The Duke of Cambridge has hailed progress in combating the illegal wildlife trade as an "all-too-rare example" of the world uniting behind a cause.
William was speaking at a gala dinner in central London hosted by the charity Tusk, which works to protect wildlife across Africa.
He has been a royal patron of Tusk since December 2005 and praised its conservation efforts, pointing to recent commitments from the UK and China to curb the ivory trade.
But he warned against complacency, saying species including lions and tigers are facing an existential threat.
He told the Roundhouse in Camden on Thursday night: "You will have heard me talk about the illegal trade before.
"It is barbaric, it destroys livelihoods and communities, and it supports organised crime.
"The world is a worse place for it, and we must stamp it out. I have always argued that, while the problem is serious, it is beatable."
China's decision to close domestic ivory markets was described by William as an example of "great leadership", before adding: "I am pleased to say that the British Government recently announced its plans to restrict sales of ivory within the United Kingdom, as well."
Tougher action is also being taken against the illegal wildlife trade in Africa, wedded with increased investment in protecting animals, he said.
"Two years ago, much of this would have seemed unthinkable," William continued.
"It is an all-too-rare example of the world coming together to advance a cause for the sake of all humankind.
"We are going to have to work much harder, and think much deeper, if we are to ensure that human beings and the other species of animal with which we share this planet can continue to co-exist."
The Duke has for years rallied against the ivory trade, voicing concern last year the African elephant would have disappeared from the wild by the time Princess Charlotte turns 25.
He had earlier mingled with guests including Dragons' Den star Deborah Meaden, a Tusk trustee, and the charity's chief executive Charlie Mayhew.
Liz Bonnin, the broadcaster famed for her wildlife documentaries, praised the Duke for highlighting the importance of conservation.
Speaking after she met William, she told the Press Association: "It's never been more important, not least because his royal highness has come to offer support - there has never been a more important time to work in conservation."
She added: "Wouldn't it be amazing if we could get him to come on one of our documentaries? He is eloquent, he is so charismatic."
Chairman of Tusk, Stephen Watson, also paid tribute to the evening's royal guest.
He said: "The Duke has been an incredible supporter of Tusk.
"He is passionate about what we can and need to achieve in conservation and we have worked very effectively with him to try and change attitudes."
Tusk has invested more than £35 million for projects in Africa since it was established 27 years ago.