These trade ties have made illegal ivory shipments much easier to set up, Thomas said.
"The fact that they are shifting such large quantities of ivory suggests a move towards more organized crime," he added.
"It takes a well-organized operation to shift as much as a ton, which is about half a shipping crate. It's not like smuggling a piece of ivory in your hand luggage."
The trafficking is oiled by open-air markets in countries such as Angola, where illegal ivory is freely sold, the TRAFFIC team said.
(Read related story: "Illegal Ivory Trade Boosted by Angola Craft Markets, Conservationists Say" [October 27, 2006].)
Many ivory items offered at Angolan markets originated in neighboring countries such as the DRC, researchers discovered.
"For example, some of the animals that the ivory has been carved into [it] are Central African species," Thomas said. "They aren't animals that occur in Angola."
Susan Lieberman, director of WWF's Global Species Program, speaking from Rome, Italy, said increased seizures of such ivory surely means a surge in elephant killings by poachers.
Since there's no evidence the seized ivory had been stored, the implication is that it's fresh, she said.
The slaughter includes that of threatened populations of forest elephants in the Congo Basin, Lieberman added.
The research team is calling for a crackdown on poorly regulated African ivory markets that contravene CITES, an international treaty that monitors illegal trade in endangered wildlife.
"There is a CITES action plan to clamp down on illegal domestic ivory markets," Thomas, of TRAFFIC, said.
"Ethiopia has acted on it, and it's had an immediate effect. We'd like to see other countries follow suit."
In China, the team noted, there has been a significant improvement in law enforcement and policing of local markets, yet Chinese ivory traffickers in Africa are operating largely unchecked.
The report says that Chinese citizens have been arrested or detained or have fled in at least 126 major ivory seizures in African countries.
"It is imperative that China reaches out to the growing Chinese communities in Africa with a clear message that involvement in illegal ivory trade will not be tolerated," Milliken, the study's lead author, said.
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