Determination of Age and Geographical Origin of

African Elephant Ivory

Research project supported by the German Federal Agency for Nature Conservation and funded by the Federal Ministry for the Environment,

Nature Conservation and Nuclear Safety

First progress report for the project part ‘Geograp hical Origin’ 01.07. – 31.12.2010

Author:

Stefan Ziegler, WWF Germany

Translated from the original German version by Claudia Denkl, German Federal Agency for Nature Conservation

1. Project description In the 1980s the international trade in ivory led to a dramatic decrease of the population in many African countries. In 1989 the international community listed the African Elephant on Appendix I of CITES, and thus prohibited any commercial ivory trade. The strict trade prohibi-tion and effective protective measures allowed the elephant populations in some African countries to recover, above all in Eastern and Southern Africa. While maintaining strict pro-tection these countries were given the opportunity to deal with elephant products. Neverthe-less, so far CITES has only allowed one-off sales and does not allow free trade of products made of elephant ivory. One of the main arguments for the quasi trade prohibition is the fact that it is very difficult to distinguish legal ivory from illegal ivory in the markets, so that the legal ivory trade would provide a perfect cover for smuggling. The isotope enrichment of cer-tain chemical elements in the tusks of elephants is a good method to reliably identify the ori-gin of elephant ivory.

The geographical origin of ivory is determined by a combination of various geochemical rou-tine analyses. Most common and most successful is the determination of the isotopic com-position of the element strontium (Sr). But the composition of the stable isotopes carbon (C), nitrogen (N), oxygen (O), hydrogen (H) and sulphur (S) also allows a reliable assessment of the provenance, as elephants ingest these isotopes with the food they consume. For exam-ple, the isotopic composition of the element strontium in the food consists of the isotopes 87Sr and 86Sr that are combined in a distinct ratio that is related to the chemical composition of the geological sub-stratum: young volcanic regions such as the East African Rift are character-ized by a low 87Sr/ 86Sr ratio, whereas older parts of the earth's crust have a high 87Sr/ 86Sr ratio. Carbon and nitrogen isotopes can serve as indicator for the climate zone the elephant lived in. A very low δ13C ratio indicates densely forested habitats, a high ratio is indicative of savannah landscapes. In a similar way, a low δ15N ratio suggests humid conditions, whereas in drier elephant habitats a rather high ratio can be expected. Hence a relatively correct de-termination of origin is possible by defining the chemical composition of the tusks. The results of the analysis of about 500 geo-referenced ivory samples from museums, col-lections and big game hunters will allow the setup of a reference database. Isotope distribu-tion maps of elephant ivory can be generated by using geo-statistic procedures. This data-base can be consulted for the determination of the geographical origin of illegal ivory and bring about a better coordination of protection measurements on international level. 2. Goals of the research project Until the end of the year 2012 the following goals shall be reached: Development of a reference database for ivory: A method will be established that can be applied for the determination of the geographical origin and the validity of the geographical indication of ivory. Application of the reference database for the enforcement: The reference database for elephant ivory will be suggested to national authorities and the international community of states as a support to enforcement.

2.1 Operating schedule

Activities (quarter of the year)

III

2010

IV

2010

I

2011

II

2011

III

2011

IV

2011

I

2012

II

2012

III

2012

IV

2012

Literature review

X

Collection of samples

X X X X X X

Measurement of isotopes

X X X X X X X X

Setup of the database

X X

Evaluation and analysis

X X X X X X

Press relations and awareness raising

X X X X X X X X

Publication and presenta-tion of results

X X X

Preparation of a side-event for CITES CoP 16

X

Creation of a manual for the database (structure, application spectrum)

X X

3. Activities during the report period The description of activities is based on the list of the planned activities as shown in para-graph 2.1 (above). Because of the high public interest in the topic ‘ivory’ the implementation of tasks planned for the year 2011 has already been started.

