Elephant range and population, strontium isotopes, and genetics combine to give local-scale specificity to ivory hotspot tracking
We use Sr isotopes to increase the precision of DNA-based origin estimates of wildlife products. Population information is used to develop Sr isotope Elephant Polygons that are overlaid onto the region of origin identified by DNA assignment to determine the sources of seized ivory samples. Our approach is cognizant of isotope mixing due to isotope turnover within animals and also of the large home range of elephants or other mobile species. Genetic information from 3 different law enforcement ivory seizures suggests a region of origin confined to Kenya and Tanzania in eastern Africa. We determine characteristic <sup>87</sup>Sr/<sup>86</sup>Sr ratios for each of 25 different Elephant Polygons within this region using analyses of more the 600 known-origin reference samples. Using both the <sup>87</sup>Sr/<sup>86</sup>Sr ratios of the seized ivory samples and elephant population estimates from individual Elephant Polygons we find that at least 75 % of the samples likely came from a single Elephant Polygon which includes the Tsavo National Parks in Kenya and the Mkomazi National Park in Tanzania. A few samples may have come from other regions, most likely from Tanzania. This study illustrates the value of combining genetics, isotope geochemistry, and population surveys in wildlife forensics studies.
Authors
- Zofia A. Kaliszewska (ORCID: https://orcid.org/0000-0001-6917-8665)
- Francis Kirera (ORCID: https://orcid.org/0000-0001-5599-9163)
- Tobias Odhacha (ORCID: https://orcid.org/0000-0003-1507-1111)
- Thuan Chau (ORCID: https://orcid.org/0000-0003-0390-4921)
- Thure E. Cerling (ORCID: https://orcid.org/0000-0002-3590-294X)
- Kendra L. Chritz (ORCID: https://orcid.org/0000-0002-8026-6428)
- Diego P. Fernández (ORCID: https://orcid.org/0000-0002-4727-5031)
- Samuel K. Wasser (ORCID: https://orcid.org/0000-0002-2678-1904)
- Julia V. Tejada‐Lara (ORCID: https://orcid.org/0000-0003-2307-6764)
- Yves Hoareau (ORCID: https://orcid.org/0000-0002-2807-2247)
- Jory Lerback (ORCID: https://orcid.org/0000-0003-1615-3530)
- Kevin T. Uno (ORCID: https://orcid.org/0000-0001-6882-0900)
- Mary K. Kuhner (ORCID: https://orcid.org/0000-0002-6986-3870)
- George Wittemyer (ORCID: https://orcid.org/0000-0003-1640-5355)
- Paula Kahumbu
- Scott A. Blumenthal (ORCID: https://orcid.org/0000-0002-1173-0151)
- Evan L. Kipnis (ORCID: https://orcid.org/0000-0001-8544-760X)
- Lesley A. Chesson (ORCID: https://orcid.org/0000-0002-8457-9341)
- David K. Korir
- Cecelia Chisdock
Institutions
- California Institute of Technology (US)
- Defense Information Systems Agency (US)
- Lawrence Livermore National Laboratory (US)
- Missile Defense Agency (US)
- Harvard University (US)
- Tanzania Wildlife Research Institute (TZ)
- University of British Columbia (CA)
- Kenya Wildlife Service (KE)
- Mercer University (US)
- University of Oregon (US)
- University of Washington (US)
- University of Utah (US)
- UCLA Health (US)
- Harvard University Press (US)
- Picarro (United States) (US)
- IsoForensics (US)
- Notre Dame University (PH)
- Laboratory for Research on Enterprise and Decisions
- City & Guilds Group (GB)
- Colorado State University (US)
Publication Details
- Journal
- Isotopes in Environmental and Health Studies
- Published
- 2025-12-08
- DOI
- https://doi.org/10.1080/10256016.2025.2596896
- Primary Topic
- Identification and Quantification in Food
- Type
- article
- Field-Weighted Citation Impact
- 0.00