By Kevin Heath
If you’ve every wondered how TRAFFIC estimates the annual global trade in ivory you can now see the maths behind it. The mathematical model used to estimate the trade based on seizures has been published on Plos One. The paper details the mathematical model used by the Elephant Trade Information System (ETIS).
ETIS tries to track the amounts of ivory being traded for the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and is managed by TRAFFIC. Its database now has over 20,000 records built up since 1989.
The paper has been published by University of Reading, UK’s statisticians Fiona Underwood and Robert Burn and TRAFFIC’s Ivory Trade expert, Tom Milliken.
Because international ivory trading is illegal it is hard to quantify and mathematical models need to be used to try and estimate the level of trade. Getting exact figures of seizures is also difficult as some countries and authorities are more open about seizures than others. The model used by ETIS tries to compensate for these inequalities.
The model also needs to take into account the route that a piece of tusk could take on it’s way to it’s final destination. The paper notes that seizures could happen, ‘For example, an anti-poaching patrol in a protected area may stop poachers carrying a couple of tusks from an elephant they have just killed, border controls may intercept a containerised shipment with a concealed compartment of several tonnes of raw ivory as it moves between two countries to a processing centre, local police may seize worked ivory in a raid on retail outlets illegally selling ivory products, or customs may intercept tourists returning home with pieces of worked ivory in their luggage.’ Each of these steps could involve a different country with differing reporting abilities or willingness. More....