag times for ivory originating in East Africa are shorter, on average, than the lag times for ivory originating in the Tridom region (Cameroon-Gabon-Congo). The 14C data show little or no evidence that large-scale ivory shipments contained ivory stockpiled over long time periods. Little, if any, "old" ivory (i.e., >10 y) seems to contribute to large ivory shipments. 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.
关键词：wildlife ; forensics ; isotopes ; Africa ; genetics
