Clarence House has published Prince William's speech appealing for action to stop the "enormous" problem of the illegal poaching trade.
Prince William has labelled the illegal poaching of wild animals "economic sabotage" and warned that elephants, rhinos and tigers could "end up like the dodo" unless it is stopped.
He joined his father in co-hosting the wildlife conference with Environment Secretary Owen Paterson at St James's Palace.
Prince Charles earlier issued an impassioned plea, saying the fight against poaching was a "terrible race against time".
Mr Paterson warned that poaching was funding terrorism and other criminal activities and said "failure would be a shame on us all".
Prince Charles has said "we face one of the most serious threats to wildlife ever and we must treat it as a battle" at an international poaching conference.
Appearing at the conference alongside his son Prince William, he said: "As a father and soon to be grandfather I find it inconceivable that our children should live in a world bereft of these animals."
The Prince of Wales said poachers are using "weapons of war - assault rifles, silencers, night vision equipment and helicopters" in their pursuit of illegal animal gains.
He added that a growing global middle class are seeking exotic products from poaching to reflect their prosperity.
More than $8 billion a year is traded from the illegal poaching of wild animals, the World Wildlife Foundation warned.
Glyn Davies, director of programmes, told ITV's Daybreak: "It's one of the big illegal trades alongside arms, drugs. It's over $8 billion a year traded in wildlife alone and we of course very much appreciate the princes support convening this meeting today."
African elephant populations face possible extinction within a decade because of ivory poaching, campaigners have warned.
The WWF said that both black and white rhino are under unprecedented attack for their horn, which is being traded as a lifestyle drug, while wild tiger numbers across Asia have dropped by more than 90% in the last 100 years.
At an event today the Prince of Wales and the Duke of Cambridge will speak alongside Environment Secretary Owen Paterson to guests from countries affected by the illegal wildlife trade.
They will urge for stricter laws against the criminals involved and help for rural communities to find viable alternatives to illegal wildlife trade.
The Prince of Wales and Prince William will address guests from 26 countries on the 'serious crime' that is the illegal wildlife trade.
Speaking with Environment Secretary Owen Paterson they will call for a global partnership and urgent action to end wildlife crime. They will call for:
- A reduction in demand for endangered wildlife products in markets around the world
- A step up in law enforcement against the criminals involved
- Help for local/rural communities to find viable alternatives to illegal wildlife trade
The Prince of Wales and Prince William are to host a conference later today which will call for a global partnership to stop the illegal trade in wildlife.
Wildlife losses have reached unsustainable levels, with tens of thousands in some places, the World Wide Fund for Nature said.
It added that the world is currently faced with an "epidemic" of poaching and trafficking of illegal wildlife products, caused by an increase in demand, particularly from south-east Asia.
The conference, in conjunction with Defra will be the first stage in a process which will result in key countries signing a declaration at a meeting this Autumn, to end the illegal trade in wildlife.