By environment correspondent Alex Kirby

The future of the world's elephants is once more up for debate, with several countries arguing that they should be allowed to make regular sales of ivory.

Their proposals will be discussed in April at the meeting in Nairobi of the 148 signatories to the UN Convention on International Trade in Endangered Species (Cites).

A key pointer to the outcome of the debate is expected later this month, when independent experts report on their assessment of the proposals which are being tabled by Botswana, Namibia, Zimbabwe and South Africa.

Hard to refuse

The experts have been asked to report by Traffic International, set up by the World Conservation Union and the World Wide Fund for Nature to ensure that trade in wild plants and animals does not threaten nature conservation.

Sabri Zain of Traffic told BBC News Online: "The April meeting is going to be very interesting."

"It is very difficult to say to the southern African states 'No, you cannot sell your ivory', because we have to look at other factors as well.

"There have been reports of an increase in poaching from Kenya, and from Zimbabwe. But that's not to say that there is a global increase, or that any increase has been prompted by the limited sales of stockpiled ivory the southern Africans were able to make last year.

"And a reported increase in poaching may mean more enforcement, not more actual poaching."

The countries which sold the ivory last year, the ones which are tabling this year's proposals, earned about US $5 million for 49,574 kilograms - representing 5,446 tusks.

Opposing needs

They said they needed the money to fund wildlife conservation. Traffic says Zimbabwe has already channelled US $575,000 into the local communities where the ivory came from - about 40% of all it earned from the sale.

The southern African states also say they have more elephants than they have room for. They want to be able to sell the ivory from culled animals.

But other countries say that allowing the ivory to be sold last year encouraged poachers to take up their guns again, in the hope that Cites would soon lift its ban on the international trade.

Countries like Kenya, which relies for much of its foreign earnings on wildlife tourism, say allowing any resumption in the trade after last year's exceptional sale would encourage the return of the mass slaughter which saw Africa's elephant herds more than halved in the 1980s.

What is crucial to knowing whether elephants are succumbing to the poachers in large numbers once again is an effective way of monitoring what is happening, and two systems are in their early days.

Not ready

Cites is working on Monitoring Illegal Killing of Elephants (Mike), which reports on what is happening in the countries in Africa and Asia which have elephants.

Traffic, working with a team from the University of Reading in the United Kingdom, is developing Elephant Trade Information System (Etis), to monitor the trade in ivory.

Both Mike and Etis will report to future Cites meetings. But this will not happen by April.