3.1 Planned activities Literature review: The literature research showed that first studies on the isotopic composi-tion and geographical origin of elephant ivory were already conducted in the 1990s by South African scientists (Vogel et al., 1990; van der Merwe et al., 1990). These early studies indi-cated that forest elephants could be distinguished from savannah populations by the 13C/ 12C-composition of the ivory. But doubts arose concerning the sufficiency of these differences with regard to the requirements of CITES. For this reason Van der Merwe et al (1990) tried to achieve firm results by additionally applying the strontium isotopes 87Sr and 86Sr. They tested more than 100 ivory samples from 10 African countries and were able to distinguish most elephant populations by combining the 13C/ 12C-, the 15N/ 14N- and the 87Sr/ 86Sr-isotopes. Studies made by Koch et al. (1995) indicated that anthropogenic changes in the land use could chance the 15N/ 14N-values significantly. However, Koch et al (1995) and Culotta (1995) raised concern that results based on the stable isotopic composition would be court-proof. In the course of technical progress regarding the methodologies further studies with ele-phant ivory were conducted by Ishibashi et al. (1999) and Cerling et al. (1999, 2003, 2004,

2007). These authors indicated clearly that the measurement of stable isotopes contained in the ivory is a reliable method for the determination of the geographical origin of ivory. But until now no scientific studies were made concerning the relation of hydrogen-isotopes (D/H) or sulphur in African elephant ivory. This research project is a pioneering study in this field. Only since a few years the model of isotopic maps has been established in the applied bio-sciences (Sellick et al., 2009; Ehleringer et al., 2010). These applications connect the attrib-utes of process based models with spatial information, and therefore allow the prediction of expected events or test results in areas from which no data are available yet. An isotopic map for elephant ivory is currently not known and the research project enters uncharted terri-tories with that. Acquisition of samples: prior to the official start of the project, georeferenced samples were collected from the following museums: Senckenberg Museum (Frankfurt), State Museum for Natural History (Stuttgart), Zoological Museum of Hamburg University, Museum of Natural History (Berlin), Zoological State Collection (Munich), Museum of Natural History (Stock-holm), Natural History Museum (London), Finnish Museum of Natural History (Helsinki). Some additional large European museums of natural history in Paris, Brussels and Leiden as well as some smaller museums of natural history in Germany will be addressed in the course of the next weeks. From above mentioned museums 89 samples, from 18 African and 6 Asian elephant range states could be acquired, composed of 16 samples from Asian ele-phants and 73 samples from African elephants. The quantity of samples accounts from one to 13 samples per country with Cameroon, Tanzania and Mozambique being supplied quite well. But there are many countries from which there are presently only one or two samples available. The oldest sample is from Nigeria and dated back to 1854, the latest sample comes from a juvenile female elephant from South Africa that died in 1988 on the flight to Italy and whose tusks are owned by the Natural History Museum in London. The exact local-ity within a country where the ivory was found is not always known, which makes it difficult to use these samples for the reference database. For these samples, special calibration meth-ods have to be developed and applied to make it possible to locate the ivory. Besides, not all the samples are dated. This fact has to be taken into consideration as the 13C / 12C-ratio is changing due to the enrichment of the atmosphere with CO2 from the incineration of fossil fuel deposits. The project participants tried to integrate the African elephant range states concerning the provision of georeferenced ivory samples. Unfortunately this process proved to be very diffi-cult. The project was presented at the third Elephant Meeting in Nairobi in November 2010 (see presentation in attachment 1) and several states were interested in an active coopera-tion: Kenya, Zambia, Tanzania, Burkina Faso, Cameroon, Benin, Botswana, Namibia, South Africa, Swaziland. But the follow-up process concerning the sampling in the range states was slow. Especially in the states of Southern Africa the permission for the provision of genetic material seems to be more intricate since the last two conferences of the parties of the CBD. Even personal contacts to the relevant CITES authorities were not successful yet. Although the project partners, German Federal Agency for Nature Conservation and WWF, aim to draw attention to the project by writing official letters and e-mails, it became clear that an active cooperation with the elephant range states is complex and time-consuming. But there are good chances for sampling in two game reserves in Burkina Faso next spring. The cooperation with the International Council for Game and Wildlife Conservation (CIC) turned out to be very promising. In the circle of acquaintances of the president of the CIC’s Tropical Game Commission, 12 German big game hunters could be mobilized to make their trophies available for sampling. Although the German big game hunters are traditionally hunt-ing in Southern Africa, there are also tusk from Cameroon among these trophies. Through private contacts of the WWF to Portugal, six Portuguese big game hunters could be ad-dressed who hunted elephants in lusophonic Africa. The CIC will start an international appeal to hunters which will hopefully result in the provision of samples from western- and central

African elephant ranges. Furthermore, the main office of the German Hunting Associating (DJV) will sent a letter to the 1,200 district chairmen, introducing the research project. Addi-tionally, a press release will be distributed which will be printed by several regional associa-tions of the German Hunting Council in February. Measurement of the isotopes: The activity ratio of hydrogen, carbon, nitrogen, oxygen and sulfur in the 89 samples provided by museums was determined in November 2010. At first problems arose with the preparation of the samples because the ivory needs to be pulverized for a good homogeneity and combustion of the material. The laboratory solved this by shock-freezing the samples in liquid nitrogen and then crushing them. By adding dichlormethane, non-polar components (especially lipids) were separated and extracted. The powder gener-ated in this way can be burned in an elementary analyser. By this, the relevant isotopes can be brought into gas form, lead into a mass spectrometer and the relative relations can be measured. Setup of the database: The basic structure (see figure 1) was developed according to the concept of Ehleringer et al. (2010). Several datasets are already included. Besides the measured values of the stable isotope relations there are datasets for geology, climate, alti-tude, vegetation represented by the relation of plants with C3– and C4– photosynthesis path-ways, distribution of hydrogen isotopes in the precipitation and distribution of the elephant habitats.

Figure 1: Conceptual basis of the reference database for ivory The values are integrated into a GIS-model as point data, vector data and raster data and therefore different parameters can be combined. For example, it is possible to visualise the percentage of potential C4-vegetation in the African elephant habitats (see figure 2) or do statistic analysis. The site-related allocation of the datasets also makes it possible to extrapo-late the values. This is important as it will hardly be possible to acquire ivory from all African

elephant ranges. A geostatistical method, the so-called Kringing, allows to extrapolate the values for regions that are situated between two georeferenced find spots. The reasonability and accuracy of the extrapolation can be verified by the other geodata included in the data-base (e. g. climate, vegetation).

Figure 2: Distribution of potential C4-vegetation in the known and suspected African elephant habitats 3.3 Unplanned activities Press relations and awareness raising: A joint press release of the University of Mainz, WWF and the German Federal Agency for Nature Conservation in November 2010 attracted much attention, not only in Germany but also internationally. It was printed in the German news-paper ‘taz’ (http://www.taz.de/1/zukunft/umwelt/artikel/1/elefantenjagd-mit-kohlenstoff-isotopen/) and the ‘Science Daily’ (http://www.sciencedaily.com/releases/2010/11/ 101126094538.htm). It was even possible to conduct an interview with the Swedish radio. Publication and presentation of the results: A peer-reviewed one-page report was printed in the TRAFFIC Bulletin in December 2010: Ziegler, S. & Jacob, D., 2010. Development of a spatial reference database for ivory. TRAFFIC Bulletin 23(1): 4. Within the framework of the colloquium ‘Isoscapes: A panacea to determine the provenance of illegally traded ivory?’, held by the Institute for Ecology, Evolution & Diversity of the Goethe-University Frankfurt, the research project was presented to interested students and scientists.

4. List of literature Cerling, T.E., Harris, J.M. & Leakey, M.G., 1999. Browsing and grazing in elephants: the iso-tope record of modern and fossil probiscideans. Oecologia 120: 364-374.

Cerling, T.E., Harris, J.M. & Passey, B.H., 2003. Diets of East African bovidae based on sta-ble isotope analysis. Journal of Mammalogy 84: 456-470.

Cerling, T.E., Hart, J.H. & Hart, T.B., 2004. Stable isotope ecology in the Ituri Forest. Oecologia 138: 5-12.

Cerling, T.E., Omondi, P. & Macharia, A.N., 2007. Diets of Kenyan elephants from stable isotopes and the origin of confiscated ivory in Kenya. African Journal of Ecology 45: 614-623.

Culotta, E., 1995. Ivory identity crisis still unsolved. Science 267: 1264.

Ehleringer, J.R., Thompson, A.H., Podlesak, D., Bowen, G.J., Chessonleslay, L.A., Cerling, T.E., Park, T., Dostie, P. & Schwarcz, H., 2010. A framework for the incorporation of isotopes and isoscapes in geospatial forensic investigations. In: West, J.B., Bowen, G.J., Dawson, T.E. und Tu, K.P. (Eds.) Isoscapes – Understanding movement, pattern, and process on Earth through isotope mapping. Springer. Pp.357-387.

Ishibashi, H., Takeuchi, T., Whyte, I. & Koike, H., 1999. Delta 15N and delta 13C measure-ments from the African elephant, Loxodonta Africana, used for ivory sourcing. Bulletin of the Graduate School of Scocial and Cultural Studies, Kyushu University 5: 1-8.

Koch, P.L., Heisinger, J., Moss, C., Carlson, R.W., Fogel, M.L. & Behrensmeyer, A.K., 1995. Science 267. 1340-1343.

Sellick, M.J., Kyser, T.K., Wunder, M.B., Chipley, D. & Norris, D.R., 2009. Geographic varia-tion of strontium and hydrogen isotopes in avian tissue: implications for tracking migration and dispersal. PLoS ONE 4(3): e4735.

Van der Merwe, N.J., Lee-Thorp, J.A., Thackeray, J.F., Hall-Martin, A., Kruger, F.J., Coet-zee, H., Bell, R.H.V. & Lindeque, M., 1990. Source-area determination of elephant ivory by isotopic analysis. Nature 346: 744-746.

Vogel, J.C, Eglington, B. & Auret, J.N., 1990. Isotope fingerprints in elephant bone and ivory. Nature 346: 747-749.

Annex 1: Presentation of the project at the 3rd Elephant Meeting in Nairobi in November 2010

Age determination and development of a spatial reference database for elephant ivory

K. Hornig 1) & S. Ziegler 2)

1)Federal Agency for Nature Conservation; Bonn, Germany2)International Center for Ivory Studies, Johannes Gutenberg

University; Mainz, Germany

Scheme to identify the provenance of ivory- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

-Need for Support

Isotopy (H,O,Sr,C,N,S)

Schreger lines

Visual inspection and optical microscopy

no Schreger lines

Exemption of ivory(bone, vegetable ivory, synthetics, etc.)

Cases of doubt(burnish, sections, etc.)

<90°: mammoth >90°: elephant (Asian, African)

SpectroscopyRaman, FT-IR, UV-fluorescence

mammoth ivory elephant ivory non-destructive

destructive

International Center for Ivory Studies at the University of Mainz, Germany

Isotopy

Isotopes are different types of atoms of the same chemical element, each having a different number of neutrons (N). In a corresponding manner, isotopes differ in mass number but never in atomic number (Z).

Average abundance: 98.9% 1.1%

Isotope analysis is the identification of isotopic signature, the distribution of certain stable isotopes and chemical elements within chemical compounds.

N

Z

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

-Need for Support

Elephants and their isotopic environment

Local climate, altitude, geological conditions and food influence the isotopic composition of ivory.

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

-Need for Support

Elephants and their isotopic environment

Hydrogen (2H/1H), Oxygen (18O/16O):climate, altitude, distance to the sea.

Strontium (87Sr/86Sr; 90Sr):geology (age und composition), nutrition.

Carbon (13C/12C/14C):food composition (C3 / C4 plants).

Nitrogen (15N/14N):evaporation, not well understood.

Sulphur (34S/32S); Thorium 228Th/232Th: not well understood.

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

-Need for Support

First isotopic fingerprints

By overlaying isotope ratios of C, N and Sr several researchers were able to distinguish ivory from different regions and countries.

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

-Need for Support

Project Goal

Creation of the ivory reference database: Establishing methods that can be used to determine the age and the origin of ivory and to check the accuracy of the designationof origin.

Implementation of the reference database for the pr otection of species:The elephant ivory reference database will be suggested to national authorities and the international community of states as a support to enforcement.

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

-Need for Support

CITES Context

• Framework: CITES CoP14, Decisions 14.75 to 14.79.CITES CoP15, Document 44.1, Paragraph 26.

• African Elephant Action Plan: Strategy 1.4 - Strengthen the enforcement of laws relevant to conservation and management of African elephants.

Activity 1.4.3 - Identify origin of seized ivory and determine the pattern of illegal trade routes and networks for ivory smuggling using available DNA analysis and other forensictechniques .

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Conceptual Framework

modified from: Ehleringer et al. (2010)

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Age determination

By combining the analyses of radio nucleotides the time of death of an elephant can be determined with a high degree of certainty.

0,20

0,25

0,30

0,35

0,40

0,45

0,50

1940 1950 1960 1970 1980 1990 2000 2010

Year

Act

ivity

of R

adio

acar

bon

per g

ram

m C

arbo

n

Radiocarbon dating ambigous

Determination of Strontium-90 Determination of

Thorium-Isotopes

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Spatial modelling

modified from: van der Veer & Höskuldsson (2009)

Modelling approach

Sampling georeferenced ivory

Signals from stable isotopes

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

δ13C Isoscape for ivory

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Based on 50 ivory samples from European museums

Spatial modelling

modified from: van der Veer & Höskuldsson (2009)

Strength of the isotopic map approach is based on using of a combination of maps that each provide additional detail.

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

δ13C, δ15N and δ2H

δ15N

δ2H

δ13C

Mapping example (given range for δ13C)

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Based on 50 ivory samples from European museums

Mapping example (combined ranges for δ13C + δ15N)

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Based on 50 ivory samples from European museums

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Based on 50 ivory samples from European museums

Mapping example (combined ranges for δ13C+δ15N+δ2H)

Challenge

1. Probable source location by comparison with stable isotope database.

2. Prove that samples do not derive from any other geographic region.

3. Supplementary information from the field.

Elephant migrate across country boundaries! - Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Outline

Short term • Collecting samples (in situ, stockpiles, museums, hunting

trophies).• Analysis of stable and radioactive isotopes.Medium term• Evaluation of results (discriminant analysis and other

advanced statistics).• Computing isoscapes for ivory. • Strengthen international scientific cooperation.Long term• Development of an open access webapplication to facilitate

cooperation and disseminate information to target audience. • Development and distribution of a standard method for the

quantitative analysis of elephant ivory.

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support

Need for support

In order to make this project a success, we require:

•500 georeferenced ivory samples from proximal end o f the tusk with a weight of approx. 0.25g for spatial database.•20 ivory samples of known age from proximal end of the tusk with a weight of 10g each for age determinatio n.

Your kind support is highly appreciated! Please contact:

Stefan Ziegler at zieglst@uni-mainz.deor

Karin Hornig at karin.hornig@bfn.de

Thank you for your attention!

- Introduction

- Starting Point

-The Project- Framework- Modeling-Challenges- Program

- Need for Support